EPCs 'do not assess older buildings fairly'

Energy Performance Certificates may be doing older buildings a huge disservice.

The Society for the Protection of Ancient Buildings says that standard calculations under-estimate the thermal performance of traditional walls.

In some instances, says SPAB, heat loss through vernacular materials is up to three times lower than expected.

Its research says that the miscalculations could have negative consequences as it may lead owners to disproportionate energy saving interventions that may not only be unnecessary, but harmful to the fabric of a building. 

SPAB’s report suggests that 79% of the traditionally built walls sampled – including walls of timber, cob, limestone, slate and granite – actually perform better than expected.



Jonathan Garlick, SPAB technical officer, said: “Amazingly, this research has not been carried out before in England.

“Accepted theoretical performance figures have long been used as a standard base measurement when old buildings are being up-graded, altered or even assessed for EPCs, but are they correct? We believe our results prove that they are not.

“We appear to be actually underselling the thermal performance of our old buildings by not fully understanding them.”

“Energy efficiency is becoming the key issue for people working with historic buildings. If we aren’t basing our approaches on the right figures to begin with, then we could, unintentionally, be doing untold, invasive damage.”


Another study, by English Heritage, is currently looking at the thermal performance of single-skin brick construction, the type of walling system used in properties until about the 1930s.