BRE Trust reveals the results of DEC data analysis
Display Energy Certificates are not providing evidence of real energy-efficiency improvements in public buildings, according to a data-analysis project carried out by BRE Trust. The project interrogated the DEC statistics of over 28 000 public-sector buildings. These certificates are a record of a building’s metered energy usage and associated carbon emissions over a 12-month period and compare them against established benchmarks to give a rating from A (best) to G (poorest).
Jon Mussett, principal sustainability consultant at BRE explains, ‘Energy used in public buildings accounts for 4% of the UK’s carbon emissions. Design standards are improving, but we need to demonstrate that this is resulting in improved building performance. This study found that the DEC ratings for some schools recently refurbished to higher energy-efficiency standards under Building Schools for the Future and the Primary Capital Programme appeared to be no better than average. If expected savings are not being made, we need to learn the reasons why. DECs are important because they measure the carbon emissions from real buildings as they are being used.’
The BRE study found that the benchmarks were appropriate and that DECs were generally giving consistent results. However, up to 9% of DEC data is unreliable as a guide to the energy and carbon performance of buildings because default ratings are being used. This is most common for job centres (17%) and academies (23%). A further 2% of DECs had values that were questionable in some way — such as 37% of A-rated buildings listed in the database with a zero rating.
With thousands of buildings now producing DECs for the second year, Jon Mussett says, ‘The Government should seize this opportunity to detect and measure trends in carbon emissions in different parts of the public estate to help inform future policy.’
