The debate on the refurbishment or demolition of old buildings with the underlying need to boost environmental, social, and economic viabilities is a debate that has raged on in many countries over the centuries. According to ODPM (2003) report, UK policies have been reflected in the demolitions of insanitary slums constitutionally certified in 1880s (Power 1993). In the context of economic, environmental, and social viabilities, much debate on the best option to adopt, either to demolish or refurbish buildings, according to the 2003 proposed plan on Government’s sustainable communities with underlying debate on large scale demolitions of buildings has gained significant momentum (Commission on Environmental Pollution (RCEP) 2007). In the context of greenhouse gas emissions and thermal efficiency of the buildings with housing identified as one of the most single emitters of greenhouse gases, this study provides evidence of the need to refurbish old buildings as the most effective option to adopt. The basis for argument is a comparative study on the relative merits of demolitions and refurbishments on carbon greenhouse gas emissions from old buildings, new buildings, in relation to the stock that could achievably be demolished by 2050.
No empirical evidence has been adduced on the carbon reduction benefits that could be attained by demolishing old buildings with scantly evidence requiring complex modeling to support the little known facts. According to Boardman et al., (2005) the models little account for the carbon costs associated with the acquistion of new materials, energy consumption and associated greenhouse gas emissions in the concrete construction processes. That is in addition to processes on steel structures, new space requirements, environmental degradation because of land usage, and the movement of the materials as additional energy consumption processes when making new constructions (Barker 2006; Power 1993).
Studies conducted by SDC (2006) have projected that 70% of the current stock of buildings could be in existence by 2050 radically showing that only 10% of the current buildings could have been demolished. That is in addition to associated costs, adverse environmental implications, and the pace that can sustainably be attained in the demolishing processes (Power 1993). Demolitions have so far been embedded in social and political controversies, a fact that further reinforces the rationale for an environmentally and cost effective option of upgrading the old inefficient stock (Mumford & Power 2002).
In exploring a cost effective, sustainable, and environmentally effective option, further discussions on demolitions show strong social and political ramifications, with little adverse implications and oppositions on refurbishments (Rogers & Power 2000; Barker 2006). That is in addition to the high costs of acquiring new land, putting up new buildings, and associated energy inefficiencies in the construction process as additional factors that reinforce refurbishments of old buildings (Rogers & Power 2000).
Research by Shorrock and Utley (2003) and the UK Government Department for Communities and Local Government (DCLG) (2008) has shown that lack of political momentum and acumen in the direction of new constructions and effective usage of new structures in energy consumption, refurbishment makes a lead. In the context of refurbishments, the merits are evident in the perspectives of time, social and political implications, protection of current communities, and cost effective usage of existing buildings and other infrastructure (UK Government Department for Communities and Local Government (DCLG) 2006a). Projections on the relative merits of refurbishments include reduced aggregate carbon reductions because of lower energy consumptions, and accelerate the development of new technologies (Yates 2006).
Studies show that refurbishments lead to less than 50% carbon emissions that is being produced and added into the atmosphere with homes contributing significantly less 50% into the environment (Yates 2006). The answer is identifying the best methods of constructing and operating homes provides to optimize carbon reduction targets, which underlies responsibilities held over the future generations and the environment in general (Yates 2006).
This Dissertation explores in-depth on efficient and effective energy usage while optimally addressing social, economic, and environmental concerns associated with refurbishments. The study further provides potential knowledge effective use of properties to minimize energy usage while studying comparatively the options of demolitions with the ultimate goal of improving environmental impact because of the existing stock. In the context of the study, the aim and objectives are mentioned below.
The aim of the study is to explore refurbishment of old and inefficient buildings as the best options to adopt against demolitions for domestic buildings to boost the environmental, social and economic viabilities.
- To explore the effectiveness of the structured approach of demolitions on energy efficiencies of worst performing stocks on technical facts to inform a policy on refurbishments as the best option based on the viability of practical implications.
- To explore the impact of extensive demolitions, rebuilding, and refurbishment in relation to economic, environmental, and social issues with the underlying energy savings.
- To explore the appropriateness and level of demolitions and refurbishment required with an underlying need for improving the physical environment, sustainably retain the social structure of the affected communities, and optimize energy savings.
- To explore available options of energy efficient procedures that guarantee sustained supply of inexpensive housing with minimal land usage and environmental impact.
The study provides technical facts which support the most effective option to adopt with empirical evidence to support the rationale for refurbishment and renewal of old buildings. That is in contrast to the theoretical arguments on the need to demolish and embark on new constructions which have adverse implications on the political, social, economic, and environmental dimensions. Projections have shown that constructions, according to the stringent carbon emissions requirements could lead to a time lag and failure to meet and deliver on schedule new buildings on schedule.
Existing communities & Existing stock
Literature on existing stock shows a significant number of people in the UK live in urban areas accounting for 88%, occupying 99% of the homes that already had been built a year before (Yates 2006). Studies by Elevate East Lancashire (2004) and Power (2006b) argue that the need to renovate or to refurbish is entirely dependent on the approach the population uses to maintain a good level of sustainability of the existing environment in good shape, which informs the potential for renovation or refurbishment. That is reinforced by a technical feasibility report by Johnston, Lowe and Bell (2005) on the feasibility of refurbishments. Studies by Power and Houghton (2007) among other authors on the topic of refurbishments show that the level of existing neighborhoods, the level and concentration of housing, and the population that inhabits the buildings justifies the need for renovation instead of demolitions (UK Government Department for Communities and Local Government (DCLG) 2007). That is in addition to the challenges posed by existing social structure coupled with the income levels of the occupants. According to the current studies, the low income levels requiring large subsidies of the people who occupy the old houses require inexpensive supplies, and low priced housing, reinforcing the need for renovation instead of demolishing the old buildings (UK Government Department for Communities and Local Government (DCLG) 2007).
Studies contained in the Sustainability Development Commission report, SDC (2006) have shown that new buildings added into the existing stock only contribute 1% of the UK housing stock per annum. Results based on evidence show that a significant percentage of carbon emissions into the environment are generated from the 99% of the existing stock, which adds 27% of the carbon emission into the environment each year (Ireland 2005; SDC 2006; Boardman et al. 2005). The 27% carbon emissions come from 24 million homes in the UK, which are projected to be in existence by 2050, with only 13% of the 24 million homes having been removed, remaining with 22 million homes. The statistics indicate that 22 million homes could still be in existence by 2050 maintaining a near similar carbon emission trend. That is if the technical specifications of the homes could not have been altered in any way (Lararus 2002). The results indicate a sustained supply of carbon emissions without any significant deviations from the original calculations based on the construction momentum of 1% homes a year with 87% of the current homes still in existence. That is in addition to the statistical argument that even if 2 million homes are demolished per annum, an 87% of the current stock could still be in existence by the year 2050 (ODPM 2004).
When considered from the perspective of constructing 200, 000 homes per annum, the success rate could be nine million homes by 2050. Calculations show that at a rate of 200,000 homes a year, the current stock could constitute 70% of the entire homes by 2050 (PriceWaterhouseCoopers 2008). The feasibility of demolitions comes into dispute because of social, economic, time, environmental, and political factors. According to the SDC (2007) findings, the new stock of buildings are technically more energy efficient compared with the old stock. SDC (2007) further reinforces the argument that the performance of the old stock if improved could provide a significant improvement in energy efficiencies and reduce energy consumption by 60% upwards (Brook Lyndhurst 2008). That is in addition to the evidence which shows the current stock to be homogeneous requiring different refurbishment techniques and technical specifications. According to SDC (2007) report, the current stock is an aggregate of different occupancy levels, location, and construction type with different energy usage and greenhouse gas emissions contributions to the environment. With the reported differences in technical specifications of the homes, each building could require a specific retrofit for the purpose of improving the energy usage and greenhouse gas emissions (ODPM 2004).
Typical examples include timber frame houses and cavity wall built houses. A timber built frame could require radically different insulation approaches compared with a cavity built house measure (UK Office of Public Sector Information (OPSI) 2008). In cavity and timer frame constructions, energy usage levels and greenhouse gas emissions vary significantly, reinforcing the need for energy considerations when developing such a structure. Cavity wall constructions provide better energy usage and lower greenhouse gas emissions when enhanced with insulation linings, while a timber frame house could require additional linings to provide similar energy consumption and greenhouse gas emissions levels (Scottish Government 2007). A timber framed house suffers from dumpiness that requires an air gap to reduce and avert any possibility degradation (UK Government Department for Communities and Local Government (DCLG) 2007b). That is in addition to the extra insulation requirements that include external and internal insulation linings, which increase the costs of refurbishment compared with the costs incurred in refurbishing cavity wall building. Construction reports indicate the costs of refurbishing a timber frame house to the required energy consumption levels to be ten times the costs of refurbishing a cavity walled building (Mansfield & Pinder 2008). The findings show that walls with different insulations provide varying degrees of energy savings. According to available literature, best practice requirements indicate walls externally or internally insulated provide 0.35 W/m2K, while walls with cavity insulation provide 0.55 W/m2K (Shorrock & Utley 2003).
Considering a typical scenario, a cavity wall provides high insulation capabilities when used as a continuous overlying layer rigidly lined and fitted between the inner layer and the cavity of the wall (Everett 2007). The space in the cavities is filled with material such as glass fiber with variant materials having different thermal conductivities that vary with temperature as shown in figure 1 below. Figure 1 is a typical demonstration of the variations in thermal conductivities with changing temperatures of different types of glass that could be used in cavity linings. The glass fibers are into two categories, and little details could be divulged which bear relevance to the current study (Shorrock & Utley 2003).
