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Urban health

How overheating homes are turning the climate crisis into a health crisis

We’re supporting the Bureau of Investigative Journalism’s Hot Homes project, alongside the Google News Initiative, the Bill & Melinda Gates Foundation and Necessity.

People who live with long-term health conditions are more vulnerable to the effects of heat, including cardiovascular conditions and diabetes – with the temperature in their homes making it much harder to manage their health. 

Professor Anna Mavrogianni, a heat and housing expert from UCL’s Institute for Environmental Design and Engineering explains:

Prolonged exposure to high indoor temperatures, especially when there is no night-time respite from heat, can result in a range of adverse health effects, especially for the most vulnerable population groups – such as babies and young children, and older people or people suffering from cardiovascular, respiratory or mental health conditions.

Professor Anna Mavrogianni UCL Institute for Enviromental Design and Engineering

From early August to mid-September this year, 40 homes in the London Borough of Southwark – one of the hottest places in the UK – were fitted with temperature sensors.

The numbers they returned were stark.  

The temperature in every home in the study rose to at least 25 degrees Celsius – the maximum safe indoor temperature for London, as recommended by the World Health Organisation. Some homes experienced this increase for over a fortnight and alarmingly 10 homes recorded over 30 degrees Celsius. 

A resident who took part in the study said their home was “like a sauna you can’t walk out of”, while another described their home as “stifling, suffocating … unliveable”. Two people went to the accident and emergency department at their local hospital because of the impact the heat was having on their health. 

In early August Lee, a 38-year-old who lives with a long-term health condition that affects his immune system, told the Bureau that the impact of the heat on his ability to rest left him feeling so run down that he contracted a chest infection that lasted longer than a fortnight. 

[The heat] makes it worse. It makes it impossible just to cool down or be comfortable enough to sleep. The heat aggravates my cough when I have a chest infection. So it’s just like a bit of a double whammy.

Lee South London resident

In the week Lee got sick, two-thirds of participants said the heat at home was affecting their physical or mental health. 

Sleep disruption was an issue for nearly all participants in the study, even on cooler days. Research shows that lack of sleep can affect people’s mood, their memory, increase stress and exacerbate mental health issues. 

While some people had access to air-conditioned spaces such as their workplace or their local library, more than a quarter told the Bureau they had nowhere to go to keep cool when it’s hot. “It’s horrible, I want to escape but I can’t” said one study participant.

“Unless we prepare our homes for ongoing and future climate change, excess heat exposure will have a range of negative impacts on human comfort, productivity, wellbeing and health, with the most vulnerable in society disproportionately affected” said Professor Mavrogianni.

To find out more about how we’re acting on breaking the link between climate change, housing and health, get in touch with us.