Retrofit effectiveness: Evidence from a nationwide residential energy efficiency programme

Buildings in the EU are responsible for 40% of energy use, with approximately 75% of buildings classed as energy inefficient. Many energy efficiency technologies have failed to deliver on the promised savings. This paper measures the extent to which residential dwelling retrofit delivers real energy savings in Ireland using a unique dataset of whole-home energy use (n = 8,572 households) over a two-year period. It is one of the largest studies of retrofit using whole-home energy data for a general housing sample, who do not disproportionately experience fuel poverty. It uses whole-home energy data to capture potential fuel switching induced by retrofit. Finally, this study addresses concerns regarding self-selection issues associated with the decision to undergo a retrofit by comparing with a second control group of homes that received a retrofit prior to the observation period. Results following a generalised difference-in-difference methodology indicate that retrofits reduce energy use by 1,091 kWh/year, on average. However, the magnitude of savings depends on the measures installed. Further analysis suggests that retrofits represent better value for money when factoring in actual changes in energy use. This study highlights possible unintended consequences of retrofit policies that may hinder progress towards national energy efficiency targets.