Comfort taking: evidence review

This report presents findings from an evidence review on ‘comfort taking’, a phenomenon that can occur following improvements to a home’s energy efficiency, in which the resident heats the home more than before the improvements. The review aimed to: estimate the extent of comfort taking explore the types of households more likely to comfort take identify the drivers of comfort taking identify how to mitigate it where appropriate DESNZ commissioned the review, which was carried out by London Economics. Comfort taking: evidence review Ref: RAF063/2122 PDF , 305 KB , 29 pages Comfort taking evidence review: analytical annex Ref: RAF063/2122 PDF , 211 KB , 15 pages London Economics (2024) RAF063/2122 Comfort Taking Evidence Review Completed by London Economics for the Department for Energy Security and Net Zero prior to the 2024 general election in the UK. As such, any references to government policies, commitments, or initiatives may reflect the stance of the previous administration and were accurate at the time of writing. Views expressed in this report are from the relevant research agencies, based on data collected from research participants and other evidence, and not necessarily those of the UK government. © Crown copyright 2024 This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gsi.gov.uk. Where we have identified any third-party copyright information you will need to obtain permission from the copyright holders concerned. 3 Contents Executive Summary __________________________________________________________ 4 Introduction ________________________________________________________________ 7 What is ‘Comfort Taking’? _____________________________________________________ 9 The estimated extent of ‘comfort taking’ _________________________________________ 10 Methodologies used to estimate the rebound effect ______________________________ 10 Estimates for the direct rebound effect ________________________________________ 14 Characteristics of households who ‘comfort take’ __________________________________ 15 Main drivers and motivations to ‘comfort take’ _____________________________________ 17 Mitigations to limit ‘comfort taking’ ______________________________________________ 21 Evidence gaps _____________________________________________________________ 26 Conclusion ________________________________________________________________ 27 Comfort Taking: Evidence Review 4 Executive Summary ‘Comfort taking’ is a phenomenon that occurs following improvements to the energy efficiency of a property (and corresponding energy bill savings). The resident takes advantage (either knowingly or unknowingly) of their more efficient home by heating it more frequently and/or to a higher temperature, rather than heating it to the same temperature as before. A Rapid Evidence Assessment (REA) was conducted to consolidate estimates of comfort taking, explore the types of households that are more likely to comfort take, and understand the drivers of comfort taking and any known mitigations to limit comfort taking where appropriate. The REA was conducted in March 2024. Through following a rigorously designed search and screening strategy, 28 academic papers were included in the analysis and two papers from the grey literature (i.e. high-level policy or institutional reports). Comfort taking can be a positive and desirable outcome, for example, where households could not previously achieve sufficient thermal comfort in their homes. Therefore, policy solutions designed to limit comfort taking should focus only on those households who could already heat their homes to sufficient levels for their needs. Findings The extent of ‘comfort taking’ The term ‘comfort taking’ is not widely used in the literature, therefore we consider the phenomenon of comfort taking to be synonymous with the direct rebound effect specific to the context of energy efficiency, heating, and thermal comfort. Therefore, the REA included papers that estimate the direct rebound effect specific to domestic heating. Direct rebound effects occur when improved energy efficiency in the home leads to increased demand for lower cost energy services. Evidence from the REA finds that the direct rebound effect generally occurs in domestic properties. However, each of the methodologies adopted in the literature to estimate direct rebound effects has caveats and limitations, and there is no consensus on the most appropriate methodology to estimate direct rebound effects. There are also differences in how direct rebound effects are defined. Due to the wide range of estimates and the methodological limitations, the REA did not draw conclusions about the size of the direct rebound effect. Characteristics of households

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