Independent comparisons. We may earn from shop links. More info

Evaporative cooler vs air conditioner

Updated: 21 October 2026

One box is a fan with a water tank. The other is a portable air conditioner with a hose. The decision is about heat and moisture. A water fan adds vapour and has nowhere to send heat. A refrigerant unit rejects heat outside and costs more to run. This page does not rank the water fans against each other. That table is the [fan with water cooling comparison](/hub/cooling/fan-with-water-cooling). Peter F. used public UK sources and these listings, not a side-by-side lab test, on 20 October 2026. Our amazon.co.uk links can earn a commission at no extra cost to you.

One box is a fan with a water tank. The other is a portable air conditioner with a hose. The decision is about heat and moisture. A water fan adds vapour and has nowhere to send heat.

Our top picks

HandFan HandFan handheld misting fan

Best overall

HandFan HandFan handheld misting fan
6.8/10about £18.99
View offer
KOMORE KOMORE tower cooler and heater

Rank 2

KOMORE KOMORE tower cooler and heater
7.8/10about £135.99
View offer
BLACK+DECKER BLACK+DECKER 6 L smart cooler

Rank 3

BLACK+DECKER BLACK+DECKER 6 L smart cooler
5.5/10about £87.29
View offer
On this page
  1. 1.What each machine does to the air
  2. 2.Windows, hoses and wattage
  3. 3.When a water fan is enough
  4. 4.What not to believe on the title

What each machine does to the air

An evaporative cooler wets a pad or throws a mist. The stream can feel cooler, and the water stays in the home as vapour. Energy Saving Trust says these units cool air near the machine and add moisture. None of these listings shows a refrigerant circuit or an exhaust hose. A title that says air conditioner, on a page with a 6 L tank, is still a water fan. A portable air conditioner sends heat outside through a hose and tends to dry the air. A dry fan does not lower room temperature and does not add litres of vapour. If the flat is already damp, that matters more than a water-tank logo. The NHS says electric fans can help below 35°C. That is about moving air, not a treatment for heatstroke.

Windows, hoses and wattage

Evaporation needs an air path. Honeywell’s guide says not to run a portable evaporative cooler in a closed room. A portable air conditioner wants the hose fitted and the room closed. Copy the hose routine onto a KOMORE or a BLACK+DECKER and you trap moisture. How to run the water fan is the how to use page. USB personals here are about 4 W to 8 W. The KOMORE and the BLACK+DECKER state 65 W in cool mode and the Air Pro 80 W. The serebrant 2000 W line is the heater, so leave it out of this bill. The Guardian, on 13 August 2025, described portable air conditioners around 1,000 W and other evaporative units, not these ASINs, at about 26–87 W. Energy Saving Trust illustrates about £0.14 to £0.30 for 24 hours of a fan, about £0.27 to £0.39 for an evaporative cooler, and about £4.62 to £5 for portable air conditioning. That is an illustration, not your tariff.
HandFan HandFan handheld misting fan

Testsieger

HandFan HandFan handheld misting fan
6.8/10about £18.99
View offer

When a water fan is enough

Choose the water fan when you will sit in a ventilated breeze, the room is not already clammy, and you want the lower running cost. The HandFan is enough when only you need to feel cooler. A 65 W or 80 W tower reaches more of a small room, and reviewers often call it slightly cooler than a fan. A muggy shut room is the poor case. Choose a refrigerant portable unit when you need the room colder and drier, with heat sent outside. Choose a dry fan when the home already has condensation or mould. Do not buy a water fan because the title says it dehumidifies. If you still want a tank, the buying guide orders the litres, the watts and the plug. None of these ASINs was tested here against a named air conditioner.

What not to believe on the title

“Air conditioner” and “mini air con” appear on water-tank listings here. The check is the tank, the missing hose, and a cool-mode wattage around 65 W to 80 W where one is printed. A 4 W mister is further from a portable unit. These fans humidify. Ignore a slogan that promises a large Fahrenheit drop or a comfortable room in three seconds, and ignore a 2000 W figure when you are comparing cooling draw. Ice packs chill the first minutes. They do not dump heat outdoors. Price and stars inside the water-fan table do not change that fork.

Common questions

Do air coolers work in a UK summer?
They can, as a cooler stream, when the air is not already very humid and you leave a path for ventilation. Honeywell describes useful evaporative cooling around 60% relative humidity or below. They work poorly as a substitute for air conditioning in a shut, muggy room, which is a common British evening. Energy Saving Trust’s point is the same: you feel cooler air near the unit, and you add moisture.
What does a portable air conditioner do that a water fan cannot?
It removes heat from the room and sends that heat outside through a hose, and it tends to dry the air rather than wet it. A water fan has no hose and no refrigerant circuit in these listings. It can make the breeze feel cooler. It cannot park the heat outdoors. That is why the window setups are opposites.
Which one costs less to run?
The water fan, on the published illustrations. Energy Saving Trust puts an evaporative cooler at about £0.27 to £0.39 per 24 hours and portable air conditioning at about £4.62 to £5, with a dry fan even a little lower than the cooler. Towers in this set state about 65 W to 80 W. A portable unit is often discussed near 1,000 W. Those are scales, not your meter reading.
Do you open the window for both?
No. Open a path for the water fan so moist air can leave. Fit the hose and keep the room closed for a portable air conditioner so the cooled air stays in. Using one routine on the other machine is the usual reason the first evening feels like a failure. You still need not open every window for the water fan. One air path is the aim.
Will a water fan dry the room?
No. It adds moisture. That is the trade for the cooler stream. If you already have condensation or mould, it is the wrong machine. A refrigerant air conditioner is the one that can dry while it cools. A dry fan does neither drying nor wetting; it only moves air.

Related pages

Fan with water cooling for a bedroom

Fan with water cooling

Best fan with water cooling UK: tower or face mist

Evaporative air cooler buying guide: UK tank and watts

How to use an evaporative air cooler: fill and vent

Sources

Public UK sources from the research digest, used for this page on 20 October 2026. Prices, stars and review counts are the amazon.co.uk figures in this comparison. Listing slogans about a temperature drop were not treated as measurements.

  1. Energy Saving Trust: tips to keep your home cool (retrieved 20 October 2026)
  2. NHS: heatwave, how to cope in hot weather (retrieved 20 October 2026)
  3. GOV.UK: beat the heat, keep cool at home (retrieved 20 October 2026)
  4. Electrical Equipment (Safety) Regulations 2016, Great Britain (retrieved 20 October 2026)
  5. Electrical Equipment (Safety) Regulations 2016, regulation 35 (retrieved 20 October 2026)
  6. HSE: other legionella risk systems (retrieved 20 October 2026)
  7. Honeywell: portable evaporative air cooler guide (retrieved 20 October 2026)
  8. The Guardian, 13 August 2025: evaporative air coolers (retrieved 20 October 2026)