Studies indicate that cavity wall constructions with a CERT subsidy require hundreds of pounds to complete for a resident. On the other hand, estimates show that a wall requiring only external and internal insulations could be significantly cheaper and a householder could only require installing the insulation (UK Office of Public Sector Information (OPSI) 2008). A cost benefit analysis shows that different types of cavity wall constructions made from different materials provide different energy and cost savings.
A detailed study indicates that the multidirectional composites provide coupling effects between the fiber layers (Everett, 2007). That is in addition to the fact that the cavity materials can be arranged in interleaving layers to provide similar thermal effects to achieve a parallel thermal heat transfer mode. CIBSE (2007) in the case for refurbishments argues that longitudinal, non-longitudinal, and unidirectional layers result into a parallel heat transfer constitutive mode in its principle frame leading to thermo-mechanical optimization of fiber optic insulation materials (BRE, 2003). A typical example of a cavity wall is illustrated in figure 2 below. The diagram illustrates the thermal conductivities of different materials used to provide thermal insulation of cavity wall, demonstrating some of the material requirements for the construction. Figure 2 is one of the variant structural approaches for the refurbishment of a wall, which can also be used in the construction of new buildings. On the other hand, figure 3 showing a typical example of water proof insulated roof. A completed part of a structure construction of a roof is indicated in the figure 4 partly, with the elements and part of the air flow shown.
A typical example of the best practice for a roof that has been refurbished is shown in figure 4 below.
Each of the elements used in the structure above can also be used in constructing the wall or in the refurbishment of the walls to attain high energy efficiency. The technical details demonstrate the requirements to be met which also have cost, time, and environmental, social, and political implications when considered on the refurbishment and demolition and construction options. Figure 3 above consists of details of a typically refurbished roof or previously constructed using similar materials that can be used for refurbishment to help in energy savings. In this case, the concept used is a building envelope in the design. That is in addition to making the underlying structure water proof reducing any chances of dampness in case a wooden frame structure is refurbished (BRE 2003).
The resulting structure provides insulation with the additional benefits of using a thermal break provided in the cavity wall. The underlying benefits include a reduction in heat losses because of low convectional currents, and low space heating costs.
In the context of the cost savings on energy realized from using an insulated house, and additional insulation requirements to attain high energy efficiencies, OPSI (2008) reports cost barriers associated with new constructions. That is in addition to the costs associated with demolition of old stocks, the time requirements for demolitions and construction of new houses, social and political implications and the effects on the social structures (BRE 2005a). In summary, not only cost barriers have implications on refurbishment or demolitions and construction of new stocks, but additional implications as mentioned above include time, effects on social structures, and environmental implications (EHCS 2004).
The construction of new stocks could require further considerations of the type of structures that define the old stock and additional implications on the society and the environment (Strathclyde University 2006). Investigations by Strathclyde University (2006) indicate that solid wall structures, timber framed structures, and structures with cavity walls which are appropriate for cavity wall insulations are difficulty to determine in other countries. According to a study by Strathclyde University (2006), statistical findings indicate that 70% of the old stocks in the UK have cavity walls that could allow for cavity wall insulations with Scotland having 74% of the buildings having cavity walls. According to the report by the Scottish Government (2007), the number of homes with cavity walls and timber framed are difficulty to determine, which a problem in Scotland is. The result is a radical departure from the housing units in the UK (WWF-UK 2008).
A cost effective analysis of the refurbishment against demolition and new developments, which are in favor of refurbishments show that refurbishments require less costly undertakings compared with demolitions and commencement of new constructions (UCL 2007). The rationale for refurbishments is reinforced by CERT UK which intends to reduce greenhouse gas emissions significantly. In that context, CERT UK has projected an annual CO2 savings equivalent to 4.2 Mt CO2, which accounts for only 2.7% of the total domestic emissions with the assumption that the total stock generates 152 Mt of CO2 annually (Shorrock & Utley 2003). Statistical figures provided by CERT UK show the 154 Mt CO2 target as the overall lifetime savings and not annual savings (Strathclyde University 2006).
Demolitions or Renovation
A study by Mumford and Power (2002) has shown that demolitions of the housing stock with high carbon emissions and low energy savings appear to provide a sustainable and most appropriate solution to the housing problem encumbered energy savings problems. In a study by Power (1993), demolitions and new constructions are processes identified as significant sources of energy consumptions and consequent release of greenhouse gases into the environment as modeled in figure 5 below. According to the study, demolitions consume time and energy with greenhouse gas emissions as by products.
In the above case, the demolition process requires a significant amount of energy in the destruction process as inputs, with the construction process requiring the production of construction materials to required specifications, fabrications, and specifications (Power 1993). The energy consumed in the process is released as by products as greenhouse gases into the environment contributing significantly to the greenhouse gas effects. In addition to the use of energy in various forms, additional use of water and other materials further pause health problems (Power & Mumford 2003).
As illustrated in diagram 1 above, the inputs also include energy in terms of soil movements and energy recycling and reuse and outputs in terms of greenhouse gases and other environmental degrading elements. The diagram provides the basis for analytically concluding in favor of refurbishments instead of demolitions and rebuilding new houses (Power & Mumford 2003).
The problem in this case is the fact that a significant number of the old stocks of houses were designed with energy inefficiencies and non-compliant to the policies on UK greenhouse gas emissions. In that context, there were no stringent requirements for energy compliance regulations which became effective from 1st October 2008. Demolitions could be a precursor to the construction of new homes which could comply with the energy efficiency regulations which could be best explained in the following statement which affirms that “we don’t just want to build more homes” (Mumford & Power 2002) and continues to affirm that “we want them to be better homes, built to high standards, both in terms of design and environmental impact and homes that are part of mixed communities with good local facilities” (Mumford & Power 2002) adding that “Our new homes need to be part of the solution to climate change; not part of the problem” (Mumford & Power 2002).
That is in addition to the poorly planned and organized urban dwellings with low income residents. In this case, the buildings do not comply with risks of condensability in the buildings, design flexibilities, and the usage of fabrics and other materials that satisfy the energy savings policies and building standards as shown in table 1 below. Here, the variants in the types of buildings and the standards outlined for each of the buildings in terms of energy consumptions such as in heating, and other necessities that lead to energy consumptions and greenhouse gas emissions (Ireland, 2005).
Studies indicate that renovations sometimes could be expensive if the goal to reduce fuel poverty and greenhouse gas emissions is to be attained. The cost ineffectiveness is determined by the suitability of the underlying structures, the impact of the inhabitability of the existing home, and the costs associated with the entire renovation process (Ireland 2005). That is in addition to the costs associated with the maintenance of the refurbished or renovated building as expressed in the statement “that current rates of VAT are heavily stacked in favor of demolition, as opposed to refurbishment” (Mumford & Power 2002).
Figure 6 above provide a summary of the profile of the results of demolition and consequent construction of new buildings against the refurbishment of old stock. The figure indicates the energy requirements with environmental implications and other factors associated with refurbishment and reconstruction of new buildings. To mentions, materials, and energy are required as additional inputs besides other local factors that include community structures. On the other hand, there is need for expending energy and other resources to construct the houses to the required legislation standards, and the adherence to the manual maintenance standards. In the other hand, it is clear from the diagram that refurbishments can be effected using recycled materials with the process having low noise, low energy consumptions, and other additional factors such as the maintenance of the social fabric and aesthetical preservation of the old houses and social structures.
Table 1 below is an illustration of the standard requirements to be met for a housing facility if the attainment of fuel and other energy efficiencies are to be attained. The table provides standards against which houses could be evaluated for renovation or refurbishment and demolitions for erecting new buildings. The table details average wall requirements, the specifications for ground walls, requirements for windows and wall, ventilation system requirements, thermal bridging allowance, among other requirements.
While the above table presents a strong case for demolitions to provide first hand solutions to environmental problems such as greenhouse gas emissions paused by the old non energy complaint stocks, demolitions have a downside worth exploring. Empirical evidence by Everett (2007) shows demolitions to be expensive in terms of financial investment and energy consumptions, goes against public support, and is painstakingly slow. That is in addition to the attitude developed by people who could even be beneficiaries of the demolition program and the reconstruction process for new structures (CIBSE 2007).
Estimates show that the number of demolitions achieved because of a government initiated program was 80,000 per annum in a mass clearance program in 1960s.The demolitions under government initiated program gained momentum reaching its peak in the 1980s. An estimated 2 million houses were cleared despite interruptions by the Second World War. It was one of the largest clearance programs initiated by the British Government (Power, 1993). The program was a success because of the subsidies provided by the Government propelled by the political will and other necessary force. The experience learnt from the demolitions was strong opposition to the demolitions coupled with demonstration leaving a disappointing experience not worth repeating. It could therefore impractical in the current era to carry out demolitions of the scale experienced in the latter century. During that period, demolitions were further opposed because of the old stock provided housing for low income earners providing latent value for the occupants.
Despite the opposition experienced during the demolitions era, some of the areas considered for demolitions included poorly maintained areas, the older inner city areas especially in the post war era of east London and the Midlands. With the considerations of the potential for providing shelter for the low income earners, the potential for renovation was further reinforced (Power & Mumford, 2003). A number of benefits associated with renovations contrary to demolitions could be realized and based on an economic, social, and environmental factors, could provide better stocks aligned to the standard requirements for energy consumption as detailed in table 1 above.
