Many organisations and local authorities are searching for a way to measure their progress towards a net zero built environment. In the domestic sector, every home has an Energy Performance Certificate (EPC) which gives an Energy Efficiency Rating between 1 and 100. It might therefore seem like a good idea to use the EPC rating as a metric to drive lower emissions in both existing and new housing.
However, the EPC mechanism and its supporting calculation isn’t designed to do this and, furthermore, has failed to keep pace with a rapidly decarbonising grid. As of 2020, electricity emissions are 30% less than those associated with gas. But the EPC calculation still assumes that electricity produces more than twice the level of emissions. EPCs are also designed to be compliance tools which means that the supporting calculation has some necessary assumptions and limitations. The result is that using the EPC rating alone to try and drive energy efficiency is unlikely to have any effect.
To illustrate why, and to suggest an alternative, the Passivhaus Trust has produced a short paper which sets out how EPCs work, their limitations and what alternatives might produce better results.
Author: Passivhaus Trust
Publication date: April 2020