1.3. Energy efficiency retrofit in UK houses
Since 1970, estimates of the average UK home energy efficiency, as defined by the Standard Assessment Procedure (SAP) 20053, have risen from 17.6 SAP points in 1970 to 54.7 SAP points in 2010 and the mean heat loss coefficient of dwellings is estimated to have fallen from 376 W/K to below 286 W/K (Palmer and Cooper, 2013). This increase in efficiency has largely been attributed to the increased uptake in whole house heating systems, more efficient boilers, improved glazing, and loft and cavity insulation and fuel switching to electricity.
Data on energy demand and energy efficiency of residential buildings in the UK takes various forms. There are several publicly available datasets on the UK housing stock, ranging from large cross-sectional surveys on the overall condition of homes and their theoretical energy performance, as found in the English Housing Survey4 (EHS), to smaller most selective data sets from study surveys of home energy use (e.g. the CaRB Home Energy Survey (Shipworth et al., 2010)), or field trails that focus on particular dwelling or household features or technologies (e.g. the Milton Keynes Energy park (Summerfield et al., 2007)).
However, until recently, data that featured both energy demand and house characteristics at a population level among the UK housing stock was severely limited to historic surveys and small field studies. The most comprehensive and representative dataset that drew together information on energy demand and dwelling characteristics was the Energy and Fuel Use Survey (EFUS), a subset survey from the English House Condition Survey (EHCS) of 1996, which collected data on electricity and gas consumption of approximately 3000 households to measure energy efficiency of the housing stock and the potential for energy savings. This dataset is now over 14 years old, and does not necessarily represent how energy is currently used within dwellings, nor does it capture the effects of the last 10 years of energy efficiency programmes. A follow-up EFUS in 2001 was never released due to unsound weighting therefore making it unrepresentative (CLG, 2013). The recent EHS survey (i.e. 2011–2012) will include an Energy and Fuel User Survey, which will hopefully be of sufficient quality for analysis, but at the time of writing this dataset has not been released. Having repeat measure cross-sectional data on energy use with detailed dwellings characteristics is vital for providing context to small scale field trials and to track long term trends in energy performance levels and base lining energy use beyond the available window in this study.
The Government has prioritised investment in energy efficiency through a number of public and supplier-led schemes and programmes since the mid-1990s including: the energy efficiency standards of performance (1994–2002), Warm Front (2000 onwards), the energy efficiency commitment (2002–2008) and the carbon emission reduction targets (2008–2012). Recently, the government has set out the Energy Company Obligation (2012–2015) that will tackle priority households and fuel poverty along with the Green Deal (2012 onwards). The Green Deal is a departure from past efficiency programmes in that it is a market-based initiative to support energy efficiency improvements by providing loans to households to cover the upfront cost of a retrofit measure that is paid back through energy savings via the bill under a ‘golden rule’ whereby the payments should not exceed the energy savings (DECC, 2012c).
The successful delivery and uptake of efficiency measures in order to achieve the goal of reducing greenhouse gas emissions and tackle priority issues such as fuel poverty requires that policies are developed from an empirical foundation built on high quality data. In particular, continuous collection of such data is essential for the evaluation of past programmes and the development of future evidence-based policies. The development of HEED has in part been the exercise of reporting for government programmes (such as those detailed above) but has also drawn together other sources related to energy efficiency retrofits, such as heating system inspections and double glazing installers. As a result, HEED contains many (if not most) of the energy efficiency measures carried out under government programmes or through certified installers and therefore presents an opportunity from which to develop an energy efficiency evidence base for policy development and evaluation. 能源需求和家庭能源效率数据库英文文献和中文翻译(3):http://www.751com.cn/fanyi/lunwen_49241.html