According to the foregoing considerations of demolishing buildings vs refurbishments, a number of strong cases have been presented which show refurbishments to provide superior solutions against demolitions and reconstruction of new stock (BRE 2003). According to the findings renovations makes the buildings more economically viable solutions to the environmental, social, and economic problems and provide solutions aligned to the income levels of the people living in the old buildings. In addition to that, the social structure of attractive houses remains with the aesthetical attractiveness the houses were built with. That is in addition to the learning experience from the Germany houses which have been refurbished to high energy usage standards, where the “The Empty Homes Agency (EHA) has demonstrated the feasibility, cost-effectiveness and energy gains of renovation” (Ireland 2005).
Energy reductions for domestic buildings in the UK
Of critical importance in the study are energy efficient and environmentally sound structures that that provide optimal use of energy with minimum and acceptable greenhouse gas emissions into the environment. No evidence has been presented on houses with zero greenhouse gas emissions and especially the old stock of buildings in the UK (BRE 2005a). Toward eliminating or minimizing to acceptable standards the greenhouse gas emissions into the environment, the UK government has designed policies that address energy reduction for use in domestic buildings. The policies could be aligned with the approach identified in the above study of renovations as the most appropriate approach for the old stock of buildings in the UK. In tandem with the policies on energy reductions, processes that could be factored into the renovation of energy inefficient buildings include introducing thermal envelopes and the use of simple sealing improvements (Harvey 2006).
As illustrated in the figure 4 above, the structure provides airtight ventilations to reduce energy losses into the environment (Everett 2007). Reducing ventilation is the current thinking with appropriate air flow to reduce air draughts that result into low temperatures with eventually cause energy consumptions because of heating. According to CIBSE (2007) draught proofing is one of the cost effective methods of reducing energy consumption and is possible by use of draught stripping, blocking chimneys that are not in use, and replacement of windows that leak. Draught proofing when used with 150 mm in place insulations adds to the cost effectiveness of the process (BRE 2003). The draught proofing and insulation processes require the use of already available or recycled materials reducing the overall energy consumptions (EST EEBPH 2003). The insulation process is carried on the walls and the floors to effectively reduce energy consumption in the buildings. A typical example of the heat loss directions are indicated in figure 7 below, with table 2 showing the specification requirements.
The specifications have the details of the surface requirements, wall, windows, roof, door, and floor requirements
Figure 8 below shows the end elevation of the insulation requirements which form airtight envelopes, the insulating envelopes, and the crucial joints that could be used to effect thermal bridging within the building.
New studies indicate the building regulations to have tightened with insulation and draught prevention requirements being very strict. According to BRE (2005b), insulation required for a building should be 250 mm thick instead of the 150 mm previous requirements. The insulation requirements could be easily met because 60% of the houses in the UK with cavity walls not yet insulated by 2004, which make the process of insulating the buildings cost effective and energy efficient. That is in support of the need to renovate instead of the costly process of demolishing buildings to pave way for new constructions (EST EEBPH 2003).
A typical process of providing buildings with thermal insulations includes inserting insulations appropriately into the cavity walls and is estimated to reduce the heat losses from a building by 40% (EST EEBPH 2003).
Mathematically, heat losses from a building can be calculated based on the following formula (UCL 2007).
Heat Loss = Σ (U x A x dT)
The heat loss formula is a sum of the heat losses through the windows, doors, roof, and other leaks identified in a building. On the other hand, heat losses due to air variations inside a house are calculated using the following formula.
Heat loss = ρ x V x C x dT
In the context of the above formula, ρ is the density of the air expressed in kg/m3, v is the infiltration rate in kg/m3, and C is the specific heat capacity of the air expressed as kJ/kg K. When insulating a building, it is crucial to obtain appropriate materials that meet the standard requirements spelt in the UK policies on insulating materials (Dunster et al. 2008). Research has shown sprayed recycled cellulose, polystyrene beads, and blown glass wool to be among the most appropriate materials for insulations.
The procedures of inserting insulations into the cavity walls include correcting the poor distribution of injection holes, and other construction defects that might be in the cavity walls. The process requires use of extensive renovation techniques that includes upgrading windows, and the insulations applied both internally and externally to a building. Different buildings have different U-values with the old stock buildings having high thermal conductance in the range of 1–2 W/m2 K. Analytically, the old stock buildings can be upgraded to 80% efficient and compliance with the required standards (Eames, 2009).
Previous technologies provided poorly performing double glazed housing with a U value of 3-4 W/m2 K. the results included an increase in the draughts and consequently heat losses and high energy consumptions (UCL 2007). Because of much research in the area of insulations, improved technologies have provided better solutions by providing windows in the market with a U value of around 1.2 W/m2 K (Strathclyde University 2006). Additional benefits because of isolative renovations are the decorative enhancements provided on a building if it is deprived of its internal decorations in addition to improving the thermal performance. At times, on exceptional circumstances, external decorations are put at the side of the building or the rear of the building redeeming the solid walls which had been regarded as thermally irredeemable.
With the underlying social, environmental, and economic considerations, solid walls are an opportunity to tap on rather than a problem to solve. Research by UCL (2007) has shown that solid walls can provide better and economically viable insulations compared with cavity walls.
Different insulation methods satisfy the stringent energy requirements with the ventilation rain systems and the rendered insulation systems providing the best external insulations so far. The rendered insulation system uses mechanical means to insert the insulating materials into position. At times, an adhesive can be used to put the insulating material into position and reinforced into position using a finished rendered finish.
Guards that support the fabric of the building are provided by the external insulations with the insulations done with linings internally to enhance and improve the pace of work. Internal insulations typically involve inserting linings using plasterboards on a frame. The process of inserting internal linings is cost effective and thermally efficient and lies within the stipulated energy savings requirements. The demerits of this method include loss of floor space, thermal discontinuity, and disruptions when conducting the whole insulating processes. Instead of the disruptive process of refurbishments, retrofitting is recommended especially for the floors of timber framed houses. According to studies “ carefully documented retrofit of four representative houses in the York region of the UK” (Bell and Lowe 2000), the installation of “new window and door wooden frames, sealing of suspended timber ground floors, and repair of defects in plaster reduced the rate of air leakage by 60–70%” (Bell and Lowe 2000).
The study showed that when both methods were combined of insulating the houses from the inside and the outside, and insulating windows and doors and using other appropriate insulation procedures, a significant reduction of heat requirements in this case, 35% was realized. The findings further indicated a 50% reduction in energy requirements and a 35% reduction in energy consumption using such houses. Dunster et al. (2008) have shown a significant improvement of the air quality despite an increase in humidity happens in houses that have not been insulated. To slow the rise in humidity levels, research studies recommend the use of old glazing (Fricke 2008). The above study has focused on the methods that have been used to reduce energy usage in buildings in the UK. The study is not exhaustive and there are recommendations for further studies in this area to provide a comparison between new buildings and renovated buildings (Fricke 2008). However, because the study is explores the rationale of refurbishments in place of demolitions and rebuilding of new structures, the study further undertakes to determine the best and new industrial methods of retrofitting old buildings to justify renovations instead of demolitions.
Modern Emerging Retrofit Building Fabrics
Literature on renovations by insulating old buildings shows that insulations on average cause walls to surpass the 60 mm width of thickness (Eames 2009). If insulations are evenly distributed on walls, the need for regular maintenance increases complicating the eventual structure of a building, higher load bearings, and a net loss of floor space. The demerits of insulations have compelled for the research and development of new insulating materials, which have lower thermal conductivities leading to improved energy performance (Eames 2009).
To address the problems and demerits of old building materials, research and development has led to industry standard materials that comply with required energy needs. Typical examples include aero gel, which is a gas filled material providing multiple insulation layers consisting vacuum and transparent materials. Among the materials discovered for use is Aerogel (Fricke 2008). Aerogel is the single most material with the lowest thermal conductivity of less than 0.012 w/mk and high thermal insulation properties. The material has the capability of withstanding loads 2000 times its own weight, adding further to its suitability for the construction industry. In comparison with traditional materials, only one tenth of aerogel can be used to cover for what a traditional material could be used for refurbishments (Houri 2010). That makes the material much suitable for refurbishments. A typical illustration of the suitability of aerogel as a thermal insulation material is where 20 windows of pane glass have equivalent in thermal insulation capabilities equivalent to “a single one-inch thick window pane of silica aerogel” (Houri 2010). That is in addition to considering the fact that a single window without insulation causes a loss of 30% energy from a house. To achieve better thermal efficiencies, insulations with multiple layers are used to provide improved thermal efficiencies (Houri 2010). Table 2 below shows a typical example of detailed simulation and results showing the thermal behavior of the multi-foil insulated roof below. A typical example of one of these insulations is known as multi-foil films.
In this case “the material consists of layers of foam with interspersed wadding in a series of reflective layers” (Houri 2010).
In brief the temperature of the thickness, surface emissivity, thermal conductivity, and associated materials were researched and the results from the thermal behavior of the material tabulated above. A combination of convection and radiation provides the mode of heat transfer between the elements of the multi-foil. Low surface emissivity enables low heat transfer, a process dependent on the air layers between the foils (Eames 2009).
Table 2 above provides the technical details and requirements for a multi-foil insulated roof. The “thermal behavior of the multi-foil is based on the three modes of heat transfer of conduction, convection and radiation” (Fricke 2008). Fricke (2008) has agreed in their study that by use of a low conductivity conventional mineral fiber, a high level of thermal efficiency is attained in the building. To optimize the energy efficiency of the materials, the path length of the intermolecular collisions is restricted to reach a minimum thermal conductivity of air at 0.026W/mK. It is crucial to ensure long wave radiation of the foil is attained in the insulating material. It is important to reduce the matrix voids used in the material to reduce the thermal conductivity of the material (Fricke 2008). The technical specifications detail the material requirements, the thickness of the materials, and the thermal conductivity of the materials, surface emissivity, and heat transfer requirements. The table provided details of the nodes that aggregate the entire structure to optimize the efficiency of the roof and increase the thermal efficiency of the building. The roof can be optimized for solar energy usage including space heating to further reduce energy consumption and efficiencies.
