Background:

England, and the UK more generally, has a large burden of winter- and cold-related mortality/morbidity in comparison with nearby countries in continental Europe. Improving the energy efficiency of the housing stock may help to reduce this, as well as being important for climate change and energy security objectives.

Objectives:

To evaluate the impact of home energy efficiency (HEE) interventions on winter- and cold-related mortality/morbidity, including assessing the impact of winter fuel payments (WFPs) and fuel costs.

Design:

A mixed-methods study – an epidemiological time-series analysis, an analysis of data on HEE interventions, the development and application of modelling methods including a multicriteria decision analysis and an in-depth interview study of householders.

Setting:

England, UK.

Participants:

The population of England. In-depth interviews were conducted with 12 households (2–4 participants each) and 41 individuals in three geographical regions.

Interventions:

HEE interventions.

Main outcome measures:

Mortality, morbidity and intervention-related changes to the home indoor environment.

Data sources:

The Homes Energy Efficiency Database, mortality and hospital admissions data and weather (temperature) data.

Results:

There has been a progressive decline in cold-related deaths since the mid-1970s. Since the introduction of WFPs, the gradient of association between winter cold and mortality [2.00%, 95% confidence interval (CI) 1.74% to 2.28%] per degree Celsius fall in temperature is somewhat weaker (i.e. that the population is less vulnerable to cold) than in earlier years (2.37%, 95% CI 0.22% to 2.53%). There is also evidence that years with above-average fuel costs were associated with higher vulnerability to outdoor cold. HEE measures installed in England in 2002–10 have had a relatively modest impact in improving the indoor environment. The gains in winter temperatures (around +0.09 °C on a day with maximum outdoor temperature of 5 °C) are associated with an estimated annual reduction of ≈280 cold-related deaths in England (an eventual maximum annual impact of 4000 life-years gained), but these impacts may be appreciably smaller than those of changes in indoor air quality. Modelling studies indicate the potential importance of the medium- and longer-term impacts that HEE measures have on health, which are not observable in short-term studies. They also suggest that HEE improvements of similar annualised cost to current WFPs would achieve greater improvements in health while reducing (rather than increasing) carbon dioxide emissions. In-depth interviews suggest four distinct householder framings of HEE measures (as home improvement, home maintenance, subsidised public goods and contributions to sustainability), which do not dovetail with current ‘consumerist’ national policy and may have implications for the uptake of HEE measures.

Limitations:

The quantification of intervention impacts in this national study is reliant on various indirect/model-based assessments.

Conclusions:

Larger-scale changes are required to the housing stock in England if the full potential benefits for improving health and for reaching increasingly important climate change mitigation targets are to be realised.

Future work:

Studies based on data linkage at individual dwelling level to examine health impacts. There is a need for empirical assessment of HEE interventions on indoor air quality.

Funding:

This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 6, No. 11. See the NIHR Journals Library website for further project information.

Article history

The research reported in this issue of the journal was funded by the PHR programme as project number 11/3005/31. The contractual start date was in April 2013. The final report began editorial review in November 2016 and was accepted for publication in September 2017. The authors have been wholly responsible for all data collection, analysis and interpretation, and for writing up their work. The PHR editors and production house have tried to ensure the accuracy of the authors’ report and would like to thank the reviewers for their constructive comments on the final report document. However, they do not accept liability for damages or losses arising from material published in this report.

Declared competing interests of authors

Zaid Chalabi reports grants from the National Institute for Health and Care Excellence (NICE), the Natural Environment Research Council and the Department of Energy and Climate Change during the conduct of the study. Michael Davies reports grants from the Wellcome Trust, the European Commission, the Engineering and Physical Sciences Research Council (EPSRC), NICE, the Department of Energy and Climate Change and the Department for Communities and Local Government during the conduct of the study. Ian Hamilton reports grants from Research Councils UK during the conduct of the study. Emma Hutchinson reports grants from the Irish Government (Department of Communications, Climate Action and Environment) outside the submitted work. Anna Mavrogianni reports frants from the Natural Environment Research Council (NERC); the Engineering and Physical Sciences Research Council (EPSRC); the National Institute for Health Research (NIHR); the Adaptation and Resilience in the Context of Change (ARCC) network; the Energy Technologies Institute (ETI); the Department for Communities and Local Government (DCLG); and the Department for Environment, Food and Rural Affairs (DEFRA). She also reports personal fees from the Zero Carbon Hub (ZCH); the Greater London Authority (GLA); the Department for International Development (DfID); Vivid Economics; the Energy Saving Trust (EST); the Carbon Trusts; and non-financial support from Arup Group (London, UK) during the conduct of the study, outside the submitted work. James Milner reports grants from the Irish Government (Department of Communications, Climate Action and Environment) outside the submitted work. Christophe Sarran reports grants from the Medical Research Council, NERC and NIHR outside the submitted work. Phil Symonds reports grants from EPSRC and NIHR outside the submitted work. Jonathon Taylor reports grants from the Wellcome Trust and NIHR during the conduct of the study. Paul Wilkinson reports grants from NIHR (the Policy Research Programme) during the conduct of the study and grants from the Irish Government (Department of Communications, Climate Action and Environment), Wellcome Trust, EPSRC Global Challenges Research Fund, (former) Department of Energy and Climate Change, NICE, European Climate Foundation and Natural Environment Research Council outside the submitted work.