HARD TO TREAT HOMES IN ENGLAND

Transcription

1 W07 Housing Regeneration and Maintenance HARD TO TREAT HOMES IN ENGLAND Adele Beaumont

2 Hard to Treat homes in England. Adele Beaumont. Housing Centre, Building Research Establishment, Watford, UK. Abstract. The English housing stock comprises about 21 million. Improving the energy efficiency in the domestic housing stock is a key priority to the success of several of the Government s current strategies including climate change, fuel poverty and the Decent Homes Standard. In this context, one sector of the stock has proved to be particularly problematic. Known either as Hard to Treat or Hard to Heat, these homes have been defined as: homes that cannot accommodate staple or costeffective energy efficiency measures such as loft insulation and cavity wall insulation and improvements to a heating system such as installing gas central heating. They may include homes that are off the gas network; homes with solid walls; homes with no loft space and high-rise blocks. In England, 9.2 million can be considered Hard to Treat, accounting for 43 the total stock. Solid wall and off gas network make up the largest component. In this paper we present the results of our investigation into the types of Hard to Treat homes in England using data from the English House Condition Survey (EHCS) which is an annual national survey of and their occupants. The technical solutions for improving the energy efficiency of this stock and the drivers and mechanisms available for funding such improvements in England are also discussed. Keywords: Hard to Treat; energy efficiency; existing stock Introduction. Improving the energy efficiency in the UK s domestic housing stock is a key priority to the success of several of the Government s current strategies including climate change, fuel poverty and the Decent Homes Standard. The UK s goal is to reduce its greenhouse gas emissions by 60% (from 1990 levels) by 2050 and the Government s Draft Climate Change Bill, published in March 2007, formally sets out it s aims to make this target legally binding. Homes are responsible for about 27 the UK s total carbon dioxide (CO 2 ) emissions (HM Government, 2006) and therefore reducing emissions from this sector is a key objective. Fuel poverty is the situation used to describe a household that has to spend more than 10 its income on fuel to maintain a satisfactory heating regime. In England in 2004, there were 1.2 million households in fuel poverty, ~6 all households. Meeting the targets set out in the UK Fuel Poverty Strategy (DTI, 2001), a subsequent progress report (Defra, 2004) and the Energy White Paper (DTI 2003) of eradicating fuel poverty in all vulnerable households in England by 2010 and all other households in England by 2016 requires the root causes of high energy costs (a function of energy inefficient houses and high fuel prices) and low incomes to be addressed. 1

3 The Decent Homes Standard is a government commitment to ensure that by 2010 all public sector homes meet the statutory minimum standard for housing, be in a reasonable state of repair, have reasonably modern facilities and services and provide a reasonable degree of thermal comfort. In the context of improving energy efficiency, one sector of the UK s housing stock is proving to be particularly problematic. Known either as Hard to Treat or Hard to Heat, these homes have been defined by the Energy Saving Trust (EST) as: homes that for a variety of reasons cannot accommodate staple energy efficiency measures offered under schemes such as Warm Front in England. They may include: homes that are off the gas network; homes with solid walls; homes with no loft space; homes in a state of disrepair; high-rise blocks; and any other homes where for technical and practical reasons these staple energy efficiency measures cannot be fitted (EST, 2004). These staple energy efficiency measures comprise the cost-effective fabric improvement measures such as loft insulation and cavity wall insulation and improvements to a heating system such as installing gas central heating. Given the construction history of the English housing stock, and the changing nature of the domestic energy supply over the years, it is not surprising that a large proportion of the existing housing stock falls into the category of being Hard to Treat (HTT). Research into the HTT stock in England has so far been limited to a few recent reports on HTT homes relating mainly to fuel poverty (Transco, 2002; Hine and Lafferty, 2004; Smith et al, 2005; Pett, 2004 and EEPfH, 2003). Interestingly, only one of these studies (Pett, 2004) attempted to quantify the number and types of HTT in the housing stock and this was limited to solid-walled and homes off the gas network. The aim of this paper is to present a detailed analysis of the numbers and characteristics of the HTT stock in England using data collected in the English House Condition Survey and to discuss the technical solutions for improving the energy efficiency of this stock and the drivers and mechanisms available for funding such improvements in England. The English House Condition Survey (EHCS). The English House Condition Survey (EHCS) is a national survey of and their occupants in England, commissioned by the Department for Communities and Local Government (CLG). The survey covers all tenures and the information obtained provides an accurate picture of the type and condition of housing in England, the people living there and their views on housing and their neighbourhoods. The survey is currently undertaken on a continuous basis with a sample of approximately 8,000 records collected each survey year (April to March) and it comprises three separate surveys: (i) the household interview survey, (ii) the dwelling physical survey and (iii) the market value survey. The interview survey is conducted with the householder and topics discussed include household characteristics, satisfaction with the home and the area, disability and adaptations to the home, work done to the property and income details. There are also different questions for each tenure, for example, renters are asked about responsibilities for repairs and maintenance and their satisfaction with the services they receive. The physical survey is carried out by qualified surveyors and provides detailed data relating to the physical nature of the 2