Further optimization of solar energy is achievable using transparent materials which allow for 45% transmittance rate of solar energy. That is because the thermal conductivity of transparent materials is below 0.2 W/m2 making the materials quite suitable for insulation purposes (Fricke 2008). Different materials with optical capabilities and curvature structures provide excellent transparent insulating materials for houses. That optimizes heat transfer despite the problem of controlling overheating inside a home in addition to associated costs (Baetens 2010).
To counter the above problems, GFPs (gas filled panels) have been used to reduce thermal conductivity and convectional currents using air and other types of heavier gases in the spaces Armin 2005). These barriers, as already mentioned provide low thermal emissivity with a baffle structure used to reduce heat movements because of radiation and convectional currents. Baetens (2010) has done many comparisons between vacuum and vacuum insulated materials. According to Baetens (2010), vacuum insulations provide a much better insulation implication compared with other conventional forms of insulations (Hinnells 2008).
A multi-foil structure can be modeled to consist of 19 layers with appropriate nodes included based on table 2 above. A thermal conductivity of mineral wool (0.04W/mK) was assumed in the study. If an aerogel thermal insulation layer of.012W/mK with a thermal conductivity and air with thermal conductivity of 0.026W/mK is used in the foam and wadding layers, a structure is created. The structure with multi-foil insulation provides negligible thermal conduction because of the narrow layers and a heat coefficient of assumed in the case to be 25 mm with an inclination of 450. The resulting structure has reflective films with an emittance with a 0.02 thermal conductivity and the foam layer having an emmittance of 0.012W/mK that is equivalent to a polished surface.
The performance of the above structure is core thermal conductivity of 0.04W/mK with the heat transfer between the multi-foil being a combination of radiation and convection. In this case, the heat transfer in the radiative mode is low because of low surface emmittance showing the effectiveness of the multi-foil as an insulating material to be dependent on the thermal conductivity of the air between the foils.
A research by Baetens (2010) has shown vacuum insulations to provide much better insulating capabilities because it relies on the vacuum to increase thermal resistance compared with conventional insulations. Projections have shown the vacuum insulations to provide significantly high thermal resistance and better performance solutions in the market today (Fang 2010). With strict adherence to the thermal insulation regulations and adherence to policies, it is projected that a center U-value of 0.2 W/m2 K could be achieved with a panel having a thickness of only 20 mm (Fricke 2008).The material shows a thermal resistance of a factor of ten, which is more of an advantage when used as an insulating material. The insulating capabilities of a vacuum spaced material can allow the material to be used in restricted areas and even n floors (Armin 2005). It is possible to attain, with the use of vacuum spaced materials, a low u value using multiple glass panes, low emitting radiation surfaces, and low heat resistance surfaces coupled into glazed panels. The use of high thermal performance materials has significantly improved the market demand of such materials in the building industry and especially for refurbishing old stock in the UK (Fricke 2008).
Building Services Equipment with High-Energy Efficiency
Once a house has been refurbished, there is need to ensure high thermal efficiency of the equipment used in the house to reduce greenhouse gas emission effects. The underlying rationale is to reduce energy consumption by electrical appliances which are estimated to consume 30% of the domestic electricity consumptions and 19% the total electricity consumed globally (Houri 2010). It is crucial to reduce energy consumption by refurbishing buildings to reduce the effect of waste products from energy usage. That is because, overall, poorly designed houses positively contribute to higher energy usage, with the consequent release of greenhouse gases because of low and poor energy efficiencies in the buildings. It is crucial to note that domestic energy usage can be reduced by 80% by a combination of measures which include using transparent lighting in homes, and additional energy control measures, and renovations as already discussed in this paper (Hinnells 2008). It is possible to achieve high energy savings by eliminating wasteful appliances such as incandescent lights that only convert 5% of the incident electricity into light and the rest being wasted. Replacement of the low efficient high energy lamps is a secondary option of reducing greenhouse gas emissions as already indicated above (DECC 2009). One of the methods identified to contribute positively to energy savings include passive lighting methods.
Studies show that passive lighting methods provide energy savings, enhance daylight penetrations, and improve visual aids. One of the most popular passive energy savings methods is the passive sunspace solar which provides low energy feature that should be used in refurbished buildings. Despite the uncertainties associated with the passive sunspaces, other studies have shown and recommended sunspaces to provide significant energy savings especially during winter. That is in addition to the recommendation to use aerosol as a thermal insulating material during winter across the UK (Kalina 2010).
Other passive techniques include use of fans and painting the roofs in each room to improve heat reflectivity. To prevent solar radiation in the process, the use of external shutters is recommended avoiding the entry of solar radiation that could cause heating in the home (Kalina 2010). It is important to substitute floors with carpets in refurbished buildings that expose the cooling effect by the timber frames. That includes the use of green roofs which minimize heat diffusion into the through roofs. The green roofs have an uptake of heat through the plants causing the thermal infusion through the roofs to reduce significantly. In this case, overheating because of radiation is significantly reduced (EST 2010).
In addition to lighting, heating is another contributing factor to energy consumption in homes. A solid wall home without any insulation requires a high amount of heating compared with an insulated home (Badescu 2003). It is crucial to reduce the amount of energy used in heating homes to reduce greenhouse gas effects. It is estimated that 80% of the total energy consumed domestically is for heating purposes with an household using 40% of its energy supplies for heating purposes in the UK (DECC, 2009). That adds to the need for refurbished houses. In addition to refurbishing a building, additional recommendations include optimizing the use of renewable energy. Typically, solar energy in this case “provides thermal energy for water heating and for lighting purposes” (TRCCG 2008). It is crucial in the process of selecting an appropriate solar appliance with high energy efficiencies. Typical examples include vacuum tube collector and flat plate collectors that occupy a 30% share in the market (TRCCG 2008). These techniques have been proven as effective in proving energy for heating water and for space heating.
Studies have further indicated the efficiency of using biomass as a renewable source of energy. Biomass reduces greenhouse gases because of the carbon lifecycle involved from fossil fuels that can be burned to produce greenhouse gases. The logical costs of supplying the biomass to homes are considerably low and appropriate for low income homes (CIRIA 2007). Biofuel systems have been identified as providing cheaper and energy efficient sources than combustible fossil fuels. The development of large biomass systems can provide one of the sustainable supplies of energy for refurbished buildings further minimizing the effect of greenhouse gas emissions into the environment (TRCCG 2008).
Another method identified as appropriate for use in refurbished buildings to reduce energy consumptions and greenhouse gas emissions is the use of heat pumps that are proved to be appropriate for use in domestic buildings. The most appropriate are air source heat pumps for refurbished or renovated buildings because of ease of installation and space requirements. That is in addition to more efficient heat pumps that have been developed in the recent past (EST 2010).
Adaption to Climate Change for Buildings in the UK
Research studies by TRCCG (2008) agree with facts that many buildings and especially the old stock have poor fabric and are characterized with overheating, and loss of energy reinforcing the need for refurbishment.
Once a building has been refurbished, it is crucial to insulate the buildings and provide appropriate ventilation to ensure energy efficient buildings in line with changing climatic conditions (TRCCG 2008). That is because most of the houses occupied today in the UK were constructed at a time when on adverse climate change had been experienced before. Studies by TRCCG (2008) show that in the 1990s, the effects of climate change started to take effect and with the UK registering the highest temperature of 38.5 degree Celsius in 2010, which was a temperature that had not been experienced before (CIRIA 2007). Additional consequences of climate change included an increase in the average summer heat waves to between four and sixteen days for many European Countries. Other consequences of climate change include falling of rainfall during summer and a rise in rainfall in the winter periods (CIRIA 2007). The resulting effects include predictions floods and overheating in homes. Heating standards indicate that when the sitting room temperature is 28 degree Celsius and 26 degrees Celsius for bedrooms, then the conclusion is overheating. It is therefore important to use passive techniques to keep temperatures low and reducing the effects of environmental air conditioning that could exploit significant amounts of energy (TRCCG 2008).
The Role of the UK Government for Sustainable Refurbishment
The government has played an active role in the refurbishment of old stock. Refurbishment has been identified as providing practical solutions instead of investing in the demolition and construction of new buildings. That is because refurbishment, as discussed above provides solutions that are economically, environmentally, and socially viable (National Audit Office 2008). Research has shown that refurbished houses, aside from providing energy saving solutions which result from the old stock energy inefficient building, the need to maintain the refurbished buildings persists. It becomes important for the government to play the major role of maintaining the refurbished houses. Estimates by the National Audit Office (2008) indicate that up to £3 billion could be spent annually for refurbishments.
According to the All Party Urban Development Group (2008), the government has identified and acknowledged the provision of incentives to implement energy efficient strategies. A typical example is the Capital Allowances Act 2001 designated as enhanced capital allowances (ECA). Under this act, the most efficient energy innovations attract a 100% tax free, facilitating the use of the technologies. That is in addition to the water efficient technologies that were introduced in 2003 including water limiting values and cartridges in addition to water harvesting energy efficient strategies (Department for Communities and Local Government 2006). It is important to note direct fiscal support by the Government to property industry with the capital expenditure on the new technologies written off as part of the incentive program (Department for Communities and Local Government 2007).
