Initial findings from the DCLG’s Review of the Sustainability of Existing Buildings suggest substantial energy savings – 7MtC/y – could be made by improving existing homes but the payback period for the various improvement technologies will come as a surprise to many.
The initial report concentrates on the energy efficiency of dwellings and says homes produced 41.7MtC in 2004, 27% of total UK carbon emissions. This will have to fall to 17MtC by 2050 to meet Government targets.
"This research suggests our existing homes and buildings could offer some of the most cost-effective ways to cut our national emissions over the next few years," said planning minister Yvette Cooper.
The report says that, even with accelerated build rates, around two-thirds of the homes standing in 2050 are likely to have been built around 2005 as new build represents around 1% annually. Improvements to existing buildings have radically improved their energy performance but improved insulation and heating efficiency can still deliver benefits.
But the financial payback period for such improvement estimated in the report will turn conventional wisdom on its head. The quick payback improvements are things like lagging hot water cylinders (6 months), cavity wall insulation (2.6 years), loft insulation (2.7 years), improved heating controls (3.4 years) and draught proofing (4.3 years). By far the worst is single to double glazing (97.6 years to payback) and other poor paybacks are solar water heating (54.7 years), photovoltaic energy (46.4 years), ground source heat pumps (12.8 years) and David Cameron’s favoured micro-wind (10.5 years).
The hardest to treat stock is homes off the gas network, those with no loft space, high-rise blocks and solid walled buildings. But less than 1% of the housing stock has three of these factors.
The report concludes a substantial reduction in carbon emissions can be made by using cost-effective technology.
Source:
http://www.communities.gov.uk/pub/373/TheEnergyEfficiencyofDwellingsInitialAnalysis_id1504373.pdf |