Fans: tower, desktop, pedestal and bladeless
Typical cost for 24 hours of continuous use: £0.20 – £0.40
- Using a fan can be an inexpensive way to keep cool in hot weather. Rather than cooling the air directly, fans create air movement which helps sweat to evaporate, meaning you stay cool.
- More expensive tower, desktop and pedestal fans aren’t necessarily more efficient or cheaper to run than cheaper models. Bladeless fans, which are often the most expensive to buy, have similar running costs to other models. The type of fan you choose therefore largely depends on personal preference.
- Due to their low energy use, fan have minimal carbon emissions. For example, using one fan for an average of eight hours a day throughout the summer would generate around 10kg of carbon dioxide emissions (roughly equivalent to driving from York to Leeds), or less depending on the model.
Top tip: using a small USB fan on your desk can be a cheap way to stay cool while working at a computer, with running costs as low as £0.01 per day.
Portable air conditioning units
Typical cost for 24 hours of continuous use: £6.00
- Like fans, air-con units create air flow, but they also remove heat from the air to lower the temperature of a room.
- Portable air conditioning units are significantly more expensive to buy than most fans and use much more energy. Running a portable air conditioning unit continuously for 24 hours would cost more than 20 times as much as running a typical freestanding fan for the same amount of time.
- Fitted air conditioning units aren’t commonly found in UK homes.
- Because air-con units use more energy than other cooling devices, running one also results in more carbon emissions. Using a portable air-con unit for an average of eight hours a day during the summer would result in a total of around 140kg of carbon dioxide emissions, the same as a seat on a flight from Belfast to Paris.
- If you do need to use air conditioning, make sure you get the right size unit for the room you’ll be cooling and check that there are no gaps where the exhaust pipe goes out of the window, as this would let warm air back into the room.
Top tip: keep internal doors closed when an air con unit is running to stop warm air entering from other parts of the house. When you turn the unit off, unplug it at the wall to prevent any energy potentially being used in standby mode.
Evaporative air coolers
Typical cost for 24 hours of continuous use: £0.40
- Like air conditioning units, evaporative air coolers remove heat from the air to lower its temperature. Instead of using a refrigerant chemical like in an air conditioner, evaporative air coolers use a fan to draw air over water. When water evaporates, it cools the air in the space near the unit.
- A small, portable evaporative air cooler is likely to have a similar or slightly higher running cost compared to a typical fan but are generally more expensive to buy.
- Compared to portable air-con units, evaporative air coolers use less energy. Using one for an average of eight hours a day during the summer would result in similar carbon emissions to using a fan – around 10kg of carbon dioxide, roughly the same as driving from York to Leeds.
- As they are evaporating water, these units can increase the amount of moisture in the air in your home so make sure to keep rooms well ventilated.
Top tip: keep internal doors closed while using an evaporative cooler to prevent warm air from entering the room and unplug when not in use.