To address the environmental impact of refurbishments, a stamp duty tax levied on materials and technologies used for refurbishment with a series of rebates. These rebates help stimulate innovation and development of new technologies to address environmental impacts due to energy consumption and waste generation activities (PriceWaterhouseCoopers 2008).
Toward that end, government policy impels every department to conduct an environmental assessment known as the BREEAM of rating according to the set targets of SOGE, (Sustainable Operations On Government Estate), which provided standard measures to adhere to when carrying out refurbishments. SOGE was identified to be defined by stringent requirements, which are difficulty by the government to achieve (National Audit Office 2008). A practical assessment of 18% of the houses for compliance to the requirements showed 9% compliance. In the following year of 2007, compliance of 13% of the houses evaluated established only 8% to have complied with the stringent requirements. The compliance rate with the BREEAM standards was low and discouraging to the private sector. According to the Sustainable Development Commission (2008) report, the government could lose credibility in the refurbishment of the old stock of houses (Department for Communities and Local Government 2006).
Toward a sustained and practical approach of refurbishing the old stock and ensuring sustained levels of greenhouse gas emissions, the government provides economic incentives to the private sector to sustainably move the refurbishment process undergoing (National Audit Office 2008). The underlying motive is to reduce the greenhouse gas emissions through sustained refurbishment efforts to achieve higher energy efficiencies. In addition to that, the government has shown commitment to sustained efforts at refurbishments to achieve energy efficiencies as demonstrated in the capital allowances act 2001. Under the act, the most innovative technologies could be qualified for a 100% tax in the first year. Over 13,000 approved products have so far been developed under the proposal and can be accessed through a list provided. In this case, the government provided direct support to any construction industry geared toward energy savings technologies.
According to the PriceWaterhouseCoopers (2008) report, in the recent years the project has experienced accelerated government involvement in refurbishing buildings with recommendations for the use of direct and indirect tax systems. That is in addition to rewarding businesses that thrive on energy efficient systems. To further encourage Government involvement in the refurbishment of homes, recommendations have it that the Government further reduces taxation by 5% on domestic refurbishment projects aimed at reducing energy consumption and increasing energy consumption efficiencies. Brook Lyndhurst (2008) recommends that those who gain from such schemes display energy performance results at the appropriate and designated areas. Toward informing this study, a case study reflecting the benefits associated with empirical evidence on demolition and refurbishment is discussed in the following section.
Facts on Demolition
The following case study provides the rationale for refurbishment of old buildings as the best option for the UK government according to the social structure, economic, and environmental viability (Boardman et al 2005).
A report on the case study demolition of buildings reported by Mumford and Power (2002) and Boardman et al, (2005) demonstrated that demolitions provided viable approaches for reducing greenhouse gas emissions by 60%. Calculations showed the achievement of such a target could require three million demolitions by 2050. To a significant extent, the reports only focused on carbon emission reductions with many assumptions remaining unexplained in the papers. Among the assumptions in the reports included lack of focus on the social, political, and economic impact of demolitions of the old stock of buildings to achieve the projected 80,000 demolitions per annum. According to the report provided under the Sustainable Communities Plan, it was proposed that people adversely displaced by the recommended large scale clearances could be provided with alternative housing in addition to generous subsidies for the demolitions (SDC 2006).
The sustainable committee plan to increase the number of homes made in the 1990s to address the acute shortage of housing and eliminate poor quality housing had faulty objectives. According to ODPM (2004), the plan was to demolish 400,000 homes by carrying out large scale clearances with the current rate of demolitions way below the proposed plan. The proposed demolitions did not account for economic, social, political, and environmental problems associated with the demolitions. Recent evidence points out that large scale demolition are near impossible to execute given the underlying consequences (Houghton 2007). Practical examples of demolitions and environmental implications show the process to be unjustifiably expensive and out of context with reality. Among the consequences include depopulation of damaged areas because of demolitions, and increased house and property demands and costs (SDC 2007).
In that context, the report did not provide any research results on the carbon emissions and energy consumptions in the construction of the 250,000 homes (SDC 2007). That was in addition to the failure to provide statistical calculations of the carbon embodiment of the three million homes per year. The report further has many pitfalls by failing to establish the implications on the social fabric of the societies to be affected (SDC 2007).
Assumptions on the benefits to be gained from the demolitions included high energy efficient homes proposed for construction. It was projected a newly build home could be 25% more energy efficient compared with a counterpart old stock structure (OPSI 2008). The social, political, economic, and environmental challenges presented to the Environmental Change Institute weakened its position for large scale demolitions. The weaknesses are supported by the assumptions that the new houses could provide high energy performances. The homes build in the 1990s were assumed to provide a higher energy efficiency of 25%, with newer homes providing higher energy performances (OPSI 2008).
The report on demolitions and new constructions does not factor energy consumptions during the demolitions and energy consumed when renovating new materials to the required standards and transportation of waste materials and landfill processes (SDC 2006). In the report, the land requirements for new buildings and other necessary infrastructure, and environmental impact have not been discussed in the reports (Ireland 2008). In the report, no consensus and comparisons are made of high standard renovations and the positive implications of insulating the old stock buildings, besides lacking any report on the achievements that could be made on energy efficiencies and savings by 2050 (WWF-UK 2008).
From a technical perspective, the report is devoid of a discussion of the time frame a material lasts before replacement might be required. That is in addition to being devoid of the lifespan projections of the new structures, costs associated with maintenance requirements, and the waterproofing structures such as roofs and floors used in old buildings. The report lacks the essential information about the upgrade of the existing stock of buildings and the likely impact on old buildings.
Investigations by Power (2006) show that the half of the current expenditure on buildings is dedicated to renovations and further affirms the need to protect the existing stock because of resources are becoming depleted in the current economic recession in the world. The economic argument provides the rationale to ensure the current stock provides better options than demolition and construction of new homes.
Other studies indicate that people who occupy large homes find it expensive and impractical to heat large homes. Such homes, according to the report are occupied by the elderly who rely on the energy and greenhouse gas intensive heating from electricity. In the report, there is lack of support for the need to refurbish such buildings as they are easy to renovate (Ireland, 2005).
The biasness of the report by the Environmental Institute is indicated in the proposed demolition of the large buildings without the option of refurbishing the buildings to reduce energy costs and environmental impact due to new constructions. Each of the options either to renovate or demolish and construct new buildings, according to this study, should include clear cut research to draw conclusions on the best technique without basing the options on assumptions. In this case, the energy efficiency of the proposed homes provides crucial standards against the 40% estimates required by the Environmental Institute. According to Lararus (2002) studies which are in line with the CERP report, projections on the performance of homes for a sixty year period while newly constructed homes could take up to twenty eight years to acquire the energy efficiency levels provided by refurbished homes. Evidence by the UK Government Department for Communities and Local Government (DCLG) (2007b) in this case points to the energy optimization advantage provided by refurbished homes compared with newly build homes. A typical example is the ECO home in the UK which has attained 85% reductions in energy consumption because of implementing energy efficiency measures (WWF-UK 2008).
The Royal Commission on Environmental Pollution (RCEP) (2007) report provides evidence on empirical research studies which show that renovations provide, over a minimum period of ten years, significant energy reductions and reduced carbon emissions. In a period of twenty five years, the study shows highly embodied houses have the likelihood of higher energy efficiencies surpassing refurbished homes (Scottish Government 2007). In that case, embodied energy is the energy consumed directly for the refurbishment process and raw materials. In the context of refurbished houses, embodied energy is the sum of energy consumed in the whole process of the entire chain of energy consumed in the refurbishment process and other contributions on the materials used in refurbishment as shown in the chart below. It is crucial to note in this case that refurbishments and demolitions consume different amounts of energy and generate different amounts of wastes to the environment. At the apex are the energy fluxes in buildings summarized in the next hierarchy to consist of materials that are directly or indirectly consumed in the processes, construction that can either consume energy directly or indirectly, maintenance and demolitions and associated costs. The processes that are involved are shown in the chart below.
Research shows that it is practical to attain higher energy efficiencies can be attained in refurbished buildings if measures were including better demand management, incremental and high quality renovations using industry standard new materials, implementing the use of energy enhancing mechanisms, increased investment and provision of incentives for superior quality renovations, and use of low energy consuming methods in the homes. If the latter approach is adopted, the support by The Royal Commission on Environmental Pollution (RCEP) (2007) report for refurbishment of old buildings is assured instead of large scale demolitions of old buildings with the commencement of the construction of new structures (Scottish Government 2007).
Facts on Refurbishing Existing Buildings
A pilot program by the Germany government, ZukunftHaus, to install energy efficient procedures to 915 houses in a small number of rented flats across the country provides the basis for the rationale of refurbishment. The 34 houses used in the study were selected from flats built in 1978 (Boardman et al. 2005). Investigations revealed the houses were poorly designed and constructed and inherently energy inefficient. According to Lararus (2002), the refurbishment plan was to insulate using advanced techniques which included glazing, cladding, solar collectors, and energy efficient heating systems to address the needs for hot water (ODPM 2004). Results from the refurbished homes indicated an 80% reduction in energy consumption in addition to showing the energy efficiencies attained were almost double the current energy efficiencies of modern standard homes. This provide practical evidence on the techniques the UK government should adopt in refurbishing old homes, if more strict measures could be applied to attain even higher energy efficient homes (Houghton 2007).
A typical lesson to inform the study is the intensive program stared by the Germany government in 2007 to upgrade all the pre 1984 houses into modern high standard homes. The proposed upgrade on 17 million old stock buildings with 30 million dwellings is projected to reduce Germany’s overall carbon emissions by 40% come 2020 (ODPM 2004).
