Around 20% of homes in England overheat every summer. (Image: Pixabay)
In the summer of 2015, mature student Mary Chase moved into a ground floor studio in Bath and immediately noticed a curious design feature.
The flat was fitted with the kind of slide windows you might expect to find in a fast food drive-through, only when you pulled them across, they didn’t open into the fresh air, but onto a set of stained glass panels. The studio had been converted from a pub, and the builders had apparently neglected to add any opening windows.
“I emailed [my letting agent] immediately and told them that it was unbearably hot, so much so that I felt physically unwell,” says Chase, who asked the Big Issue not to use her real name.
Chase has an invisible disability, and found herself suffering constantly in the stuffy heat of the flat, even on cooler days in the summer. A casual smoker at the time, she upped her cigarette intake just to get outside, and was forced to do laps around the block to escape the oppressive temperatures.
Chase eventually moved out of her flat in 2016. Since then, Britain has baked under a series of record-breaking heatwaves, including a 2019 summer which marked one of the hottest ever recorded in Britain. By 2050, summers like this are expected to be the norm.
As a nation starved of sunshine for the majority of the year, the UK remains a place where the public are unused to long periods of heat. Yet it’s not just people who are ill-adapted to high temperatures: almost all our housing is too.
Without fast adaptation, it’s vulnerable people — from the elderly to the low-income and disabled — who’ll be left most exposed.
‘The effects of heat are underestimated’
The UK has a reputation as a cold, wet country for good reason: aside from being depressing, the UK’s weather is cold enough that thousands die every year in draughty, poorly-insulated homes. In 2020, an estimated 8,500 people died this way in England and Wales alone.
That year, the record for heat deaths was at 2,500.
Yet according to projections from the government’s climate advisers, the Climate Change Committee (CCC), heat deaths could reach 7,000 a year by 2050 – when 80 per cent of the UK’s housing stock will still be in use.
It’s a threat few, including policymakers, have paid attention to, says Bob Ward, policy and communications director at the Grantham Research Institute on Climate Change.
“The effects of heat are underestimated in the UK, but we have literally hundreds of people in this country who die every summer because of overheating,” he says.
“Mainly this is people who already have underlying health conditions, and often they’ll die alone – heat kills you much more quickly than cold.”
Beyond deaths, overheating can have far-reaching impacts on mental and physical health, as Chase herself discovered.
“[The heat] made my anxiety really bad. And to this day, I still struggle with regulating my body temperature when it’s really hot or cold,” she says.
“A year after moving out of the flat I was at my graduation and it was a really hot day – I very nearly passed out, but everyone else was fine.”
‘We’re still waiting to see a plan’
It’s not as though nobody has been banging the drum about this ticking time-bomb.
After a decade of ignored warnings, the government eventually introduced a “Future Homes Standard” in 2021 – a policy which means all homes built from now on will have to be well-ventilated and resilient to high temperatures.
It’s a change welcomed by the likes of Ward, though he maintains scepticism about the ability of local councils to check that developers are complying.
“I think builders are now aware of [the need to minimise overheating]. The question is, whether the enforcement processes are in place.”
The most glaring flaw with the policy, however, isn’t regulation. The Future Homes Standard only covers building new homes – not retrofitting existing ones.
And while Boris Johnson’s recent announcement of fresh funding for home insulation could be a step in the right direction, there is a risk that insulating homes against cold could lock in even more heat.
Done right, old homes can be made warm in winter and cool in summer, explains Mike Davies, professor of building physics and environment at University College London.
“But if, for example, you don’t provide adequate ventilation but have south-facing windows, you could actually exacerbate overheating.”
‘We’re not getting used to the idea that it’s dangerous‘
It’s a scandal that very few are even aware of: over the past decade, hundreds of thousands of brand new homes have been built with no protections against the scorching heat they’ll face in years to come. Research from the CCC suggests, in fact, that all UK new builds are at risk of overheating.
For those who buy these homes, this could mean a hefty retrofit bill at some point in the future. For those who rent these homes, the decision to fit shutters or improve ventilation won’t even be theirs to make.
People like Chase have already experienced the powerlessness of waiting on a landlord to make a living situation bearable.
Much younger at the time, Chase feels her naivety and fear of speaking up was taken advantage of.
“I wasn’t very clued up back then – I realise now I should have gone straight to the council [about the heat] when the letting agent didn’t respond,” Chase recalls.
“It just completely exacerbated my anxiety, and I was struggling with a lot of stuff anyway and it felt like too much to try and manage,” she adds.
Aside from lacking confidence or awareness, there are a whole set of compounding factors that make minority groups and vulnerable people like Chase more likely to live in homes at higher risk of overheating.
Low-income households, ethnic minorities and people with disabilities are, for instance, more likely than the general population to be renting homes, and it’s rented and social housing — often flats — which are more prone to overheating.
“Unlike a free-standing house, flats are surrounded by other homes, making it harder for heat to escape,” says Professor Kevin Lomas at the University of Loughborough, who conducted research into overheating in homes in 2018.