4 dwelling including construction type, dimensions, physical condition, windows, heating systems, heating fuels and insulation. The Market Value Survey is a deskbased exercise in which two valuations for each property are given; one is market value of the property in its current condition and the second is the valuation if any necessary repairs are undertaken. All the data collected by the survey are held anonymously and a public dataset is available on request from the CLG. The work presented in this paper has used a dataset comprising three single years of EHCS data ( ) in order to have a sample size large enough to be statistically reliable in the analysis of the HTT stock. This dataset comprised 25,088 survey cases, which, when weighted, represented a total population of 21.5 million and 20.8 million households. The difference between the numbers of and households is due to vacant. The reference point for this dataset was April What are Hard to Treat? An indicator for HTT has been created for the EHCS data using the information available in the physical survey dataset. Four categories of were used as the starting point for defining the HTT stock, these being: Dwellings with solid walls Dwellings off the gas network Dwellings with no loft High-rise flats In each of these categories, specific criteria were developed to further refine the indicator as discussed below. Solid wall In the English housing stock, just over 4.6 million standing today were built before 1918 (20 all ); a further 3.8 million (18%) were built in the interwar period of ; 7.7 million (36%) were built between 1945 and 1975 and the remaining 5.3 million (25%) have been built since The availability of materials and machinery, the demand for housing and the housing policy at the time of construction has led to distinctive types of in the stock. Until the 17 th century houses in England were mostly built of timber frames, in-filled with wattle and daub or brick. In the late 18 th and early 19 th centuries, the Industrial Revolution led to the mass migration of workers into the towns and cities and an unprecedented demand for homes. Rows of conjoined houses known as terraces were the usual form of high density residential housing up until These houses were typically of 9 solid wall construction, either brick or stone, with a layout typified throughout the country of two storeys, each with two rooms and the possible addition of a basement, attic room or back extension (Muthesius, 1984). In the 1920s and 1930s housing boom, semi-detached houses, consisting of pairs of houses built side-by-side and separated by a party wall, were symbolic of the suburbanisation in England and were mainly built for owner occupation. This time also marked the shift to cavity wall construction as a means of reducing damp problems and reducing costs. After 1945, the housing shortages of the post war years led to ~650,000 pre-fabs and 3

5 system built houses being put up (Harrison et al., 2004). These houses, designed to overcome the labour shortages in the post-war period, were made up of parts manufactured in a factory and then erected on site by relatively unskilled labour. Prefabs were designed to be temporary structures, however many post-war system houses are still in use today, although they often suffer from poor thermal insulation and structural problems due the corrosion of the steel reinforcements in the concrete construction. Between 1950 and 1960, the construction of high rise blocks of flats, mainly for social housing, was used as a solution to land shortage and the rising demand for housing (see section below) however this form of construction lost favour in the economic crisis of the late 1960s. Construction in the UK since the late 1960s has been regulated by Building Regulations and the external components of the have had to meet thermal performance criteria. This has led to the predominance of insulated cavity wall construction for new builds since The graphs shown in Figure 1 show the age distribution of the English housing stock and the proportions of the different dwelling types in each age band. Pre Terrace Semi-detached Detached Bungalow Converted flat Purpose built flat - low rise Purpose built flat - high rise Post Number of (millions) 4