A parallel could be drawn on the UK’s Empty Homes Agency which was commissioned to renovate and bring back old empty abandoned homes into operation. To inform the approach for renovating the old and discarded buildings, the Empty Homes Agency conducted studies on old energy deficient buildings and new buildings against energy embodiments in both cases (Johnston 2005). The study involved use three old houses and six exemplar buildings. The old buildings were refurbished to energy efficient standards while the new buildings had been constructed by experienced contractors to the required standards (Ireland 2008). The aim was to explore the embodied energy for each of the two sets of homes to establish associated energy efficiencies over a 50 year line (Johnston 2005).
An analysis of the findings indicated the energy embodiment of new homes was 35% against the 7% for renovated buildings over a similar period (Johnston 2005). To ensure the results were not bias, similar houses were used with the same carbon emission rates. Observational results showed that the buildings that had been renovated had a 40% lower carbon emission rates while the 19th Century buildings were 20% efficient (Johnston 2005). Calculations based on energy embodiments in use of the refurbished old building were 194 tons per a home and new buildings were 174 tons per home (Ireland 2008). Refurbished buildings that had been performing poorly showed significant improvement in a 28 year period, better than newly build homes. When evaluated in a 50 year lifespan, the refurbished buildings showed similar energy performance with new homes. The new results radically deviate from the findings of the Environmental Change Institutes which shows that old refurbished buildings do not perform efficiently. Empirical results by the Empty House Agency have demonstrated that old buildings perform much better in energy savings contrary to the limits set by the Environmental Change Institute (Johnston 2005).
One other source that provides results that support the need for refurbishing old buildings is the English Heritage organization. The English Heritage (2006) shows that old refurbished buildings become poor energy efficient homes because of poor quality insulating materials (Johnston 2005). The organization established that old buildings with terraces were cheap to maintain compared with newly build homes. The old homes were identified as having less embodied with energy in its structural elements such as beams and bricks (Power 2006). The refurbished buildings were also established to be less costly to maintain refurbish. In addition, it was established that materials used for refurbishments were less costly and longer lasting, adding to the rationale for refurbished buildings. A refurbished home with terraces could provide higher energy savings because of the structural position of the walls contrary to the assumptions by the Environmental Change Institute. According to the English Heritage (2006) report, more terraced homes are being developed with the advantage of community heritage, preserving the social structures in place.
A thorough investigation and audit by the Building Research Establishment organization on energy savings on renovated buildings based on SAP ratings showed a 60% achievement on energy deductions when insulations were used on roofs and other sections of a building. Yates (2006) established that wider renovations of buildings in the community produced better energy performance results. That is because of better management standards of urban environments, and improved techniques of renovation and repair. On the other hand, houses that were renovated in 1970 have been identified to require reinvestment in refurbishments and advanced property management in the urban neighborhoods.
One recent study by the University College London on the technological viability of attaining a 60% CO2 reduction by middle of the century based on the analysis of findings from three household stocks was informing (Power 2006). According to the studies, results reported the viability of current technological to successfully achieve greenhouse gas emissions by 80% within the scheduled middle of the century. That is in view of insulating solid walls with the existing technologies and materials. The success could also be coupled by the underlying investigations on different materials, water, and waste materials and bet methods to use to enhance the performance of existing buildings. The findings based on the Germany case study reinforced the option of refurbishing old buildings with the viability of achieving energy savings and reduction of greenhouse gas emissions to the required standards (Power 2006).
The case study findings indicate such attainments were viable if the basic elements of the heating system such as roofs, doors, and under floors were insulated to required standards. The study recommends that up to 60% energy reductions could be achieved (Power 2006).
To reinforce the above findings which the British government could adopt, the projections to upgrade all social dwellings to required standards, a Decent Homes Programme was initiated. An average investment of £10,000 was provided for each home to improve the thermal comfort of each home, provide waterproofing capabilities for each home, and carry out basic repairs. A reports by the UK Government Department for Communities and Local Government (DCLG) (2008) shows that 70% of houses have been renovated to thermal efficiencies with an insignificant number falling into fuel poverty. The report has demonstrated that the need to carry out repairs, refurbishments, and other renovations to improve thermal efficiency of homes is crucial in attaining the energy efficiencies required and according to the established standards. Researchers including Power (2006) have established the vaibailtiy of renovations and the associated economic viabilities. These include use f insulating materials for renovations, insulating external and internal walls, insulating roofs as shown in this study, improving the insulation of floors using materials manufactured using enhanced and new technologies, using improved glazing, optimizing the use of space heating, and adding all these capabilities to a refurbished house.
The Negative Impacts of Demolition
It is important to demonstrate the negative implications of demolitions which have been recommended by some bodies while denounced by other bodies. That is in view of optimizing the best method of reducing greenhouse gas emissions. In view of the environmental concerns and the debatable impact of large scale demolitions on the environment, demolitions has largely been regarded a poor solution for the renewal of houses. Typical problems associated with demolitions and associated adverse impacts are listed in table 3 below.
|1. Demolition causes the loss of a property and the expenditure for a new replacement building. The compensation give to the property owner hardly covers the use value or replacement value of an existing building. This has proven to be a major problem to demolition in many housing market renewal areas, which makes is a big cause of disapproval for demolition in occupied areas, even in areas which faces major problems in energy efficiency.|
|2. Demolition produces damages to neighboring properties through disrepair and decline, as buildings proposed for demolition don’t draw any investment. Nearby properties decrease in value and there can be a domino outcome on local conditions.|
|3. It is hard to carry out neighborhood renewal by methods of demolition on a limited house by house basis. The physical outline of the majority of buildings suggested for demolition whether it is for streets or estates usually does not allow this method. Whole blocks, streets or areas are more often than not involved, and as a consequence viable properties are damaged. Our individual work in areas with major housing abandonment guides us to suggest a negative method to demolition, where merely the minority, abandoned and impractical properties were removed (Mumford and Power, 1999, 2002).|
The demerits tabulated above provide the basis for argument on the ineffectiveness of demolitions.
The Positive Impacts of Renovation
Many studies recommend renovations because of the positive impact of refurbishments. According to research studies, the clear benefits associated with refurbishments are listed below.
- Refurbished buildings retain the original structure of a building leaving the social structure, the environment, and existing infrastructure intact (Mumford & Power 1999, 2002).
- Solitary homes when refurbished tend to increase the worth of an area and increase attractiveness to investors.
- An analysis of time requirements for refurbishments shows demolitions for reconstruction of new buildings to be time consuming compared with refurbishments, which take less time. That is because refurbishments are done on existing layouts without the need for new developments (Mumford & Power 1999 2002).
- Demolitions and reconstruction of new buildings can take longer than a year, while refurbishments, despite being disruptive allows occupants to stay within their premises while the process is ongoing, which takes less time.
- No significant delays have been observed with the refurbishment process is ongoing. It is possible for the homeowner to stay within the home and insignificant disruptions due to weather are rare. That is partly because most of the refurbishment work is done in the inside of the home (ODPM 2006).
- The high possibility of little or no adverse effect on the environment provides clear cut evidence on the environmental value of refurbished buildings, increasing the appetite for investors to consider renovation as a positive activity. Investors tend to view refurbishments as an investment opportunity to bank on (Nao 2007).
- There is always need for continuous maintenance of old buildings. Renovations provide positive outcomes when done on old buildings because of the need for continuous upgrading on buildings according to new and emerging technology solutions. The outcome benefits are in the form of socially improved street conditions, flexible local transportation means for school going children and other users, improved aesthetical values, and enhanced social integration.
Studies have shown that even rich and privileged high income areas have low income neighborhoods which are constantly renewed to achieve the energy requirements set in the UK policies on housing and greenhouse gas emissions (Cook 2010). In the context of retaining the social structures in place and avoiding the disruptions and the adverse impact associated with demolitions of old structures, there is need for refurbishments which keeps the entire social structure intact. Typical examples of regions that have embraced refurbishments with positive results include Lancaster, York, Chester, among others. It is crucial to note that poorer towns opt for demolitions and new constructions because of lack refurbishments and continuous renovations (ODPM 2006).
Renovations provide value to constituted infill spaces. The infill spaces are defined by the little spaces that result from poor usage of land, change of use of the area or structure, and other additional changes that might be introduced and having space implications when effected. In most cases, the infill spaces do not provide any additional value to a property and renovations play a crucial role in providing value to the infill spaces (Cook 2010). These spaces also provide high investment risks to investors who see it as a wasted opportunity. In the studies by Power (2004), infill spaces have caused deterioration in the financial value of properties, increased the difficulty of planning on poorly managed and constructed spaces and buildings, and structural demerits associated with poor planning. To address the deteriorating situation, renovation of the infill spaces provides actual solutions on the ground. That is in addition to ensuring effective management of the existing property including neighborhood infrastructure. An effective management approach could revalue the property that had been written off and designated for demolition for renovation. Renovation therefore adds value to the otherwise worthless property.
Findings by RCEP (2007) have shown that household has decreased in size because of rising demand for housing and high population densities. Because of declining household sizes, infill construction provides industry standard solutions to the available land sizes and recommendations for the maximum size to be occupied by a given number of households.
Evidence shows that renovations provide economic benefits by spurring local economic growth by creating investment opportunities in the neighborhoods. That is in addition to providing acceptable standards for refurbishments that can be executed by small and medium sized companies. Such firms when contracted to do the refurbishments create job opportunities for the local population. It is also possible for renovation to be a source of new skills and technologies for the employed local residents besides providing improved economic activity in an economy adversely affected by recession.
