As the Met Office issues extreme heat warnings, we look at how to keep cool – and the best models

Temperatures are set to soar this weekend but will running an electric fan to keep cool also send your bills through the roof?

This week the Met Office issued an amber extreme heat warning for much of England and Wales for Sunday, Monday and Tuesday. There was also a red warning for parts of England, where temperatures could reach 40C.

Many people will have had fans running all this week – perhaps to provide a blast of cool air while they are working from home, or next to their bed at night.

Many others will be planning to buy one: sales of electric fans have increased by up to 1,630% this week, says the online marketplace OnBuy. However, energy bills have soared during the cost of living crisis, and running a fan will add to your expenses.

Guardian Money decided to find out how much it would cost to run different types – although the actual figure will vary depending on the fan and how much you pay for electricity.

The estimates are based on the electricity supplier’s standard variable tariff, which is protected by the energy price cap.

According to numbers crunched by Uswitch, it costs 1p to run a standard desktop fan for an hour – in other words, 8p for an eight-hour working day.

If you decide to have it on all day and night, it would cost 24p over 24 hours, so seven days of that would add £1.68 to your bill. Pedestal fans cost more, at a little under 2p an hour, which would add up to 14p for an eight-hour working day.

Running a pedestal fan for 24 hours straight would cost 41p a day; that’s £2.88 after seven days.

Portable air-conditioning units are more expensive to buy and more costly to run at 28p an hour.

A built-in air-conditioning unit comes with the biggest price tag of all : according to the Uswitch research, it will cost 75p an hour.

Air conditioning is, of course, bad news for the planet: it accounts for about a fifth of the electricity used around the world. Much of that comes from power stations that emit greenhouse gases.

Will Owen, an energy expert at Uswitch.com, says: “We’ve all got used to the fact that staying warm is more expensive than ever but the same is true of keeping cool as we enter the first heatwave of the year.”

He adds that while many people working from home won’t have a perfectly chilled air-conditioned office, there are things they can do to keep their home cool.

“While air-conditioning units are an effective way to keep a room cool, they consume a lot of power and could bring about a nasty surprise when the next energy bill arrives.

“With high energy prices, it’s important to keep energy bills down even in the summer months.”

In the UK, a health alert has been issued, instructing people to look out for older people, young children and babies, and those with underlying health conditions, who may struggle in the heat.

Britons have been advised to close curtains in rooms that face the sun to keep temperatures down, and to remember that it may actually be cooler outside.

The Met Office recommends drinking plenty of water, not consuming too much alcohol, and dressing appropriately for the weather.

We have rounded up a few of the best-rated fans on sale.

It is worth comparing prices before you invest in a fan to make sure you are getting the best value for money, and also checking the energy usage, so you have an idea of how much it might add to your electricity bill.

There are a range of Oypla electric fans available on Amazon, including a desktop model (£12.99) that can also clip on to surfaces such as shelves.

Igenix also offers a sizeable range, many of which receive good reviews.

The Honeywell Comfort Control tower fan was £55-£60 from Amazon this week. It has three speed settings, a timer function and can be remotely controlled.

Meanwhile, the handheld HandFan (about £22) scores 4.5 out of five on Amazon. It has three speed modes, is foldable, which means you can stand it on a desk, and can be charged via a USB plug. It boasts a “misting function … to keep the air hydrated while cooling you down”, with a 55ml water tank it claims lasts for up to 40 minutes.