One in every six babies in England are living in overheated homes, causing sleep disruption and serious health risks, according to new analysis.

The National Housing Federation (NHF) and the Chartered Institute of Housing (CIH) found that more than 70,000 babies are living in overly hot homes as climate change drives record temperatures across the country.

A rare red warning for extreme heat was issued for parts of England and Wales this week, with hundreds of schools closing their doors as temperatures were expected to hit record levels.

In total, an estimated 1.6 million children are living in overheated properties, according to analysis of English Housing survey data.

This carries serious health risks for children under five, especially babies, who are less able to regulate their temperature and manage dehydration.

It increases the risk of sudden infant death syndrome (SIDS) in newborns, with parents advised to keep rooms between 16C to 20C, something which can be impossible to do during heatwaves.

Jackson Bylett lives in a new-build flat in Newham with his five-month-old daughter, and said he and his wife were anxious about the impact of heat on her wellbeing – the baby’s room has reached over 30C.

“Everything you read about safe sleeping for newborns says you want to keep the room between 16C and 20C, and the thermostat on the wall is slowly creeping up as the day goes on and there’s nothing you can do,” he said. “It’s getting up to 30C-35C, and the risk we’re talking about here is your child dying.”

He said parents in the UK are not given enough advice about what to do to keep babies cool during a heatwave, despite it being a common event.

“My wife and I had so many conversations about becoming new parents but not once did we think about raising a child in these extreme temperatures and what that would mean,” he said.

James Grant, who lives in a 1930s house in east London and has a one-year-old son, said he had boarded up the windows in his son’s nursery to keep the heat out during the hottest part of the day.

“Every time I wake up in the night, my first thought is to look at the temperature on the baby monitor. It has got over 30C in there at night,” he said. “In the morning when it’s cooler, we open up all the windows to get some air through but I only got it down to about 25C this morning.”

He said the heat had disrupted the baby’s sleep and exacerbated issues with dehydration. “Over the next couple of days as it gets hotter, I don’t know what we’re going to do,” he said.

Most of England’s homes are built to retain heat, and lack cooling features common in warmer countries, such as shutters or air-conditioning.

A poll by YouGov found that nearly three-quarters (71%) of parents experiencing overheating in their home said it disrupts their children’s sleep, affecting an estimated 1.1 million children.

Nearly a third (31%) said it is harming their children’s physical health, and 49% said it affects their children’s ability to concentrate. Kate Henderson, chief executive of the NHF, said: “It’s now clear that increasingly extreme heatwaves are making it impossible for parents to make their homes completely safe and comfortable.

“As heatwaves become more frequent and more intense, we need urgent action to ensure homes can be kept at safe temperatures and are fit for the future.”

The Met Office said the likelihood of 40C temperatures has tripled since 2000, and future heatwaves could last a month or more. By 2050, more than nine in 10 homes in the UK are projected to overheat, with heat-related deaths potentially rising to 10,000 per year without adaptations.

The NHF said housing associations and local authorities were using shading and ventilation to retrofit homes, and even opening free cool spaces for residents. But more support is needed to do this at scale.

Gavin Smart, chief executive of the CIH, said the statistics were a “worrying reality” and children’s education would suffer if they’re sleeping in bedrooms that are too hot.

He said the government needed to think carefully about whether the 1.5m homes it is committed to building this parliament will be able to cope with hotter temperatures.

“We need to strengthen building regulations around overheating and start to consider policies that will support people with the energy costs of keeping cool during future heatwaves,” he said.

How to keep babies safe during a heatwave

Keep room temperature as cool as possible
The main advice is to keep your baby’s room between 16C and 20C for sleeping. The Lullaby Trust, a charity which aims to prevent unexpected baby deaths, suggests using a fan to cool the room, but do not aim it directly at the baby. Putting a bowl of ice in front of a fan can help cool the air as it moves. The charity also suggests keeping curtains closed during the daytime to keep out light and heat, and buying a room thermometer.

Use light clothing and bedding
To keep babies as cool as possible use light bedding and clothing – a short-sleeve vest or just a nappy is fine. The baby charity Tommy’s suggests using cotton sheets and blankets, and avoiding waterproof sheets which can be sweaty. They also advise against swaddling the baby, so they can kick off the blanket more easily if they get hot.

Keep the air flowing when outside
Do not cover a buggy or pram with a blanket to keep off the sun, as this can stop the air flowing and make it hotter for the baby – and it also means you cannot easily see if they are getting too hot. Instead, use a clip-on sunshade or parasol. Use factor 50 or higher sun cream on babies six months and older –younger babies should wear a hat and be kept in the shade.