A typical property renovation example is the Camden Eco House in North London. This is a multi-tenancy property that has been refurbished to a zero carbon emission level. The homes were built in 1850 and refurbishments have turned the property to an energy efficient structure by using 95mm mineral wool insulation on its internal solid walls. The results on the use of newly formulated insulation materials led to increased air insulation capabilities using double glazing and sash windows to enhance the energy performance of the old building. One of the benefits included exceeding expectations and defined standards by the English Heritage’s recommendations which recommended 50%-60% reductions in carbon emissions as shown in picture 1 below.
Camden Eco House, London
The project provided the baseline for carrying out other similar refurbishments because the use of local materials proved viable in energy savings and adherence to the UK standards. That was in addition to the learning point provided in the case study in the provision of refurbished housing. Other case studies have demonstrated the economic, environmental, and social rationale of refurbishing old buildings to the current energy efficient buildings. One such is the Mottingham House in South London shown in picture 2 below.
The above picture is an illustration of a part of the large estate constructions done in the 1930s. This construction were designed and fabricated with poor quality insulating materials with the roof containing 25 mm thick mineral wool insulation and a double glazed 100 mm loft wool insulation. In the above structure, a solid concrete floor was used to replace the suspended wooden floor (Cook 2010).
After a refurbishment of the above property, SAP tests conducted on the building to evaluate the energy efficiency revealed a rating of a 60% score, which was higher than the recommended 48% score. In this case, air tightness tests indicated superior performance compared with new structures. The superior performance of the building could be further enhanced by providing better insulations where leakages were identified such as in windows and other openings including the loft hatch. To further inform the best technique to use, an energy usage evaluation indicated a 209k Whm2/year and an estimated CO2 emissions rate of 70kg/ m2.
The overall strategy included using simple techniques of improving the existing old stock to achieve zero carbon emissions. The techniques used included insulating the building to minimize heat losses to the environment, installation and use of energy efficient water heating systems, installing lighting systems that are energy efficient, and use of technologically proven industry standard efficient micro-energy renewable energy systems for the purpose of reducing greenhouse gas emissions. Toward that end, the replacement windows and doors with appropriate energy saving products and air tight materials significantly reduced the energy usage in the buildings. The most appropriate material for providing effective insulation and improved thermal performance was phenolic foam used as a rigid insulation. The material provided effective internal and external insulation when used with a 95mm thickness. Further reinforcements of the insulating material at the rear with cladding external panels with a silicone finish using 220 mm thick rigid polyurethane boards provided enhanced thermal efficiencies. The results indicated significant alignment of the resulting u-values to the target u-values of “timber floor-0.2 W/m2K, External walls- 1.5 W/m2K, and pitched roof – 0.1 W/m2K”.
Tests conducted on the existing double glazed windows showed poor airtightness results. To optimize energy efficiencies, the windows were replaced with triple glazed windows with a U-value of 0.7 W/m2K. The renovation procedure included replacing external doors with new doors with a U-value of 1.0 W/ m2K. The use of skilled labor provided the essential workmanship. The constructors ensured successful renovation by keeping a detailed log of the external openings and the photographic archive. The MVHR system which extracts air from the bathroom and the kitchen supplying close to 9% of heat during winter is used at the inlet supply of fresh air during summer to raise the temperature of the air that is used in the bedrooms and the living rooms.
The results included significant reductions in space heating by 86%, which consequently reduced the residential heating bills. A typical result showed a reduction to 2,241 kWh per year from 16,696kWh per year. To further attain the efficiencies required, a conventional boiler was installed to supply the residents with half of the hot water energy needs. To optimize the performance of the boiler, it was installed facing the west and east directions on both sides of the pitched roof. An additional source of energy to bridging any electricity gaps was provided using photovoltaic panels installed to attain the 80% target. Intensive and extensive renovations were done to conserve water resources by installing a dual flush water system with a 2.4 litre capacity to the cisterns for two bathrooms. That is in addition to the use of the eco shower and aerated taps. An additional improvement of the system involved the use of gravity to feed the rain water harvests into a 300 hundred litre tank located at the stairs to optimize space. The tank was projected to supply the water needs in a significant household for flushing by drawing on the rain water.
The project was estimated to provide an upward of 65% financial savings for tenants, a benefit which correlated strongly with the savings in carbon emissions because of a reduction in energy consumptions for water movement and heating purposes. The current approach used by the Hyde Housing Association is to train occupants on the best method to occupy and live in the houses while ensuring measures are in pace to monitor the performance of the houses. That is in addition to providing reviews and induction trainings to the occupants and collecting their feedback for analysis and evaluation of the performance of the dwellings (Cook 2011).
A brief overview of refurbishments shows that refurbishing old stock leads to a gain in energy savings because of reduced property construction time, reduced project costs and time when compared with the full cost of demolishing and setting up a new building. In addition to that energy savings as carbon emissions because of demolitions, site preparations such as soil and materials preparations and movements, and stock retention resulting from better land usage and maintenance of the existing social structure. Refurbishments have been proven to provide embedded energy conservation, enabling the environment to remain intact, minimal use of materials that adversely affect the environment despite the demerits. The demerits associated with refurbishments include the complex work of renovations, demand for new technically engineered materials to optimize energy effectiveness, and continuous maintenance costs that make the refurbishment process costly.
The rationale for Renovations
The Sustainable Development Commission (SDC) has evaluated over the years the positive facts about renovation and refurbishments. In the long term studies, a number of critical issues that reinforce the need to refurbish instead of demolitions have been established. Among the critical issues include a high cost of energy savings as demonstrated in table 3 below. Costs associated with different sections of a refurbished building are detailed in table 3 below.
According to studies on the rationale for renovations, facts show that refurbishment and renovations provide one most important and single solution to enhancing the energy efficiencies of old buildings. Renovations are one crucial approach that agreeably complies with a cost benefit analysis as shown in the above table on the costs of different elements used in renovations. That is in addition to renovations providing comparably cheaper costs in the used materials with a feasible payback period. The feasibility of renovating old buildings is demonstrated in the market penetration feasibility analysis in the graph shown below.
In the graph below is demonstrations of different projections on the market position of the home energy efficiency measures are shown. In the graph, it is projected that the an aggregate of factors such as hot water insulation, cavity wall insulation, and others meet at the apex in the year 2040 when it is assumed optimal use of the factors as an energy efficient means of buildings is attained.
The above graph is projected on the assumptions that in the future, current and new energy efficient techniques and materials could have become scientifically proven and feasible. The research and development could be in tandem with the rise in demand for energy efficient materials. That is in addition to the need for the materials to be scientifically, proven for use toward optimizing energy consumptions and reducing greenhouse gas emissions.
Proposals to Help Upgrade Existing Buildings
In view of the current social, economic, environmental, and political challenges facing the UK, refurbishments, upgrading, and repairs of the old stock remain the single most crucial and effectively viable solution so far. That is because empirical evidence based on years of observations identifies refurbishments of the old stock as providing sustained methods of optimizing energy usage and environmental protection. The latter conclusion is based on examples such as VAT. When a new structure has been erected, it is VAT free, while attracting a 20% VAT on reinvestment and repairs. That is in addition to a decline in VAT by 5% if the building has not been occupied in more than three years. The VAT administration system also affects Government targeted regeneration, discouraging the need for demolitions and encouraging refurbishments.
The Government encourages demolitions by paying for demolitions in neighborhoods adding to the costs incurred when setting up new buildings and other infrastructure. An aggregate sum of £55,000 for the development of new infrastructure is incurred by the government besides the estimated costs of £17,500 – £35,000 incurred for demolishing old buildings. The total estimated costs of putting up a new building and associated infrastructure costs is estimated to lie between of £73,000 – £93,000. On the other hand, a redistribution of costs to refurbish a building on existing old buildings could cover a large number of buildings.
In conclusion to the above strategies, it is crucial to follow a conceptualized process constituting retrofit fabrics, use of energy efficient equipment, which is followed by micro-generation, and gradual zero carbon refurbishments. That includes refurbishments to high levels of thermal efficiencies on the internal and external walls with a space heating of 15 kWh/m2 yr while ensuring the total primary energy consumption of 120 kWh/m2 yr. The working should be based on certified standards with an average u-value of 0.11 W/m2k for the exterior walls, 0.13 W/m2k for the roof, and 0.086 W/m2k for the floor. The materials used for internal and external insulation, if technologically proven to standard, help retain heat energy generated because of internal activities such as cooking in addition to being retained from passive sources such as direct solar energy. The requisite use of emerging insulation materials to reduce the thickness leads to the reduction of insulting materials which otherwise could exceed 600 mm. The use of aerogel as another thermal efficient material is another strategy recommended for use with a low conductivity of 0.013 W/mk.
It is also crucial to use multilayered materials to enhance the thermal performance of the building. That is because of the reflective effects due to internal long wave reflections. The use of solar energy transmittance based on transparent materials which has achieved a 0.2 W/m2k thermal conductivity level such as optical materials. Gas filled materials is another source of material used to provide a barrier that envelopes baffles. It is possible to use the air and materials for low emissivity based on vacuum insulation panels. It is recommended from the studies that low lighting using LED to achieve 100 lm/w level of energy efficiency is used to replace low energy efficiency lighting systems. Other strategies include use of heat pumps to recover energy from domestic and non-domestic sources with research and development recommended in the field of heat pumps. It is technically proven that heat generated from electricity generation can be absorbed and tapped for use as a renewable source of energy. Other strategies include thermal storage to improve internal air quality, use of mechanical ventilation coupled with heat recovery techniques, micro-generation to increase the efficiency of refurbished buildings.
