‘Do not buy these flats’: residents warn about unbearable heat inside London new-builds | Extreme heat

The sweltering conditions inside Leaside Lock, a new-build development in east London, are hardly a secret. Last June, a warning written in big, capital letters was stuck to the window of one flat. “DO NOT BUY THESE FLATS. TOO HOT,” it read.

It was hard to miss for those walking past the looming high-rises and, after being snapped and posted on social media, the placard has garnered more than 500,000 views. More than a year on, during a summer when the UK recorded its second warmest June and fifth hottest July since 1884, residents say heat is still an issue.

“When I’m trying to fall asleep at night, it gets quite unbearable,” said Lucian Ho, 21, a student who lives near the top of a 28-storey building in the development. Options to cool off in his south-facing flat are limited. “All I can do is open the window,” he said.

The development is situated in Tower Hamlets, which is the most densely populated borough in the UK. Eighty-one per cent of households live in purpose-built flats, the second highest proportion in England and Wales and double the London-wide rate. The borough has also seen a massive sky-rise boom, with 71 buildings with 20 or more floors being built between 2014 and 2024. To top it off, it ranks poorly for green space. All these factors come together to make living in the borough a hot box for many.

Experts have warned that many of the new homes being built in the UK are not designed to withstand the more extreme summer temperatures being seen due to climate change. They have called for the government to update its upcoming future homes standard to include provisions for overheating homes.

The regulations are due to be published this autumn and to come into force from 2027, but the focus has been mainly on how to keep homes warm in winter, rather than to keep them cool in summer.

Up the road from Leaside Lock sits another development, Three Waters. “It feels like you’re in a trap,” said Sandra Monteiro, who lives on the 11th floor in one of the complex’s blocks.

The 41-year-old SEND teacher has lived in the flat with her husband for almost three years but the sweltering heat means she’s considering leaving. “Our temperatures haven’t gone below 27C inside the house in the past two months,” she said. Her thermometer peaked at 33C this summer.

When temperatures inside rise above 25C, risks to health rise too, potentially causing or worsening cardiovascular and respiratory issues, sleep disturbance, mental health problems and heat exhaustion.

Monteiro said the heat in her flat causes frequent headaches. “Exhaustion, feeling like we’re out of breath. We have experienced feeling very fatigued, even when we wake up,” she said. “When we travel abroad we don’t experience as much exhaustion as we do here in the UK, which is definitely to do with the heat.”

The UK Green Building Council has said street trees are a simple and cost effective way to keep homes cool. But Monteiro’s block is situated beside the busy A12 and the streets below are barren of any green space. “If we have the windows open because of the motorway, we get a lot of the dust and the heat that comes from that,” she said.

She bought a 25% share of the home with her husband for £121,000. On top of this, she pays £1,264 per month in rent. “It is my first summer really experiencing these high temperatures and I’m feeling quite unsure about whether I want to continue living here,” she said.

A spokesperson for Peabody, which runs Three Waters, said: “We want residents to feel comfortable in their homes all year round and work with construction partners to ensure homes are designed with ventilation and shading in mind, considering the risk of overheating.”

They said that since new regulations to reduce the risk of new-builds overheating were introduced in 2022, they had added features to new homes like external shutters that let in daylight but block out heat. “We’re also looking at materials that help keep homes cooler during summer and warmer in winter,” it said.

Guiness Homes, which runs Leaside Lock, said that of the 440 properties in their blocks they had only received complaints from four homeowners about heat inside their homes, all of whom were given adaptations to reduce temperatures. “The image you have shared relates to a homeowner who had a specific and unique issue in their property which has been addressed,” they said.

Farther north in the city sits Kestrel House. The looming 55 metre-tall council block became a symbol of inner-city life after being featured on the cover of The Streets’ debut album Original Pirate Material. It lies along a busy thoroughfare in Islington, which – after Tower Hamlets – has the second highest population density in the UK. It also suffers from a lack of green space, and residents have access to an average of 2m² of green space per capita, the lowest amount of any borough in the UK, according the Friends of the Earth.

Chris Brown, 76, has lived at the top of Kestrel House since 1987. In his 38 years living there as a council tenant, he has found heat an increasing problem. In the summer, temperatures inside his 17th floor flat rarely go below 27C. This year, they reached a high of 30C and in previous heatwaves his thermometer has hit a peak of 35C.

The semi-retired psychotherapist fitted an air conditioning unit in his living room due to fears about what the heat could be doing to his health. “I spent as much time as I can in here, in front of the blast of cold air from the air conditioning unit,” he said.

Brown has a heart condition, diabetes and chronic fatigue syndrome. “It does cause people to die, so I became worried,” he said.

Hot homes aren’t just uncomfortable – they can be deadly. During the heatwaves in 2024, UK Health Security Agency figures estimated that about 358 people died at home, in part due to extreme temperatures.

Deaths tend to spike because the heat exacerbates existing medical conditions, rather than directly causing otherwise healthy people to die – overall influenza and pneumonia deaths were 13% higher than they otherwise would have been during the 2024 heatwaves, and circulatory disease deaths, dementia and Alzheimer’s deaths were up 11%.

The heat affects Brown’s current health conditions. “Heat stress makes my fatigue worse so life is just a little bit more of a struggle,” he said. “Sleeping became difficult. It tires me out. I was continually feeling more tired than usual.”

Tall buildings, especially those surrounded by other looming towers, are susceptible to the urban heat island effect – where materials like concrete and asphalt absorb and retain heat. Brown said the heat sticks around, even when temperatures outside reduce. “It doesn’t cool down. It’s like a brick oven,” he said.

Councillor Rowena Champion, executive member for environment, air quality and transport for Islington council said: “We are aware that many people in Islington live in flats built in a different era that weren’t designed for extreme heat. This has a real impact especially for older people, those with health conditions, or families with babies. Tackling overheating in homes must be a shared priority for councils, developers and government. In the meantime, we are looking at practical solutions like reflective coatings and green infrastructure to help reduce overheating in tall buildings.”