6 Pre Post Figure 1: Construction type by age in the English housing stock. The top chart shows numbers of (millions). The bottom chart shows the percentage of each type for each age band. Data from the physical survey form of the EHCS was used to determine whether a dwelling had solid walls. Both traditional 9 masonry walls and other non-traditional construction types such as single leaf masonry, >9 walls (e.g. thick stone walls), concrete walls (either panel or in-situ), metal or timber panels and some mixed wall types (e.g. where the ground and first floors were constructed of different materials) were designated as solid walls. It is not possible to determine cavity wall that cannot be filled (for example, because they are situated in an area of driving rain) using the EHCS data. A recent estimate of the percentage of unfillable cavity walls is 7 the unfilled cavity wall stock (Iles, 2007, pers. comm.). Off the gas network Currently in England, the cheapest form of domestic fuel is mains gas. The majority of the country has access to the mains gas network, however there are some areas to which this network does not extend. This is particularly common in rural areas, where the low density of housing and inaccessibility make it an unattractive proposition for gas companies to build a supply network. Safety considerations in high rise flats often means that a piped gas supply is not available in these. A proxy for off the gas network had to be derived for this work as the EHCS does not specifically collect information as to whether a dwelling is on the mains gas network. For this research have been defined as being off the gas network if: 1) there is no gas system present and 2) if there is a gas system present but it is not a mains supply. This necessitates some caution when evaluating this proxy. The data from the EHCS does not give an indication of how close a property is to the nearest gas mains i.e. there may be a gas supply running into a residential area but one particular dwelling has not yet been connected. This could result in an over-estimation of the numbers of off-gas, although the effect is likely to be small. Figures reported by Pett (2004) show that there were 3.1 million households in 5

7 England off the gas network in The number derived from the EHCS stock data is approximately 15% less than this. This is somewhat surprising as we would expect the survey data to overestimate the number of off of the gas network due to the proxy methodology used. It may be that there is a regional bias in the grossing which results in an underestimation of the number of households off of the gas network. For designated as being off the gas network but with a community heating system, the decision was made to re-assign these as non-htt as they already had an energy efficient heating system installed, or, if the heating system was old, at least the infrastructure was present to allow a more cost effective upgrade. No loft space In a typical English dwelling, as much as one-third of the space heating energy is lost through the roof. Insulating the loft provides a relatively simple means of effectively reducing this heat loss, however there are some for which the application of this measure is not practical. These are mainly in which either a loft is not present or in which the access to the loft is restricted due to the design of the roof. The EHCS survey form includes a variable about the type of loft present and also a variable describing the predominant roof structure. The determination of whether a dwelling had no loft was made using both of these variables. Dwellings with mansard, flat or chalet roofs were designated HTT (due to having no loft space in which to install insulation) if they were built pre Flat roofs, by definition, do not have a loft space; mansard roofs do have a roof space but it is usually very shallow and therefore difficult to access and chalet roofs may have some roof space which could be insulated but this level of detail is not reported in the EHCS survey. The age limit of pre-1990 was assigned as it was assumed that built after this date should adhere to building regulations and therefore have sufficient insulation. In addition to these criteria with loft conversions were also assigned as HTT if they had been converted pre-1990, for the same reasons that chalet roofs had been assigned. High rise flats The high-rise form of residential living, has its origin in the North American and European cities of the 19th Century as the industrial revolution led to the intensification of urbanisation. In the UK, the high-rise tower block is essentially a post World War II phenomenon, with the majority of residential towers being constructed between 1949 and In the post war reconstruction process the tower block was seen as a way of quickly and cost-effectively constructing large number of and the increasingly generous housing subsidies for ever higher blocks of flats provided a substantial inducement to clear central areas in large cities where land costs were highest and rebuild high rise flats (Rodger, 2000). Nowadays, high rise flats are notoriously hard to treat, with tower blocks in particular being seen as the pinnacle of the hard to treat pyramid (Hine and Lafferty, 2004). Developments built during the boom building years of 1953 to 1972 in particular have severe heating problems related to poor physical condition, maintenance and, for safety reasons, no gas. High rise flats in the EHCS data are defined as flats in a block at least 6 stories high. 6

