The UK is heading into a heatwave and sleeping in hot weather can be uncomfortable – here's what seven health experts say about leaving your fan on overnight22:32, 24 May 2026The UK is preparing to bask in a heatwave this week – and the Bank Holiday could become the hottest day of the year. Temperatures could soar to 30C in the coming days.‌And with the city and much of the nation bracing for an extended spell of warm weather, one of those timeless questions is certain to resurface – should you leave your fan running overnight?‌To find out, I consulted six health experts about whether it was preferable to have the fan on or off, and they all reached broadly the same conclusion, reports the Liverpool Echo‌What the experts saidThe general agreement among the experts was that it was acceptable to have a fan running as this would make your sleeping environment more comfortable. Dr Luke Powles, Clinical Director at Bupa Health Clinics said: "If you find sleeping with the fan on all night provides you with relief from the heat, it's fine to continue doing so."Others may find that, if left on for too long, a fan can dry out their skin or nose, or aggravate allergies. For those affected, try to avoid the fan aiming directly at your body, use it on oscillate mode, or only have it on for shorter periods to see if it helps.".Meanwhile, Chris Tattersall, the managing director of Woolroom, a company specialising in "sleep-enhancing bedding, mattresses and home accessories" said it depends on what type of fan someone had, either desk or ceiling.‌Chris said: "Yes, keeping the fan on overnight will help to maintain a steady airflow through your bedroom, which is crucial for sleep in a heatwave."For those with a ceiling fan, try adjusting it to run counter-clockwise at a high speed to keep the air moving while you sleep. Ultimately when temperatures rise and sleep gets harder, I would advise using any technique possible to help maintain a comfortable sleep environment and the ideal bedroom temperature of 18 degrees."‌Superdrug's Pharmacy Director Craig Watt also backed the idea of keeping the fan running, but cautioned that there could be an unpleasant side effect if it remained on throughout the night.He said: "Keeping a fan on overnight can help make sleeping in a heatwave more comfortable, particularly if your bedroom feels stuffy or overheated. However, constant airflow can sometimes dry out your nose, throat or eyes, especially for people who already suffer from allergies or congestion. Staying hydrated is important, and using products such as a saline spray can help relieve dryness or irritation caused by circulating air overnight."Speaking in association with Bensons, The Sleep Geek James Wilson also lent his support to the notion of a cooling fan in the bedroom. He said: "If the noise doesn't bother you, and provided its not too close, leaving a fan on overnight can help you feel cooler and more comfortable in the heat, even if it's circulating warm air."‌Dr Deborah Lee, of the Dr Fox Online Pharmacy, stressed that keeping the fan running offered a dual advantage, both reducing the room's temperature and boosting any incoming breeze.She said: "It's good to keep the fan on overnight for two reasons. It causes a wind-chill factor which helps cool you down, plus the breeze speeds up the evaporation of sweat which lowers body temperature. It's also very helpful to place a bowl of ice in front of the fan which causes a cold spray into the room."‌Duux's cooling expert Matt Ladell adopted a more measured stance, suggesting it was preferable to simply use the fan to bring the room temperature down rather than leaving it running throughout the night.He said: "Keeping a fan on overnight can be helpful during hot, restless nights, but in most cases it is better to use it to help cool the room and get you to sleep, rather than having strong airflow blowing directly at you until morning."Rather than directing the fan straight at your face or body all night, position it at the foot of the bed, near an open window when the outside air is cooler, or across the room so it circulates air more gently and evenly. This helps reduce the dryness or discomfort that some people experience when a fan is blowing directly onto them for long periods."‌Meanwhile, Dr Punam Krishan, an NHS GP, in association with Stannah added: "A fan doesn't actually lower the temperature of a room. It works by moving air across your skin, helping sweat evaporate more efficiently and allowing your body to lose heat. During warm weather this can improve comfort and help some people feel cooler overnight although, in very extreme heat, a fan on its own may be less effective and additional cooling measures may be needed."NHS guidance and warningsWhile using a fan overnight is broadly considered safe, there are several important considerations to bear in mind. The NHS highlights that fans can contribute to excessive dehydration, advising that they should be positioned at a suitable distance from individuals, not directed straight at the body, and that people should drink regularly.It also comes down to the individual. Those who suffer from allergies should exercise caution, as a fan can circulate pollen and dust throughout your bedroom.Article continues belowProlonged airflow directed across your body can equally cause your skin to dry out.