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Monitoring and Evaluation of Local Authority Energy Efficiency Schemes: Phase Two - Research Findings

Descriptionto establish the actual energy consumption of the dwellings before & after upgrading & to determine the ways in which social factors have contributed to differences between estimated & actual savings.
Official Print Publication Date
Website Publication DateDecember 29, 1998
Development Department Research Programme Research Findings No 31(1997)
Monitoring and Evaluation of Local Authority Energy Efficiency Schemes: Phase Two Building Research Establishment, Scottish Laboratory
ISBN 0-7480-6210-6Publisher The Scottish Office
This summary presents the findings of the second phase of a study to monitor and evaluate local authority housing in which work was carried out under the 1991 to 1993 Scottish Office Energy Efficiency Initiatives In the first phase, the Building Research Establishment (BRF) used 'Energy Targeter", a standard assessment model, to estimate the energy consumption and C02 emissions before and after the implementation of energy efficiency measures in each scheme The main objectives of the second phase were to establish the actual energy consumption of the dwellings before and after upgrading and to determine the ways in which social factors have contributed to differences between estimated and actual savings.
Main findings
  • Before the upgrading, the metered consumptions, except those from communal heating systems, wee well below the values estimated in phase one of the study. The low metered consumptions are mainly explained by the widespread use of unmetered fuels, such as coal wood or bottled gas The tenants' expenditure on fuel may also have been limited by income as almost half were pensioners and most of the remainder received other state benefits. This explanation is supported by reports of condensation and dampness that were received from many of the tenants throughout the study, suggesting that internal temperatures were lower Than those assumed in the mode ling software.
  • After upgrading, many fewer tenants were using unmetered fuel and most of the metered consumptions were closer to the predicted value, but generally still somewhat lower As the tenants were generally unchanged. it is probable that the use of fuel is still limited by income.
  • In the three sheltered housing schemes with communal heating systems studied, the metered consumptions were much higher than the predictions. Although account was taken of heating to high levels and the heating of communal spaces, BRE were unable to resolve the discrepancies. This raises questions as to the performance of energy models for communal housing.
The objectives of the Phase Two study were :-
1. to establish the actual energy usage before and after improvements from an examination of fuel utilities' records;
2. to assess the actual savings attributable to the energy improvements and to compare these savings with the estimated savings established in Phase One of the study;
3. to assess householders' reactions to the improvements undertaken and their perceptions of the benefits achieved;
4. to determine ways in which social and other factors have contributed to differences between predicted and actual savings.
The project methodology involved obtaining data on metered fuel consumption from the 3 Scottish fuel utilities. Consumption data were collected for a period extending 12 months before and after implementation of the improvement measures.
In addition, a questionnaire-based household interview survey was undertaken of tenants in the improved dwellings. In total, 266 interviews were carried out in 17 schemes in 16 local authorities. The schemes were distributed throughout Scotland and included traditional, non-traditional, high-rise and communal housing.
  • The survey data suggest that, before upgrading, some tenants' expenditure on fuel was limited by income. This, combined with the high energy demands of poorly insulated dwellings with inefficient heating systems, led to cold conditions with widespread mould growth.
  • In most of the case studies, the metered consumptions after upgrading were slightly less than those predicted by the Phase One modelling. This suggests that the use of fuel is still limited by income. However, as the dwellings are now well insulated and supplied with cheaper fuels, more of the tenants are now able to afford to heat their dwellings to a comfortable level.
  • While there had been little, if any, reduction in the use of metered fuels after upgrading, the consumption figures mask a number of changes from unmetered to metered fuel. These figures were also affected by a shift from expensive on-peak electricity to cheaper off-peak electricity and gas, reducing the unit cost of energy to the tenants.
  • 85% of respondents felt that their dwelling was warmer and more comfortable after the upgrading, 36% felt that fuel was more affordable and 14% felt that it was less affordable. There was no evidence that the introduction of VAT on domestic fuel had affected the tenants use of fuel or their perception of its expense.
  • Condensation and mould growth have been greatly reduced. After upgrading, condensation was present in 16% of dwellings and mould in 12%. These problems tended to be associated with high levels of moisture production, old inefficient heating systems and poorly insulated walls. The incidence was about half in those dwellings with extract fans compared to those without.
  • The findings indicate that those using unmetered fuel are consuming significantly more fuel overall than the remainder. This may be explained by features of the construction - the dwellings using solid fuel are less likely to be flats - and occupancy those families using solid fuel are larger than those without - as well as the extra ventilation loss due to the supply of combustion air.
  • Most schemes which were not in rural areas and did not use communal heating used between 80% and 110% of the predicted consumption after upgrading. This can be explained by relatively small differences between internal temperatures used and those assumed in Targeter.
Lessons for future studies
Although accurate annual consumptions could be obtained from the metered gas and electricity data, many of the dwellings, mainly before, but also after upgrading, were using either solid fuel or bottled gas. Many dwellings in the study were in old mining areas in the Central Belt where solid fuel is more widely used than in that housing stock as a whole. Although the survey included questions on the amounts spent by householders on unmetered fuels after the upgrading, the results were not useful - very few tenants could make reasonable estimates of their spending. Using data from the much larger sample in the English House Condition Survey, it was possible to show that the consumption of these fuels was of the right order to account for the discrepancy between the estimated and metered consumptions in some of the case studies.
The provision of w early data proved difficult, or impossible, for the fuel utilities in some areas, causing de lay in the study. For some dwellings, where there had been a change of tenancy at the same time as the
upgrading, the fuel utilities did not accept the current tenant's signature as authorisation to release the data relating to the previous tenant's consumption. There were, therefore, a number of gaps in the data available from before upgrading.
In the Phase One modelling, a comparison was made between the unmodified dwellings and a specific set of energy efficiency measures or an individual measure such as cavity wall insulation. In practice, however, in a number of the case studies a comprehensive refurbishment had been carried out in the dwellings over a number of years including many more measures likely to affect energy use than were modelled in Phase One making simple comparison difficult.
The project results indicate that the measures taken by authorities were effective in terms of improving the energy efficiency of dwellings although savings were less than predicted. The findings suggest that when energy efficient upgrading is applied to unmodified local authority housing the benefits will be mainly taken as improved internal conditions because of income limitations of tenants. A significant degree of actual energy savings is likely to have been achieved but the quantification of this is hindered by difficulties in obtaining information on unmetered fuels used. Assessment of savings is also affected by the fact that the authorities' stock is in a process of constant upgrading and thus it can be difficult to attribute effects to particular measures. Some indication of the level of energy savings achieved by the measures may be drawn, however, from the fact that in the two areas where there had been little or no use of unmetered fuel before upgrading there were 14% and 19% falls in consumption.
Although global climate concerns provided the impetus for the energy efficiency initiatives, the objectives of the initiatives broadened during the process of their development to take account of social concerns. The study illustrates that targeting social housing for energy improvements is to target housing which, in some cases, may be using lower than adequate energy consumption at the outset and tends to support the shift in emphasis towards social needs. The results do, however, underline the challenge of reaching the level of energy saving necessary to meet global climate objectives.
" Monitoring and Evaluation of Local Authority Energy Efficiency Schemes: Phase Two ", the research report summarised in this Research Findings, may be purchased (price £5 per copy).
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This Research Findings may be photocopied, or further copies may be obtained from:
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