The project aim was to evaluate the impact that HEE interventions have on winter- and cold-related mortality/morbidity in England, including assessing the impact of fuel costs and subsidies.
The specific objectives of the study were to:
- use the HEED data for England, 2000–10, combined with national mortality and hospital admissions data sets and location-specific meteorological data, to quantify the effect that the HEE interventions have on cold-related mortality/morbidity and other outcomes
- use a 35-year series of data for the major conurbations of England to assess interannual variations in cold-related mortality/morbidity and the degree to which they are influenced by fluctuations in fuel price and the winter fuel payments (WFPs), especially for vulnerable population groups that were defined on the basis of socioeconomic status, age and other parameters
- conduct in-depth interviews with householders and households to document long-term experiences and behavioural changes associated with HEE interventions, with a focus on the pathways linking HEE, well-being and aspects of FP, and to explore how health evidence of HEE interventions is, and could be, utilised in policy and advocacy activities, including evidence of inequalities
- use the evidence of objectives 1–3, in combination with evidence of costs and existing epidemiological evidence, to elaborate a model of health impact and to present and test policy options using a formal multicriteria decision analysis (MCDA) framework.
We also aimed to maximise knowledge transfer and impact through engagement with major stakeholders throughout the research process.
Our initial plan relating to objective 1 had been to carry out a postcode linkage of mortality and Hospital Episode Statistics data to the HEED to attempt a direct epidemiological analysis of the degree to which HEE interventions modify cold-related health risks. However, a subsequent analysis of HEED data combined with modelling of temperature changes suggested that the average HEE intervention was associated with an increase in indoor temperature of < 0.1 °C, an unexpectedly small effect for which the observable association with health outcomes would be further diluted with data aggregated to postcode level (see The impact of home energy efficiency interventions: 2002–10, Temperature changes). This seemed to place such health effects beyond the limits of detection using the proposed methods of data linkage and analysis. Therefore, with regard to objective 1, we altered our analysis plan to use an indirect approach in which assessed changes to the indoor environment were combined with more general epidemiological functions to derive impact estimates. In parallel, however, and with the support of the Administrative Data Research Centre for England, we continue to explore linkage analysis at the level of individual dwellings. This work will be completed and reported separately.
What this report contains
The report describes three main sets of quantitative analyses and the results of the interview (qualitative) study. The quantitative analyses include (1) epidemiological analyses, (2) studies of exposure and health impact and (3) the MCDA.
The three epidemiological analyses are described in Chapters 3 and 4. All are based on time-series (i.e. statistical regression) analyses of data for England, which allow the quantification of temperature-related mortality. The first analysis (see Chapter 3, Epidemiological studies) looks at the change in the burden of cold-related mortality over time since the 1970s and some of the reasons for change. The second analysis (see Chapter 4, Modelling) uses a longer time-series to explore the degree of life shortening in cold-related death. The third analysis (see Chapter 4, Modelling) examines evidence that dwelling characteristics determine, in part, vulnerability to heat-related death. All three analyses use daily or weekly empirical data on deaths and temperature.
The exposure and health impact modelling studies are also divided between Chapters 3 and 4. In Chapter 3, the analyses concentrate on changes to indoor temperature and air quality from energy efficiency. They are in part empirical [using housing data from such sources as the HEED and the English Housing Survey (EHS)] but also use building physics and other models to characterise the effect of HEE interventions on the indoor environment. These analyses specifically include a modelled estimate of the changes to indoor temperature and air quality as a result of the HEE interventions that have been installed in the period 2000–10 and also an estimate of the effect of those changes on health by using additional evidence on the links between temperatures, air quality and health. In Chapter 4, the health impact model is further developed and applied in a case study to compare the impact that HEE measures have with that of fuel subsidies.
Chapter 5 then considers the use of the MCDA as a decision support tool. The MCDA makes use of the outputs from the health impact model as its criteria for comparing policy options. It is a method of formalising the weight (value) given to different effects of HEE measures when deciding between forms of intervention.
The qualitative study is reported as a standalone analysis in Chapter 6.
Literature searches
Throughout the text, we describe background evidence that is germane to the various analyses and modelling methods. Literature on temperature-related mortality, and its relationships with housing, was obtained by a non-systematic search of the epidemiological literature through PubMed and MEDLINE In-Process & Other Non-Indexed Citations, with backward searches of references of recent papers. Separate searches were made of the buildings and energy efficiency literature for publications that were relevant to the indoor environment and for papers that were relevant to the methods and applications of the MCDA. In each case, the literature search was not aimed at a wider review of the state of current evidence but was targeted at specific analytical questions relevant to the chapter.
Public involvement
For this project, public involvement took two forms: (1) the involvement of organisations and agencies representing a range of stakeholder interests, including non-governmental and governmental organisations, to reflect their perspectives at local, national and international level; and (2) dialogue with selected members of the public through in-depth interviews.
Stakeholder groups were established that contributed to discussions of the design of the project and to the interpretation of its results through several workshops and other contacts. The groups’ input was sought, in particular, on policy focus, including questions relevant to the development of the MCDA. They included people from charities (including the Noncommunicable Diseases Alliance, Age UK, the Zero Carbon Hub, Energy Bill Revolution and the Joseph Rowntree Foundation), governments agencies [including the Department of Energy and Climate Change (DECC)] and the World Health Organization. These groups will also be engaged to assist in the dissemination strategy, as will members of the Advisory Group through representatives of local government and Public Health England. Age UK are assisting in dissemination through its nationwide network of local groups.
In addition, as part of the qualitative component of the study, we carried out interviews with local authority housing policy officers and councillors to understand councils’ activities with regard to HEE during recent years. Specifically, we sought to understand their role in local HEE uptake, the major HEE initiatives carried out by councils, factors facilitating/inhibiting uptake in the local area from their perspective, housing stock issues, tenure issues, vulnerable group issues, priorities regarding FP, sustainability and health, historical local spikes of interest in HEE and their collaboration with other organisations. We held extensive discussions with the directors at the following organisations to understand their roles in shaping HEE uptake and to understand the issues that they face: Groundwork, Care & Repair, Easton Energy Group and Bristol Energy Network, Talking Money, Green Doors, Centre for Sustainable Energy, Roundhay Environmental Action Project and Trading Standards.