8 Results. Numbers and characteristics of HTT in England. There are 9.2 million that can be considered as HTT in England, comprising 43 the total stock. Of these, solid wall make up the largest proportion with 6.6 million (31 the total stock; 72 the HTT stock). Off gas network make up the next biggest proportion with 2.8 million (13 the total stock; 30 the HTT stock). Table 1 shows the numbers of HTT in England, and breakdown by type, as determined from the EHCS data. Number of all Hard To Treat? Yes 9, No 12, Total 21, Solid wall Yes 6, Off gas network Yes 2, No loft space Yes 1, High rise flat Yes Hard to Treat stock Table 1: Numbers of Hard to Treat in England Some are HTT due to several of these criteria. For example, of the 31 the stock that is solid wall, 23 this is solid wall only, a further 3% is solid wall and off the gas network, 3% is solid wall with no loft, 1% is solid wall, off gas and no loft and the remaining 1% is high rise. These overlapping combinations have been amalgamated into five main categories that comprise the HTT stock. These are shown in Figure 2. Not HTT HTT Solid wall Off gas No loft Solid wall and off gas High rise Figure 2: Pie chart showing the proportions of the main HTT combinations in the HTT stock. It can be seen from the figure that that are HTT because they are of solid wall construction and/or that are off the gas network, which includes the 7

9 majority of the high-rise type, make up ~90 the HTT stock. In this paper, we have therefore concentrated our detailed analysis on these two types plus the high rise. Tenure. The English housing stock is predominantly owner-occupied with 70 all being of this tenure. Social housing makes up nearly 20 the stock with local authority housing comprising a slightly higher proportion compared to the Registered Social Landlord (RSL) tenure. The remaining 10 the stock is in the private rented sector. It can be seen from Figure 3 that nearly 84 the HTT stock is in the private sector, with the greatest proportion (68%) being in the owneroccupied tenure. Within tenures the private rented sector stands out as being of particular concern with 65 its stock designated as HTT compared to a total stock average of 43%. For the individual HTT types, there are proportionally more RSL that are off the gas network (and consequently fewer owner occupied ). The predominance of local authority owned high rise residential buildings can be seen in the high rise type. Owner occupied Private rented Local Authority (9%) RSL 623 (7%) Hard To Treat? Solid wall Off gas network High rise flat tenure tenure tenure tenure 6, , , (68%) (69%) (61%) (20%) 1, , (16%) (17%) (19%) (13%) (9%) (5%) (10%) (10%) Table 2: Tenure distribution of Hard to Treat (54%) (14%) 3 Owner occupied Private rented Local Authority RSL 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Solid wall Off gas network Solid wall and off gas High rise No loft Not HTT 8

10 Figure 3: Graph of tenure by HTT combination type. Dwelling type. The distribution of the different dwelling types within the HTT stock generally reflects the distribution of the different dwelling types across the whole stock (Table 3). There is a slightly higher predominance of terrace that are HTT which is a reflection of the solid wall construction that is typical for this type. Converted flats are significantly over-represented by HTT (88 converted flats are HTT), although this type does only comprise ~3 the total stock. The main reason for converted flats being HTT is that they are of solid wall construction. Just over 40 all high rise are off the gas network; low rise flats also have a fairly high predominance of being off gas. Only a small percentage of terraces and semidetached houses are off gas, reflecting the urban and suburban nature of these dwelling types. Terrace Semidetached Detached Bungalow Converted flat Purpose built flat - low rise Purpose built flat - high rise Hard To Treat? Solid wall Off gas network High rise flat type type type type 3, , (35%) (44%) (14%) 2, , (22%) (23%) (17%) 1, (13%) (10%) (20%) (7%) (9%) (15%) (7%) 1,249 (14%) 326 (4%) (8%) (2%) (2%) (5%) (24%) (5%) Table 3: Dwelling type distribution of Hard to Treat Dwelling age ,555 (100%) Not surprisingly, older are more likely to be HTT with 45 the HTT stock being built before 1919 and a further 20% built between 1919 and 1944 (Table 4). Pre-1919 are predominantly of solid wall construction with cavity wall construction only becoming common after the 1930s. The high proportion of pre-1850 being off the gas network is due to the majority of these being in rural locations