This study has weakened the position for large scale demolitions and construction of new structures with the underlying argument on energy embodiments and energy consumptions. The results from the literature and case studies show strong evidence and support for refurbishments, renovation, and continuous upgrade and maintenance of the old stock to achieve optimal energy efficient standards. The techniques could provide an effective path to greenhouse gas emission reductions cost effectively. While uncertainty is rife in the efficiency of the materials with some not scientifically proven including the cost effectiveness of renovations, practical implications of applying renovations. In the context of energy and environmental obligations, in addition to cost, economic, environmental, and political viabilities, demolitions remain largely disadvantaged by the energy requirements of the complete cycle of processing and acquiring materials for construction purposes. Typically, the number of demolitions and new constructions is an important greenhouse gas emitter and waste generator equivalent to 20% of the landfill materials generated. That is in addition to the energy consumption by worn out industry equipment, use of hand labor, transport of recycled materials and waste materials due to demolitions, and the inputs required for the construction of new buildings.
A crucial evaluation of the impact of demolitions is the demand placed on energy requirements for the movement of soil, landfill, and energy requirements for materials, energy maintenance, and the energy reuse for recycling purposes. That is in addition to meet the site construction, the construction process, and current energy expenditure. The consequences include higher energy demands and outputs as CO2 emissions, noise and dust which constitute environmental pollution, domestic wastes, and other wastes because of demolition and excavation activities. Other problems associated adverse environmental impact result from the land use, and other operational energy consumptions from the planning, construction, renovation, land remediation, and maintenance. Therefore a reform policy on refurbishments in place of demolitions could play a significant role in the decreasing energy use and carbon emissions to recommended levels by 2020.
The rationale is to refurbish old buildings by upgrading the stock to acceptable standards as outlined in the UK policies on carbon emissions instead of executing the energy intensive carbon emissions demolitions and associated constructions. Despite the missing link in scientific evidence on the efficiency of refurbishments and climate change, there is need for further studies to establish the scientific link and through research and development develop new energy efficient materials for refurbishments to reach the carbon requirement levels. With all well designed policies and implemented policies on energy efficient standards, it is possible within the projected time of 2050 to attain high energy efficient low carbon emissions from refurbished houses. Toward that end, refurbishment should be based on policies and other prerequisite support that is focused, based on technologically proven evidence, based on best practices, use skilled expertise in materials, construction, and methods to achieve low carbon production. It is recommended that the government facilitate the refurbishment process to help the construction industry meet the carbon emission target by 2050 or as defined in the government policies on carbon reductions.
Armin B, Andre M. 2005 Vacuum insulation in the building sector––systems and applications.
Barker, K 2006, Barker Review of Land Use Planning: Interim Report—Analysis. HM Treasury, London.
Badescu V 2003 Model of a thermal energy storage device integrated into a solar assisted heat pump system for space heating. Energy Convers Manage.
Baetens R, Jelle B P, Gustavsen A, & Grynning S 2010 Gas-filled panels for building applications: a state-of-the-art review. Energy Build.
Bell, M & Lowe, R 2000. Energy efficient modernization of housing: a UK case study. Energy and Buildings.
Boardman, B., et al. 2005. 40% House. Environmental Change Institute, Oxford.
BRE, 2003. BR457 Domestic Energy Fact File 2003.
BRE, 2005a. BR480 Reducing Carbon Emissions from the UK Housing Stock.
BRE, 2005b.Standard Assessment Procedure for Energy Rating of Dwellings.
Brook Lyndhurst (2008), Written Evidence to Inquiry 4: Climate Change and the Urban Built Environment: Greening Existing Non-domestic Buildings, APUDG, London.
CIBSE 2007, Guide L: Sustainability. Chartered Institution of Building Services Engineers.
CIRIA 2007, Building Greener. Guidance on the Use of Green Roofs, Green Walls and Complementary Features on Buildings.
DECC 2009, Digest of UK Energy-secondary analysis of data from the Digest of UK Energy, Department of Energy and Climate Change (DECC).
DCLG 2007, English House Condition Survey. Communities and Local Government, London.
DCLG 2006a, Review of the Sustainability of Existing Buildings: The Energy Efficiency of Dwellings—Initial Analysis.Department for Communities and Local Government, London.
Dunster, B, Simmons, C, Gilbert, B, et al. 2008, The ZED Book. Taylor & Francis, London. Eames P. Multi-foil insulation.
Department for Communities and Local Government; 2009.
EHCS 2004, EHCS Standard Tables, EE5a: Wall and Loft Insulation by Tenure.English House Condition Survey.
Elevate East Lancashire 2004, The Housing Market Renewal Pathfinder Prospectus. 2004.
English Heritage 2006, Heritage Counts: The State of England’s Historic Environment. English Heritage, London.
EST EEBPH 2003, Cavity Wall Insulation in Existing Housing. Energy Saving Trust, Energy Efficiency Best Practice in Housing.
Everett, B 2007, Saving energy—how to cut energy wastage. In: Elliott, D. (Ed.), Sustainable.
Fang, Y, Hyde T, Hewitt, N, Eames, P C, Norton, B 2010, Thermal performance analysis of an electro chromic vacuum glazing with low emittance coatings. Solar Energy.
Fricke, J, Heinemann, U, Ebert, HP 2008, Vacuum insulation panels—from research to market. Vacuum.
Harvey, L.D 2006, A Handbook on Low-Energy Buildings and District-Energy Systems (X387).CIRIA. Energy, Opportunities and Limitations. Palgrave Macmillan.
Hinnells, M 2008, Technologies to achieve demand reduction and micro generation in buildings. Energy Policy.
Houri A, Khoury P E 2010, Financial and energy impacts of compact fluorescent light bulbs in a rural setting. Energy Build.
Ireland, D, 2005, How to Rescue a House: Turn an Unloved Property into Your Dream Home. Penguin Books, London.
Ireland, D, 2008, New Tricks with Old Bricks. The Empty Homes Agency, London.
Ireland, D, 2005, How to Rescue a House: Turn an Unloved Property into Your Dream Home. Penguin Books, London.
Johnston, D, Lowe, R., Bell, M, 2005, An exploration of the technical feasibility of achieving CO2 emission reductions in excess of 60% within the UK housing stock by the year 2050.
Kalina, J 2010, Retrofitting of municipal coal fired heating plant with integrated biomass gasification gas turbine based cogeneration block. Energy Convers Manage.
Lararus, N, 2002, Beddington Zero (Fossil) Energy Development: Construction Materials Report.
Mansfield, J R & Pinder, J 2008, “‘Economic’ and ‘functional’ obsolescence: their characteristics and impacts on valuation practice”, Property Management, Vol. 26 No. 3,pp. 191-206.
Mumford, K & Power, A 2002, Boom or Abandonment: Resolving Housing Conflicts in Cities. Chartered Institute of Housing, Coventry.
National Audit Office 2008, Building for the Future: Sustainable Construction and Refurbishment.
ODPM 2003, Sustainable Communities: Building for the Future. ODPM, London.
ODPM 2004, Making it Happen: The Northern Way. ODPM, London.
Power 1993, Hovels to High Rise: State Housing in Europe Since 1850. Routledge, London.
Power, A., Mumford, K, 2003, Boom or Abandonment: Resolving Housing Conflicts in Cities. Chartered Institute of Housing, Coventry.
Power, A., 2006a, ‘Notes for HM Treasury on neighborhood renewal, housing repair and equalising VAT.
Power, A, Houghton, J 2007, Jigsaw Cities: Big Places, Small Spaces. Policy Press, Bristol.
PriceWaterhouseCoopers 2008, Written Evidence to Inquiry 4: Climate Change and the Urban Built Environment: Greening Existing Non-domestic Buildings, APUDG, London.
Rogers, R., Power, A, 2000, Cities for a Small Country. Faber and Faber, London.
Royal Commission on Environmental Pollution (RCEP), 2007.The Urban Environment. The Stationery Office, London.
Scottish Government 2007, In: Scottish House Condition Survey—Revised Key Findings 2007. Scottish Government, Edinburgh.
SDC 2006, ‘Stock Take’: Delivering Improvements in Existing Housing. Sustainable Development Commission, London.
Shorrock, L D & Utley, J I 2003, In: Domestic Energy Fact File. Building Research Establishment (BRE), London.
Strathclyde University, 2006. The Role of Built Environment Energy Efficiency in a Sustainable UK Energy Economy.
Sustainable Development Commission (2008), Sustainable Development in Government 2007, SDC, London.
The Energy Saving Trust. 2010. Getting warmer: a field trial of heat pumps.
TRCCG (Three Regions Climate Change Group) 2008, Your Home in a Changing Climate. Retrofitting Existing Homes for Climate Change Impacts.
on the Government Estate, TSO, London. Toolkit for Carbon Neutral Developments—Part 1.BioRegional.
Turcu, C 2005–2007. CASE Ph.D. Research on HMR Pathfinder, comparing the sustainability of demolition and refurbishment at LSE.
UCL 2007, Technical Options & Strategies for Decarbonizing UK Housing.BartlettSchool of Graduate Studies, University College London.
UK Government Department for Communities and Local Government (DCLG) 2008, Housing in England 2006/7: a report based on the 2006/07 survey of English housing, carried out by the National Centre for Social Research. DCLG, London.
UK Office of Public Sector Information (OPSI) 2008, Explanatory memorandum to the electricity and gas (carbon emissions reduction) order No. 188. OPSI, London. Web.
Wong I L, Eames P C & Perera RS. 2007, A review of transparent insulation systems and the evaluation of payback period for building applications. Solar Energy.
Yates, T 2006, Sustainable Refurbishment of Victorian Housing. BRE Press, Bracknell.