He added that top floor flats, where heat rises to, are worst affected. “Plus, there are fewer outside walls, making ventilation difficult,”
Reduced space in flats, meanwhile, makes escaping heat difficult or even impossible, and there are few safe havens from high temperatures if there are no trees nearby to shelter from the sun.
“I actually think I probably became quite a burden to my friends at the time, because I was constantly asking them to meet me for studying in Starbucks or round at their place,” Chase recalls.
Outside of design, a whole host of other factors exacerbate overheating for vulnerable people and those on the lowest incomes in urban areas. Pollution, crime, noise and overcrowding all put restrictions on opening windows and send temperatures soaring.
Those on lower incomes are less able to afford cooling devices like fans, while also being more likely to do shift work, sleeping during the day when the sun is at its hottest.
Advice issued by the NHS on coping in heatwaves suggests “mov[ing] into a cooler room for sleeping” but, for millions, this cool room simply doesn’t exist.
For Chase, the only “safe haven” in her former flat wasn’t in it at all. After meeting her partner, she spent most of her time staying at his place to avoid the heat at home.
“It got to the point where he sometimes would insist I didn’t go back to my flat when the weather was really extreme because he knew just how much it was affecting my health,” she says.
It’s easy to forget, says climate expert Ward, just how dangerous heat can be for people’s health – especially when it comes to the bedridden, elderly and disabled.
“We’re not getting used to the idea that [heat] is actually increasingly dangerous, particularly for those who are vulnerable to the impacts.”
‘You can’t make it affordable by making it unlivable‘
The flat Chase formerly lived in was what developers refer to as a “PDR conversion”: a formerly commercial building adapted into flats through permitted development rights, which do not require full planning permission to go ahead.
They’ve been touted as a nifty solution to the housing crisis, but government-commissioned research from University College London (UCL) in 2020 found that the resulting flats were consistently lower quality , with less space, light and access to amenities. One flat they looked at had no windows at all.
Though not in all cases, these qualities make these types of converted flats particularly prone to overheating. Insurers Zurich UK warned in 2021 that office-to-residential conversions present a “potentially deadly” risk to those living in them during heatwaves. Between 2016 and 2021, 60,000 of them were built in Britain.
“Some standards, like ventilation, are difficult to apply, [to these flats] and that’s particularly concerning in our changing climate,” says Dr Ben Clifford, a researcher who worked on UCL’s PDR project.
For those living in these units, life in warmer weather is already becoming unbearable.
In Enfield, where several conversions have hit headlines for their poor quality, a council survey carried out in 2019 revealed an array of complaints around overheating, overcrowding, noise and poor quality homes.
“I live in a studio with my 5-year-old daughter, and I have to share the bed with her. It’s extremely hot in the spring and summer because of a lack of space,” one respondent wrote.
They might be a fast way to build cheaper homes, says Ward, of the Grantham Institute, but in the rush to do so there’s a risk we’re locking in problems further down the line.
“There’s quite rightly been an emphasis on the need for affordable housing,” he says, “but if you make it affordable by making it unlivable, then that’s not a reasonable trade-off.”
‘People are still looking back at the climate we used to have‘
There are alternatives, though. Roughly 190 miles from the former office blocks in Enfield, a row of nine brightly-coloured homes washed hues of blue and red stand on Thornpark Rise in Exeter as testament to the fact that building climate-resilient homes is no impossible feat.
These nine homes, built as social housing by Exeter Council themselves, used what’s known as the “Passivhaus Standard”, regarded as the most effective method for ensuring that homes emit little carbon dioxide, while staying warm in the winter and cool in the summer.
Homes can also be retrofitted to make the grade and, already, some councils have caught on with projects of their own. Herefordshire County Council has become the UK’s first to commit to Passivhaus standards in all new council housing.
These methods, as a spokesperson for the Passivhaus Trust concedes, are more expensive than standard building methods. But the final product is money-saving in the long term, they said.
Research from the Building Research Establishment in 2021 estimated that substandard housing is currently costing the NHS £1.4bn annually. As more homes heat up, the costs could spiral even further.
Adopting the standard might seem like a no-brainer, but progress on the overheating and insulation issue has moved at a glacial pace in the policymaking and construction worlds. This is largely, says Ward, down to a lack of awareness.
“[A lot of people] are still looking back at the climate we used to have, not the climate we’re going to have in the future.
“We need to understand that when we’re building a house in London today it’s going to be exposed to hotter, longer and more intense periods of heat.”
For thousands of people, unbearable temperatures in Britain are no distant prospect, but a reality getting worse as every summer passes. Perhaps because it’s society’s most vulnerable being affected, their plight remains largely unnoticed.
“This is already a scandal. We have hundreds of people dying every year,” says Ward.
“And if this problem keeps growing because we’re incapable of building properly to protect people from the heat, then this really would become a massive national scandal.”