Rebound effects in residential lighting - conceptual psychological framework and empirical findings

Adopting energy-efficient products or services is generally regarded as an effective strategy to reduce energy demand. Rebound effects due to changes in behaviour, however, may render the actually observed energy savings lower than those expected from engineering economic analyses. Scientists generally agree that such rebound effects exist, but their size, relevance and explanation are controversially discussed. While economists focus on price and income effects, social or psychological factors have largely been neglected. In this paper, we, first identify possible psychological drivers based on psychological action theories. Then we combine qualitative and quantitative methods to empirically study rebound effects and their driving factors related to lighting in the residential sector in Germany. Our qualitative focus group discussions provide a detailed insight into the possible role of attitudes and personal as well as social norms as drivers of rebound behaviour. Our quantitative analysis is based on a representative survey and conceptually and empirically distinguishes between rebound effects due to the higher brightness and those due to the longer burning time of more efficient light bulbs. Limiting our analyses for reasons of homogeneity to the replacement of the main bulb in the dining/living room, we find that if the new bulb is more efficient than the old bulb, 57 % of respondents chose a brighter bulb and 35 % report an increase in the time of use. The analyses of the survey data confirm that attitudinal processes in the form of re-evaluations might play a role, but do not support the influence of norms.