11 Hard To Treat? Solid wall Off gas network High rise flat age age age age Pre (8%) (10%) (12%) , , (20%) (27%) (10%) (3%) , , (17%) (22%) (4%) (1%) , , (20%) (24%) (8%) (6%) , (12%) (9%) (15%) (29%) (10%) (5%) (17%) (49%) (4%) (1%) (8%) (7%) (5%) Post (4%) (1%) (1%) Table 4: Dwelling age distribution of HTT Geographical location and type of area. (14%) (11%) (2%) 16 8 (3%) Due to the sampling size of the EHCS, the smallest geographical region the data can be analysed by is the Government Office Region (GOR). There are nine GORs in England, each built up of complete counties/unitary authorities and the numbers and types of HTT within each are shown in Table 5 and Figure 4. It is clear from Figure 4 that London has the highest proportion of HTT for a GOR which is due to the large number of solid wall. The South West and East of England regions have a particularly high proportion of off the gas network. In terms of types of areas, the two extremes of city centre and rural have the highest proportion of hard to treat although the main reasons for this differ; city centres have a large amount of solid wall and high rise whilst hard to treat in the rural areas are largely because they are off the gas network (Table 6 and Figure 5). 0 10

12 North East Yorks & Humber North West East Midlands West Midlands South West East England South East London Hard To Treat? Solid wall Off gas network High rise flat GOR GOR GOR a GOR (3%) 26 (3%) 17 (3%) 8 (4%) (9%) 36 (8%) 26 (7%) 9 (5%) (10%) 32 (11%) 23 (7%) 7 (8%) (8%) 41 (9%) 32 (7%) 11 (1%) (10%) 42 (11%) 32 (10%) 12 (9%) (11%) 45 (9%) 26 (21%) 26 (2%) 0 1, (11%) 44 (10%) 27 (17%) 21 (2%) 0 1, (13%) 35 2,219 (24%) 71 (11%) 21 1,890 (29%) 60 (18%) (9%) 8 Table 5: Geographical location (GOR) of Hard to Treat (6%) (63%) 7 London South East East England South West West Midlands East Midlands North West Yorks & Humber North East 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% No loft High rise Solid wall and off gas Off gas network Solid wall Not HTT Figure 4: Hard to Treat dwelling types in each Government Office Region 11

13 City centre Urban Suburban residential Rural residential Village centre Rural Hard To Treat? Solid wall Off gas network High rise flat area type area type area type area type (5%) 73 (6%) 57 (4%) 17 (26%) 13 2,772 2, (30%) 60 (35%) 50 (15%) 9 (49%) 4 3,637 2, (40%) 31 1,145 (12%) (7%) (6%) 88 (40%) (9%) (5%) (5%) 54 Table 6: Type of area and Hard to Treat (26%) 6 (24%) (22%) 21 (0%) (14%) (18%) % 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% City centre Urban Suburban residential Rural residential Village centre Rural No loft High rise Solid wall and off gas Off gas network Solid wall Not HTT Figure 5: Type of Hard to Treat in each area type. Why does this HTT stock need improving? As discussed in the introduction, improving the energy efficiency in the domestic housing stock is a key priority to the success of several of the Government s current strategies including climate change, fuel poverty and the Decent Homes Standard. Energy efficiency and SAP ratings. In the UK, the Standard Assessment Procedure (SAP) rating is the recognised methodology for calculating the energy performance of. This rating is an 12

