Home energy efficiency under net zero: time to monitor UK indoor air

The urgent need to reduce greenhouse gas emissions and the probable consequences of failing to do so are well established.1 In response, several countries have pledged to reach net zero greenhouse gas emissions by 2050.2 Achieving this target requires action in all sectors, including housing, which contributed a fifth of UK carbon dioxide emissions in 2020.3 The International Energy Agency expects “immediate and rapid improvements in energy efficiency in buildings, mainly from large-scale retrofit programmes.”2

Because the escape of heated air is an important source of energy loss,4 energy efficiency measures aim to reduce “unintended” ventilation. However, empirical evidence on the health effects of these interventions is limited. In particular, large scale longitudinal studies to assess the relations between energy efficiency, ventilation, indoor air quality, and health are lacking.5 Evidence from seven European regions suggests that people spend on average 56-66% of their time at home,6 a figure that almost certainly increased during the covid-19 pandemic. Personal exposure to air pollutants indoors may thus be greater than outdoors, and changes in overall exposure resulting from home energy efficiency measures may have important implications for health.7

In 2019, the UK became the first major economy to set a legally binding target of reaching net zero emissions by 2050,8 with an interim target of reducing UK territorial emissions by 78% compared with 1990 levels by 2035.91011 Improvements to the building envelope, such as wall and loft insulation, double or triple glazing, and improved airtightness, are expected to account for a substantial portion of the reductions in energy use for heating homes. New homes are to be …