The Overheating Problem

Although it may not feel like it during the cold January days, overheating in buildings in the UK is an ever-growing problem. A key reason for this is the improved building fabric standards, which are designed keep the building warm in winter, but prevent a building effectively losing heat during summer.

Overheating is a complex issue that is affect by a wide range of issues, such as increased amounts of glazing on modern buildings which allow more solar radiation in, or lightweight constructions which are prone to large fluctuations in temperature. It is not even simple to define what counts as overheating in buildings, as comfort temperature levels can be subjective and vary in each occupant based on factors such as activity level, clothing, and humidity.

The problem of overheating in buildings is made worse in cities, due to the urban heat island effect, as buildings and man-made surfaces generally absorb more heat than the natural surfaces they replaced. With climate change models predicting an increase in UK summer temperatures, it is an issue that will only grow in its significance to building design.

Overheating in buildings causes a range of issues. Firstly, it has a negative effect on the health and wellbeing of building occupants, resulting in stress, lost productivity, sleep deprivation and even early deaths in heat waves, especially for vulnerable occupants. Secondly, in order to combat overheating, many designers rely on mechanical cooling devices, such as air conditioning, which can use large amounts of energy and contribute to global carbon emissions and climate change. This means that addressing overheating is essential in the design of high quality, efficient, future proof buildings.

In order to combat the problem of overheating in buildings, major developments within London are required to demonstrate how they have reduced overheating and reliance on air conditioning as part of London Plan Policy 5.9. Overheating is also considered within BREEAM as part of the ‘Hea 04 Thermal comfort’ credits. At JAW we can help you meet either of these requirements through our Overheating and Thermal Comfort assessments, which can be used to demonstrate compliance and to identify potential mitigation measures or design tweaks required to prevent overheating.