Evaporative Air Cooler is also commonly known simply as air cooler. Unlike air conditioning, air cooler does not have any compressor in the system. It basically consists of a fan that takes in the air from the environment and passed it through a layer of damp pads before discharging it out to the room.

It can be used to lower the room temperature up to 30°F depending on the temperature and the humidity of the room. Some coolers are used together with air conditioning systems to increase the efficiency of the air conditioner. One advantage of evaporative cooler is that it used only 10%-20% of the power consumption of an air conditioner.

Principles of Evaporative Air Cooler

This equipment works best in places where the environment is hot and dry. Factories and workshops that have large area of which spot cooling is required in certain location can make use of this device. It is not able to work well in humid condition as the air has already been saturated with water moisture. In order for air to be cooled, it has to evaporate some of the water.

The device has a fan that sucks in the hot and dry air from the room. This air is then passed through a layer of specially made damp pads. The pads are kept damped by the use of a water pump that continuously circulate water inside this equipment.

Some equipment has container that stores the water and can be used for up to quite a number of hours before refilling. In bigger equipment where bigger space need to be cooled, piping work to obtain the water directly from the water piping supply need to be done.

As the air passed through the damp pads, it picks up some moisture from the pads. As a result, the temperature of the air can drop sometimes to a maximum of 30°F depending on the temperature and humidity of the room.

This conditioned cooled air is then discharged to the room by the same fan. As the air passes through the pads, it is filtered and contaminants such as dust, dirt and other pollutants are stuck on the surface of the pads. You will then get a cleaner and cooler air.

A mechanical control type air cooler


Some of the places that may be able to utilised evaporative air coolers are listed below.

  • Schools, waiting rooms, supermarket and warehouse.
  • Metallurgy, hardware and leather industries.
  • Indoor installation in places where high humidity is required.
  • Kitchen, underground parking and pay station.
  • Shoemaking, printing and dyeing, plastic, clothing, press and printing, packaging and food processing industries.
  • Library and outdoor dining.

The sample of a typical pads that is used to filter out contaminants and absorbing energy from the hot air.


There are many types of air cooler that are sold in the market these days. Some of the features that you may want to look before purchasing one are:

  • Water level control and indication.
  • Low, Medium, High or even super high fan speed control.
  • 24-hour operation.
  • Auto-wash during on/off and at programmed intervals.
  • Programmable on/off function.
  • Airflow can range from a few hundred cubic meter/hour to 18,000 cubic meter/hour depending on the size of the area that needs to be cooled.
Editorial Contributors
Alora Bopray

Alora Bopray

Staff Writer

Alora Bopray is a digital content producer for the home warranty, HVAC, and plumbing categories at Today's Homeowner. She earned her bachelor's degree in psychology from the University of St. Scholastica and her master's degree from the University of Denver. Before becoming a writer for Today's Homeowner, Alora wrote as a freelance writer for dozens of home improvement clients and informed homeowners about the solar industry as a writer for EcoWatch. When she's not writing, Alora can be found planning her next DIY home improvement project or plotting her next novel.

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Roxanne Downer


Roxanne Downer is a commerce editor at Today’s Homeowner, where she tackles everything from foundation repair to solar panel installation. She brings more than 15 years of writing and editing experience to bear in her meticulous approach to ensuring accurate, up-to-date, and engaging content. She’s previously edited for outlets including MSN, Architectural Digest, and Better Homes & Gardens. An alumna of the University of Pennsylvania, Roxanne is now an Oklahoma homeowner, DIY enthusiast, and the proud parent of a playful pug.

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