Temporal spillover of private housing energy retrofitting: Distribution of home energy retrofits and implications for subsidy policies

Abstract

Energy retrofitting of private housing is fundamental to reducing the environmental footprint of the building stock, and energy efficiency policies are based on assumptions of the effects of retrofitting, including those on further retrofitting, also called temporal spillover. No study has directly investigated the impact of energy retrofitting on future energy retrofits.Our results (N = 6402) show that respondents who completed energy retrofits in the past three years are significantly more likely to undertake new energy retrofits (IRR = 3.449). This is also true when controlling for demographic variables (IRR = 2.752), attitude and self-efficacy. Younger age, lower income, higher investment capacity, a more positive attitude, and higher self-efficacy toward retrofitting are associated with more energy retrofits.Since a strong temporal spillover effect is present in energy retrofitting, we suggest that locking in the energy building standard to a suboptimal level after partial retrofitting is not as great a challenge as previously thought. Moreover, due to the distribution of retrofits, the average number of retrofits undertaken is a misleading indicator of the trends in a nation's building stock, and subsidizing small scale-retrofits may provide major benefits for households' overall environmental footprint.