Since 2017, overheating has been recognised as a significant risk by the Climate Change Committee (CCC), but current regulations may not be doing enough to prevent it for the lifespan of buildings. Addressing this risk is fundamental to ensure resident health and satisfaction, especially since heatwaves in the UK are poised to be more frequent.
The latest CCC report states that there has been “little progress in addressing risks from overheating through building standards or retrofit”. In addition, the report has highlighted an increased risk of overheating in flats and energy efficient dwellings, with a study showing that all new homes in England have potential to overheat.
Planning requirements in places such as London, and the upcoming Approved Document [X], which aims to put overheating into building regulations, are steps in the right direction, but buildings can aim further than what is required by regulations by following the points below:
- Passive measures should be prioritised – reduced glazing ratios, increased window openable areas and shading. These will also benefit the energy strategy but should be balanced with daylight.
- Building design and their assessments should consider longer and/or harsher hot spells.
- Overheating must be considered in conjunction with other environmental factors such as noise and air quality – which can prevent windows to be open. This is already being considered in the upcoming Approved Document [X].
- Mechanical ventilation should consider summer bypasses and equipment noise.
- Low temperature and well insulated heat network piping design will benefit the temperatures in communal corridors.
In time, more onerous mitigation strategies may become necessary: CIBSE have recently received funding to re-assess the weather files that are used in dynamic modelling. With the recent IPCC report indicating that global temperatures are rising faster than required by the Paris Agreement, it would not be surprising if the weather files became warmer.