14 energy cost rating based on the energy costs for space and water heating and uses a standardised heating regime, standard occupancy and is independent of geographical location. SAP scores for the HTT stock have been calculated using the SAP 2001 methodology which has a scale from 0 to 120; the higher the SAP rating, the better the standard and the lower the running costs. It can be seen from Figure 6 that HTT with solid walls and those off the gas network have average SAP ratings below that of the whole stock average. Dwellings which are both solid wall and off the gas network perform particularly badly with respect to SAP. High rise, although notorious for being Hard to Treat and providing poor thermal comfort conditions for their occupants, actually have an average SAP rating of nearly 10 points above that of the stock average. This is due to their significantly lower space heating requirements, a result of their generally smaller size and low number of external walls resulting in a smaller heat loss area. 65 Mean SAP rating High rise No loft Solid wall Off gas network Stock Average Solid wall and off gas 20 Figure 6: Mean SAP ratings for the Hard to Treat types Fuel Poverty. The problems associated with installing cost-effective insulation measures in Hard to Treat homes have been recognised in the UK Fuel Poverty Strategy (DTI, 2001) and the subsequent Government s Plan for Action (Defra, 2004). However, it is realised that in order to alleviate fuel poverty in this sector, more innovative, and most likely less cost-effective, measures are necessary. The latest fuel poverty statistics published by the Government (DTI, 2006) show that there are 1.2 million fuel poor households in England under the full income definition. Of these, 1.0 million are vulnerable households, that is older people, families with children and those who are disabled or have a long-term illness. Figure 7 shows that of the total number of households in fuel poverty, 66% live in HTT home. 13

15 Not HTT 34% HTT 66% Figure 7: Proportion of fuel poor households living in Hard to Treat and non- Hard to Treat homes. Decent Homes. The thermal comfort criterion of the Decent Homes standard sets out the requirements for to have both effective insulation and an efficient heating system. Efficient heating is defined as any gas or oil programmable central heating; the insulation criteria depend on what heating system is installed but deal only with cavity wall insulation and roof insulation. Solid wall are therefore neglected under this component of Decent Homes. However, as of April 2006, the Fitness Standard criteria of the Decent Homes standard was replaced by the Housing Health and Safety Rating System (HHSRS). Although not a standard per se, the HHSRS has an excess cold criteria and a SAP rating of less than 35 (using the 2001 SAP methodology) has been established as a proxy for the likely presence of this hazard. This new criteria means that a significantly increased number of are likely to gain a poor HHSRS rating and the majority of these are likely to be HTT with solid walls. Energy Performance Certificates. From June 2007, all homes being sold will be required to have an Energy Performance Certificate (EPC). The certificates are a result of the Energy Performance in Buildings Directive (EPBD), an EU directive which came into force in January 2006 and will show the SAP rating of the dwelling, the dwelling carbon emission rate and the assessment will also provide suggestions for possible improvements to the dwelling. It is envisaged that the certificates will be a driver for the improvement of energy efficiency in existing homes and they could be a potentially powerful tool for improving the energy efficiency in the private rented stock when they become obligatory for landlords to provide in October Technical considerations for improving the HTT stock. As for any dwelling, the order of priority for energy efficiency improvements should first be to improve the building fabric and secondly to improve the heating systems. Our research has shown that there is still the potential to improve some of the HTT 14

16 stock using standard measures such as loft insulation, cavity wall insulation and more efficient gas and oil boilers. However, by far the largest savings will come from improving the building fabric of the solid wall and installing low carbon heating systems into the off gas. At the current time, the technical options for carrying out these types of improvements e.g. solid wall insulation, heat pumps to HTT are relatively untested and expensive in the U.K.. There may also be some particularly HTT for which these improvements measures are not feasible and therefore an alternative approach may be required, for example, integrating the use of renewables or developing district heating systems. Solid wall insulation. Solid walls can be insulated either externally or internally. External wall insulation systems consist of an insulation layer fixed to the existing wall and a weather protective finish that can either be a wet render system or a dry cladding system. Dry cladding systems can be more aesthetically pleasing than render as different cladding materials can be used however, they are usually more expensive. External wall insulation can be installed without any disruption to occupants, it can improve the look of aging facades and reduces thermal bridging, therefore minimizing heat loss. However, planning permission may be required and due to the high cost of installing this measure, it can have long payback times. Internal insulation can be either a rigid insulation board or insulation fitted between studwork. Disadvantages of both of these internal systems are that they involve considerable disruption for the occupants and can result in a significant decrease in room size. The advantages of internal insulation over external insulation are that it is cheaper and easier to install (it can be done as a DIY job) and maintains the appearance of the external walls. Considerations for external wall insulation (EWI) In theory all could be insulated with EWI except those listed or those in conservation areas and in which the walls are structurally unsound. In the U.K. there are some 300,000 individually listed residential buildings, and a further 1.2 million which are located in conservation areas representing in total about a quarter of pre-1919 (Science and Technology Committee,2005). Planning permission is required as it will change the outside appearance of a dwelling but facings are available which mimic brick/shipboard etc. although these are likely to be more expensive. Dwellings which are already rendered are unlikely to need planning permission and may therefore have less administration problems. Depending on the insulation type, between 80 to 120mm of insulation would be required to obtain the EST Best Practice U-value of <0.3 W/m 2 K. Special attention is required for the treatment of window sills, drainpipes, eaves and conservatories due to this additional thickness and therefore EWI can only be applied professionally. The attitudes of homeowners to the application of solid wall insulation to their dwelling is something that cannot be investigated using EHCS data. It is envisaged that some homeowners may be adverse to changing the external 15

