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Posted by GoodCooling Team

How Does an Evaporative Air Cooler Work? Evaporative Cooling Explained Simply

An evaporative air cooler looks like a large fan with a water tank. Behind it lies a principle that nature has always used: evaporation draws heat from the surroundings. Here you will learn how this works inside the appliance, what the effect depends on and how to get the best out of it.

The principle: evaporative cooling

Anyone who comes out of the water and stands in the wind feels cold, even though the air temperature stays the same. The water on the skin evaporates and draws heat from the body. An evaporative air cooler uses exactly this effect, only in a controlled way inside the appliance. In physical terms, the lowest temperature that can be reached by evaporation alone is the so-called wet-bulb temperature. It is always below the air temperature, but the gap depends on the humidity.

The three steps inside the appliance

  1. Intake: A fan draws warm room air through the housing.
  2. Evaporation: The air flows through a wet cooling pad. Some of the water evaporates and draws heat from the air.
  3. Discharge: The cooled, slightly more humid air flows into the room.

A small pump keeps the cooling pad moist. There is no more technology to it than that. There is no compressor and no refrigerant, and the appliance needs no exhaust hose. You can find out more about the construction on our technology page.

What the cooling effect depends on

  • Humidity: The drier the air, the more water can evaporate and the more strongly the appliance cools. In very muggy air the effect is small. Details in our article Evaporative air coolers and humidity.
  • Fresh air and exhaust air: To stop moisture building up, the air in the room should be exchanged, for example via an open window or door.
  • Water: The appliance only cools as long as the cooling pad is wet. Cooler water strengthens the effect.
  • Appliance size and air volume: Larger appliances move more air and cover larger areas.

Which appliance for which area?

The manufacturer's specifications for our models give the following cooling areas: the GoodCooling Y5 is designed for smaller rooms of 40 to 60 m², the Y20 and the Y30 for 150 to 250 m². You can find out which model suits your use in the product overview.

Practical tips for operation

  • Position the appliance so that it can draw in and blow out air freely.
  • For indoor rooms, ensure regular air exchange.
  • Change the water regularly and clean the tank and cooling pad so that no germs form. You will find instructions in our article Maintenance and care.
  • For outdoor use, bear in mind the appliance's weather protection.

Frequently asked questions

Does an evaporative air cooler use a lot of water?

That depends on the model. According to the data sheet, the GoodCooling Y5 uses around 3 litres per hour, the Y30 12 to 20 litres per hour.

Does an evaporative air cooler make the air humid?

Yes, because the evaporated water ends up in the room air. That is why ventilation is important, especially in small, enclosed rooms.

Is an evaporative air cooler the same as a humidifier?

No. Both evaporate water, but an evaporative air cooler is designed for the cooling effect and moves a lot of air over a cooling pad.

Conclusion

An evaporative air cooler cools by evaporating water, which draws heat from the air. This is simple and free of refrigerants, but comes with conditions: dry air and air exchange help. How it compares with an air conditioner is covered in our comparison of evaporative air coolers and portable air conditioners.

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Further reading