Bristol is set for the hottest week of the year so far - with temperatures peaking at 30C.
During the three-day heatwave, the mercury will not dip below 17C overnight, which means scores of people might rush to buy a fan to help them sleep.
While it might be tempting to leave one switched on to cool the room, experts warn it could be bad for your health.
According to website Sleep Advisor, as fans circulate the air, they can move around dust particles and other potential allergens which can cause irritation.
It says: "As a fan moves air around the room, it causes flurries of dust and pollen to make their way into your sinuses. If you’re prone to allergies, asthma, and hay fever, this could stir up a whole lot of trouble.
"Also, take a close look at your fan. If it’s been collecting dust on the blades, those particles are flying through the air every time you turn it on."
What are the other ways to keep cool at night?
- Splash your sheets - Giving your bedding a light misting of water can make cool the room.
- Turn off all the plug sockets - Electrical sockets kick out a surprising amount of heat.
- Don't drink booze before bed - make sure you keep a cool glass of water by your bedside to stop you from overheating.
- Rinse your wrists - Washing either your wrists or your feet with cold water before you hit the hay can help you to cool down