17 appearance of their dwelling, particularly if it had certain characteristic features that were attractive. Installing external insulation on a converted or purpose built flat may be problematic as all owners/leaseholder would have to agree change the external appearance. Installing EWI in social housing should be more practicable than for other tenures as the social landlords have a greater obligation to improve their housing and they have routine maintenance programmes in place. Private rented could prove problematic as SWI is not cheap and private landlords have little incentive currently to improve their properties High rise flats would probably require insulation using a dry cladding system which is more expensive than traditional wet render. Considerations for Internal wall insulation (IWI) In theory all could have internal insulation Depending on the insulation type, between 80 to 120mm of insulation would be required to obtain the EST Best Practice U-value of <0.3 W/m 2 K. For small houses this would mean a significant decrease in the internal space available. Internal insulation could only realistically be applied on a whole-house level if a major internal refurbishment of the dwelling was planned. Alternatively it could be applied on a room-per-room basis, perhaps as a DIY installation, when rooms were being redecorated. IWI could be a better option than EWI for households living in converted flats and purpose built flats as it would not involve the whole block of flats to be insulated. However, these dwelling types (along with bungalows) typically have a small floor area (at least 50 type has a floor area < 60m) and adding the required thickness of IWI could significantly impinge on the available space. It should also be noted that even IWI is unlikely to be installed by all occupiers in a block of flats and from an energy efficiency perspective, installing EWI on the whole block would be the preferable option and possibly even more cost effective if carried on the whole block level. Heating improvements. The options cited for improving heating systems in off gas range from measures for individual properties such as installing high efficiency oil condensing boilers, biomass-fuelled boilers, heat pumps (either ground or air source) and solar water heating to measures more suitable to a community or district scale such as using independent pipeline companies to install a gas pipeline and community or district heating systems fuel by biomass or CHP. Oil-fired boilers are a well-proven technology with efficiencies comparable to gas boilers. However, the cost of heating oil is currently greater than mains gas and so may not necessarily alleviate fuel poverty plus the carbon intensity of oil is also greater than mains gas and so does not go as far in reducing carbon emissions. Biomass-fuelled boilers would only really be suited to properties that had the space to store the fuel i.e rural and those with a large enough garden. Locating a 16

