How well do building energy performance certificates predict heat loss?

This paper evaluates the predictive power of building energy performance certificates on home heat loss. Improving the insulative capacity of residential properties is a policy priority in many markets, with building energy performance certificates serving as a benchmark. We exploit a rich panel dataset of high-frequency thermostat readings, coupled with data detailing weather and building characteristics, to identify an ex-post metric of heat loss. Our results show a significant effect of building energy performance rating on indoor temperature, a proxy for home heat loss. However, we do not find evidence of a distinct gradient in performance between building energy rating categories, as suggested by ex-ante estimates of home heat loss. The finding highlights that directly linking policy targets to a particular energy performance certificate standard can lead to an outcome that deviates significantly from what is anticipated.