Tackling the climate and health risks of overheating in buildings

Research at UCL Bartlett has highlighted the risks associated with overheating in homes, including climate-change, health, wellbeing and productivity, leading to new policy and recommendations.

Overheating in buildings is one of the most important climate-change risks facing the UK, but it is one that is often overlooked.

The Bartlett’s Complex Built Environment Systems (CBES) group, led by Professor Michael Davies (UCL Bartlett School of Environment, Energy and Resources), has made important contributions to understanding how indoor overheating affects public health and generating evidence-based solutions. 

Using a range of analytical tools – from Geographic Information Systems mapping to artificial neural networks and building performance simulation – CBES researchers have examined how multiple determinants of indoor heat risk, including climate, the urban heat island effect, building materials, human behaviour, and social factors, impact overheating risk.

This allowed them to produce adaptable and scalable models which can predict overheating risk for a range of different scenarios.  

Raising public awareness of overheating risks 

Their research has been central in raising awareness of the risks to public health associated with overheating in buildings, and this in turn has led to new approaches to mitigating these challenges.  

High temperatures are known to cause several health problems, which can increase the risk of death particularly for the elderly or ill. In London, for example, population mortality starts to increase when the two-day average maximum temperature exceeds 24.8C.

Housing type has been found to impact on indoor temperatures, with new builds and flats found to typically be hotter than older or detached buildings, for example. 

An important climate risk facing the UK 

Every five years, under the 2008 Climate Change Act, the UK government is required to publish a Climate Change Risk Assessment (CCRA), outlining the main climate-related risks to the UK.

As part of the second CCRA, the Department for Environment, Food and Rural Affairs (DEFRA) commissioned an independent evidence report. CBES experts were asked to contribute, lending their expertise on a range of issues including overheating in buildings. Owing to the team’s input, the report listed overheating in buildings as the second most important climate risk facing the UK.  

The report recommended urgent action, noting that there are currently no regulations or incentives to retrofit existing buildings or develop new build developments to limit overheating.

It followed CBES findings that both policy and technological approaches are needed to ensure buildings are well-insulated for winter, yet sufficiently ventilated in summer to avoid overheating. It also acknowledged that future research might show how green infrastructure could reduce the urban heat island effect which can increase overheating problems. 

Moving policy and building regulations towards solutions 

The UK government’s response to the report was to endorse all of the report’s recommendations, including those related to overheating, meaning that the issues were finally being addressed in policy.

The UK’s National Adaptation Programme (NAP), which sets out the current and future government actions in response to climate change was updated in 2018 to include a new section devoted to overheating in buildings.  

The research informed the UK Committee on Climate Change’s recommendation that a standard of regulation be introduced to reduce overheating risk in new homes, and this recommendation was also included in the committee’s 2019 report UK Housing: Fit for the future?

CBES’s Associate Professor Dr Anna Mavrogianni also contributed to the 2018 AECOM-led research project on overheating risk in new homes, commissioned by the UK’s Ministry for Housing, Communities and Local Government, which informed its review of relevant Building Regulations.  

Together, the consultation, lobbying and policy discussions undertaken by CBES researchers has been essential in raising awareness of overheating risks and moving policy and building regulations towards solutions. 

Links

• Professor Michael Davies’ academic profile  
• Dr Anna Mavrogianni’s academic profile  
• Eleni Oikonomou's academic profile 
• Dr Phil Symonds' academic profile 
• UCL Bartlett School of Environment, Energy and Resources 
• The Bartlett, UCL Faculty of the Built Environment 
• The Bartlett REF 2021 

Image 

• Image credit: iStock / kev303