Fans vs portable air conditioners: how much do they cost to run?
How much does it cost to run fans and portable ACs? I did the maths so you don’t have to
Unless you’ve been living under a (cool and shady) rock, chances are you heard about the insanely hot heatwave that the UK experienced last week. It got up to 37° in some places in the UK, so unsurprisingly, fans and portable air conditioners saw a huge increase in sales and usage – but what does this mean for your bills?
My husband and I both had to work from home all last week, as the train services discouraged us from travelling unless absolutely necessary. While I used a handheld, cordless fan to cool me down, he preferred a desk fan and we both used two full-sized fans overnight, so we’ll definitely be seeing an increased energy bill for June.
But I decided to run the numbers to see if using a fan or portable air conditioner for several hours actually makes a difference to your energy consumption and costs – here’s what I found.
P.S. For general guidance on air cooling units, check out our comparison guide on fans vs air conditioners to find out which option is best for you.
How to calculate the costs
Before I go into the costs of each fan type, there’s a simple way for you to work out your fan and air conditioner costs yourself. Don’t worry, if a math-challenged person like me can do it, so can you!
First, find the kilowatts (kW) usage of your fan. This will be listed on the website you bought it from and the packaging it came in. It might be shown in watts so simply divide that number by 1,000. From there, multiply the kilowatts by the number of hours you plan to use your fan or AC unit for.
Finally, multiply this by electricity rate. As of July 2026, the Ofgem Energy Price Cap electricity rate is 26.11p per kWh. For calculating fan costs, this will be 0.2611.
How much does it cost to run a fan?
For starters, the most popular fan types – tower, pedestal and desk – all have similar wattages and cost the same amount to run per hour. In general, tower, pedestal and desk fans cost 1p to 2p to run per hour. These types of fans vary from 25 watts to 80 watts, with most households operating between 40 and 60 watts.
To give you a couple of examples, let’s say you have a 25 watt desk fan that you want to use for six hours. By calculating 0.025 x 6 x 0.2611, the total is 0.039 which rounds up to an average of 4p.
On the other end of the watt spectrum, let’s take an 80 watt tower fan that you’re using for 10 hours. The total for 0.08 x 10 x 0.2611 is 0.20 which means you’d be paying 20p for usage.
How much does it cost to run a portable air conditioner?
Compared to a fan, a portable air conditioner costs a lot more as it uses more wattage. The average portable AC unit uses between 700 to 1,500 watts per hour as they’re actively cooling the air around you and expelling it around the room, as opposed to fans which carry hot air away from you which gives a cooling effect.
Portable air conditioners are often measured in British Thermal Units (BTU). smaller air conditioners will have a lower BTU while large air conditioners will have a higher BTU and therefore use more electricity. In terms of conversion, if you have a 700W air conditioner, this equates to 5,000 BTU.
The maths is exactly the same as when we worked out fan costs. So, if you have a 900W air conditioner that you want to use for eight hours, you’ll calculate 0.9 x 8 x 0.2611 which totals £1.88.
