Temperatures are soaring again as the latest heatwave sweeps through the UK.
And while it's great news for those making the most of summer, the balmy weather could spell bad news for our electricity bills.
Auto energy switching service Migrate reckons almost half the population use electric fans to help them stay cool during the hot, summer nights.
Their figures suggest, overall, that means electric fans add £1.7million a day to UK energy bills.
But on an individual level things are far more reasonable - with the typical electric fan costing just 7p to run for 8 hours.
This is worked out based on the output of a typical fan (70W) with the average unit cost for electricity being around 18p.
Of course, if you don't want to use a fan - or discover you can't get one - there are other ways to stay cool.
Other methods of avoiding restless nights include opening a bedroom window, sleeping without bedcovers, sleeping in separate beds, freezing or filling a hot water bottle with ice water, and switching to a lower tog rated duvet.
How to keep cool at night
Take a cold shower before bed
Keep bedroom blinds and curtains closed during the day to block out the sun
Use a spray bottle filled with cold water for a cooling mist on demand
Create a DIY air conditioner by putting a bowl of ice in front of a fan
Chill a pair of socks in the fridge and putting them on before bed
Max Green, energy expert at Confused.com which conducted the research for the Mirror, said; "News of a heatwave is an omen of sleepless nights to come.
"This year the discomfort isn't limited to the night; many homeworkers won't be able to benefit from the perfectly adjusted air conditioning systems of their employer's offices.
"The stifling heat can confuse our judgement when it comes to deciding whether to fork out for an expensive cooling system.
"They can be costly to buy and run, and are only useful for the few hot days the UK experiences every year.
"The humble electric fan is still one of the most common solutions for combating the heat, and at a cost of roughly 7p a night, it comes at a price that the majority of people will be willing to pay for comfort."
If you are worried about how costs could add up over the course of the heatwave, read our guide on how to make sure you're on the best possible energy deal.