Evaporative air coolers offer a more energy-efficient alternative to air conditioning, using a fraction of the electricity to lower room temperature by a couple of degrees. In tests of nine models, the Swan Nordic air cooler emerged as the top performer, cooling a room by 1°C in an hour while consuming only 26W—compared to a typical portable air conditioner's 1,000W.
How Evaporative Coolers Work
These devices pull warm air through water-soaked pads. The water evaporates, using energy and cooling the air. Unlike air conditioning, they don't produce fridge-cold air but create a refreshing sea-breeze effect. They also humidify the air, so they are unsuitable for damp or mould-prone environments. Most can be used as standalone fans without the evaporative function.
Energy and Cost Efficiency
At the July 2026 price cap of 26.11p per kWh, a 1,000W air conditioner costs about 26p per hour to run. In contrast, the Swan Nordic uses 26W, meaning it can run for 38 hours on the same electricity. The Morphy Richards Flexi Freeze, a rechargeable personal cooler, charges at 10W and runs for up to 15 hours. The Shark FlexBreeze Pro Mist uses 21W on its top setting when charging simultaneously.
Test Methodology
Caramel Quin, an award-winning consumer tech journalist with a mechanical engineering degree, tested nine evaporative coolers from different brands. She used a power meter to measure electricity usage, a digital thermometer from one metre away to gauge temperature change, and the Sound Meter app for noise levels. She also assessed subjective factors like cooling sensation, noise annoyance, ease of use, design, storage size, and price. Uncollected test units were donated to Furnishing Futures, a charity supporting survivors of domestic abuse.
Best Overall: Swan Nordic Air Cooler
Price: £79.99 (currently out of stock)
Dimensions: 29 x 24 x 71cm (WDH)
Water tank: 5 litres
Speeds: 24
Remote control: Yes
Peak noise: 40dB
Power use: 26W
The Swan Nordic combines attractive design with effective cooling. It features a rear drawer for water, two included ice packs, and a rotating front grille instead of oscillation. It offers 24 fan speeds via remote control, produces a powerful breeze, and is quiet enough for sleep. The only downside is the lack of a drain bung; emptying requires tipping the unit.
Best Portable: Morphy Richards Flexi Freeze
Price: £69.99
Dimensions: 18 x 13 x 30cm (WDH)
Water tank: 1 litre
Speeds: 4
Remote control: No
Peak noise: 30dB
Power use: 10W to charge
This rechargeable personal cooler is designed for close use, such as on a desk or in a caravan. It lowered the temperature from 30.6°C to 29.5°C in 15 minutes at 50cm distance. It runs for up to 15 hours on a four-hour charge. However, the noise—a low hum when cooling is on—can be annoying. It does not double as a power bank.
Best for the Garden: Shark FlexBreeze Pro Mist FA300UK
Price: £249.99
Dimensions: 35 x 35 x 93cm (WDH)
Water tank: 5 litres
Speeds: 5
Remote control: Yes
Peak noise: 55dB
Power use: 21W
This cordless fan with misting function is designed for outdoor use. It sprays a fine mist that cools effectively but dampens clothes and surfaces, making it unsuitable indoors. It claims to reduce temperatures by up to 6°C. The fan can be used without the tank indoors, and the pole can be removed for desk use. Run time ranges from 2 to 24 hours depending on speed.
Other Tested Models
The Pro Breeze OmniAir 5l (£119.99) offers aromatherapy via a scent pad drawer and has a side-to-side swing, but failed to measurably cool the room even with ice packs. Its lowest setting is quiet enough for sleep.
Evaporative coolers are most effective in dry environments and should not be expected to drastically alter room temperature like air conditioning. They are best used with doors open for fresh air circulation.