18 supplier of a suitable fuel may also limit the applicability of this measure. Heat pumps in the domestic sector are an emerging technology in the U.K. and have mainly been installed in new build homes (Pither and Doyle, 2005). Community and district heating schemes offer significant potential to those living in hard to treat homes to reduce their fuel costs and, depending on the fuel used, cut carbon emissions. Community systems are inherently suited to densely packed housing areas such as flats or terraces. In practice it is likely to be far easier to install community systems into tenanted owned by one landlord. Opportunities for funding improvements in England. There are limited funding opportunities available in England for the installation of Hard to Treat specific measures. The UK Government s principal tool for improving the efficiency of existing homes is the Energy Efficiency Commitment (EEC) which will run until The EEC requires energy suppliers, as a condition of their licence, to achieve targets, set in proportion to the number of their customers, for energy savings. The targets can be achieved by installing energy efficiency measures in households, however, the method by which the target is reached is not prescribed. Various approved measures are permitted, such as improving insulation, installing boilers, and upgrading white goods and for each measure that is installed the supplier receives an energy credit. Not surprisingly, in meeting their targets the energy suppliers tend to focus on the lower cost solutions such as cavity wall insulation and loft insulation. Therefore, householders living in Hard to Treat homes tend to fall through the net currently. It is likely than in order to persuade energy companies to start carrying out the more expensive options such as solid wall insulation or installing heat pumps, the Government will have to apply uplift factors to the energy scores of these measures, or encompass these in the Priority Group obligation. Social landlords fund the necessary improvements to meet their Decent Homes requirements through a mixture of their core funding provided by Government, EEC funding and private funding that has been levered through stock transfer and private finance initiatives. As the SAP 35 criteria has only recently been incorporated into the Decent Homes standard, the implications for the additional improvement work likely to be required for Hard to Treat properties remain to be seen. Warm Front is the Government s main grant-funded programme for tackling fuel poverty. Grants are set aside for householders on certain state benefits, and the measures that are funded are the standard insulation and heating measures and therefore householders in HTT solid wall homes are not eligible for a grant. The Low Carbon Building Programme (LCPB) is the replacement for the previous DTI Clear Skies and Solar PV grant programmes. The programme funds a range of micro-generation technologies including: solar thermal hot water, ground source heat pumps, bio-energy, renewable CHP and micro-chp. In order to be eligible for a grant certain energy efficiency measures are a pre-requirement. These are to have 270mm of loft insulation, cavity wall insulation if applicable, low energy light bulbs and basic heating controls. This grant scheme should be a key route to obtaining funding for the improvement measures specific to HTT. 17

19 Conclusions. There are 9.2 million in England that can be considered HTT, accounting for 43 the total stock. Solid wall and off gas network make up the largest component. Nearly 84 this HTT stock is in the private sector; the private rented tenure includes the greatest proportion of HTT with more than 50% of this sector being designated as HTT. The two extremes of area type, urban and rural have the highest proportion of HTT although for differing reasons; the majority of HTT in urban areas are solid wall whereas in rural areas it is predominantly off the gas network. London has the highest percentage of HTT for a Government Office Region, due mainly to the large number of solid wall found in the city. In terms of energy efficiency characteristics, average SAP ratings and CO 2 emissions vary quite significantly between the different HTT types with the solid wall and off gas being less energy efficient than the stock average and high rise flats being generally more efficient than the average. As a sector, the HTT stock emits just over half of the total carbon emissions of the total English dwelling stock. Although there are no direct funding mechanisms or policies in place to deal directly with the HTT stock, improving the energy efficiency of these is likely to become a key consideration for several of the current programmes, namely energy efficiency, fuel poverty and Decent Homes. Priority for targeting should be given to with solid walls and/or those off the gas network, however, there are technical issues with the improvement measures that need to resolved plus the challenge of incentivising the private sector to take action will need to be met. Joined up thinking across the various government departments and funding programmes will be required in order to effectively deal with the problem. References. Defra, Fuel Poverty in England: The Government s Plan for Action. DTI, The UK Fuel Poverty Strategy. DTI Energy White Paper 2003: Our Energy Future - Creating a Low Carbon Economy DTI The UK Fuel Poverty Strategy: 4 th Annual Progress Report. EEPfH, Investigation of Local Authority Activity in respect of fuel poverty in Hard to Treat Homes. Report prepared for the Energy Efficiency Partnership for Homes by Impetus Consulting Energy Saving Trust Hard to Treat Homes Guide. Harrison, H., Mullin, S., Reeves, B., and Steven, A Non-traditional houses: Identifying non-traditional houses in the UK Hine, T. and Lafferty, E., Community Household Energy Modelling. A study of hard to treat homes. Report prepared for the Fuel Poverty Advisory Group. 18

20 HM Government Climate Change The UK Programme Muthesius, S The English Terraced House. Yale University Press. 288pp. Pett, J Affordable warmth in hard to heat homes: progress report. Association for the Conservation of Energy. Pither, A and Doyle, N Hard to Treat Group. UK Heat Pump Guidance. Energy Efficiency Partnership for Homes. Science and Technology Committee, Energy Efficiency, 2nd Report, Session (HL Paper 21I). Smith, W., Wu, An., and Pett, J Rising fuel prives: the challenge for affordable warmth in hard to heat homes. Association for the Conservation of Energy. Transco, Hard to Heat Homes. Report for the Fuel Poverty Advisory Group (24). 19