As UK summer temperatures creep higher, keeping your home and yourself cool is no longer just a comfort issue—it's a safety one. Heatwaves can put lives at risk, especially vulnerable people, and understanding how to manage the heat without breaking the bank or the law has become essential.
At its simplest, staying cool in a heatwave involves a mix of common-sense habits and clever use of everyday items. Opening windows on opposite sides of the house creates a cross-breeze, releasing trapped warm air and drawing in cooler air. But this only works when the outside temperature is lower than inside—typically overnight or early in the morning. During the day, the best approach is to close windows and draw blinds or curtains, especially on sun-facing sides, to keep the heat out. For flats with windows on just one side, opening internal doors and using a fan can help move air around.
“Practical tips for keeping cool in UK heatwaves: home cooling, fan use, product costs, and car idling fines.”
Fans are a cheap and energy-efficient option. Running a freestanding fan for 24 hours costs between 15p and 31p, according to the Energy Saving Trust. Placing a fan in front of an open window (when it's cooler outside) pushes fresh air through the room. You can even put ice cubes in front of the fan to create a makeshift air cooler. But experts warn that using a fan when temperatures climb above 35°C can actually backfire, because it simply blows hot air at you. Air conditioning is more effective but far more expensive: the Energy Saving Trust says 24 hours of continuous use costs between £4.84 and £6.
For UK households, heatwaves are becoming more frequent and intense. The UK's all-time temperature record of 40.3°C was set in Lincolnshire in July 2022, and the Met Office has issued amber warnings for extreme heat. This is why cheap cooling solutions are increasingly sought after. Supermarkets like Lidl now stock affordable options: a 3-in-1 air conditioner that also dehumidifies, costing £149, or a portable fan for £7.99. There are even cooling pillows and dog mats. Reducing indoor heat sources also helps—avoid using ovens, cookers, washing machines or dishwashers during the hottest part of the day.
But there's a trap for drivers. Sitting in a stationary car with the air conditioning running to keep cool can result in a fine for engine idling. The RAC warns that police or civil enforcement officers can issue penalties: typically £40 from a police officer or £80 from a civil enforcement officer, both halved if paid promptly. In some London boroughs, such as Islington, the fine can be £110. The law exists to reduce air pollution, and the risks are real even when temperatures are extreme.
Q: Is it safe to use a fan when the temperature is very high? A: Not always. Professor Mike Tipton of the University of Portsmouth warns that using a fan in temperatures above 35°C may make you feel worse, as it directs hot air towards your body. Below that threshold, fans can help with thermal comfort and lowering body temperature.
Q: What's the cheapest way to cool a room without air conditioning? A: Open windows overnight to let cool air in, then close them and draw blinds or curtains during the day. Use a fan to circulate air—a freestanding fan costs just 15p–31p per 24 hours. Placing a bowl of ice in front of the fan can also help chill the air.
Q: Can I be fined for idling my car in a heatwave? A: Yes. Sitting in a stationary car with the engine running, even with air conditioning on, can lead to a fine of £40–£110, depending on the local authority. The RAC advises against it because of the air pollution caused by idling.
What happens next depends on the weather and government policy. The Met Office continues to issue heat warnings, and temperatures are expected to rise further in coming years. The UK government previously announced plans to increase fines for engine idling, though those changes have not yet been implemented. In the meantime, households can expect more budget-friendly cooling products to appear in shops, and experts will keep refining their advice as heatwaves become the new normal.