Heating patterns in English homes and the risk of cold-related illness

In England, the morbidity and mortality rate is substantially higher during winter months. In the winter of 2017, 30% (49,000) more deaths occurred than in non-winter months. The main cause of excess winter mortalities is living in cold conditions. To combat this, the cold weather plan and National Institute for Health and Care Excellence guidelines recommend local authorities monitor their progress towards preventing deaths and illness associated with cold homes. However, there is no definition of when a household is at risk of cold-related illness in winter. Thus, the types of dwellings that are cold and the number of households at risk of cold-related illness remains unknown.

This thesis seeks to estimate the number and type of households at risk of cold-related illness in England and identify which households and dwelling characteristics correlation with cold living conditions. This is done in four stages: 1) Determination of the current heating practices in England, achieved through developing an indirect approach to calculating the heating practices of a household and applying the method to large data sets. 2) The development of a temperature-based framework, achieved through a thorough literature review, to define a cold home. 3) Estimation of the number and type of households at risk in England, carried out by analysing temperature data in 750+ homes for three heating seasons (2011, 2017 and 2018). 4) identification of factors correlated with cold living conditions and hypothesis possible causes, by considering households heating practices, income, energy efficiency, occupancy period and other relevant factors.

The heating practice study showed that, in England, the average household heats for 10.5hours per day between mid-October to the end of April with a thermostat setting of 21°C. Four heating schedules were identified: daytime only, two-peak (morning and evening), irregular or continuous. Heating practices varied notably and systematically depending on the household’s income, the number of occupants and the age of household members. The findings differed from those assumed in the UK Standard Assessment Procedure in three ways: the large variability in household heating practices, weekdays and weekends are heated similarly, and zoning is uncommon.

The literature review indicated that a home should be defined as cold if the living room had more than 25% of assumed occupied hours (17:00-22:00) below 16°C during the heating season (November to March). Temperature analyses demonstrated that the prevalence of cold homes in England reduced significantly from 17% (3.7 million) in 2011 to 11% (2.6 million) in 2018. However, over the same period, the number of households with older members living in a cold home more than doubled (75,000 to 191,000). The factors that were most closely related to the prevalence of cold homes included: occupants’ health, household income and the building fabric.