Evaporative Air Coolers: The Pros and Cons

If you live in a hot, dry climate, evaporative air coolers are a very good value. Like any other commodity, there is a trade-off in convenience.

Evaporative coolers, also called swamp coolers or desert coolers, are a good choice for homes in hot, dry regions. They are affordable and relatively easy to install and maintain.  Homeowners typically enjoy savings of 65% or more on their utility bills over conventional refrigerated air conditioning, and do not have to add a humidifier to their systems. 

In arid climates like the southwest American states, Africa, and parts of Australia, the best way to cool your home was always with water.  People would wet the walls of their adobe or mud homes, which would hold the dampness and keep the house cooler for long periods.  Another trick was to hang wet blankets over the doorways so the wind would blow through them, cooling the house.  When electric power became plentiful, the idea was developed into evaporative coolers.

Basically, an evaporative cooler is simply a large metal or plastic box with a solid top and a water reservoir in the bottom.  It has a squirrel cage in the middle, turned by a small motor – generally ¾ horsepower and with two speed variables.  An immersed pump forces water up through tubing to drip gutters above the vented sides of the box, allowing constant wetting of pads that cover the vents.  When the unit is turned on, the motor turns the squirrel cage, drawing air through the wet pads and blowing cooled, humidified air into the home.


Outfitting your home can cost anywhere from $500.00 to $1500.00, depending on the size and type. Swamp cooler output is measured in CFM’s, or Cubic Feet per Minute of air moved. A simple formula to ensure adequate size for your needs is to measure the cubic feet of the home or room you are cooling, and then divide by two.  So a typical 1500 square foot home with 8 foot ceilings would need 6,000 CFM’s to effectively cool the house [1500 x 8 = 12,000, % 2 = 6,000 CFM's needed].  Since the size cooler needed for this is prohibitive, you normally install two coolers, each rated at 3,000 CFM’s.

Unless you want the huge commercial models that require 220 wiring, swamp coolers typically plug into normal 110 electrical outlets.  They are connected to a water supply, usually with a simple T-valve installed on an outdoor faucet, with ¼ inch copper line to the cooler reservoir.  The water level is controlled by a float, similar to a toilet tank.  A double plug inside the box accommodates the motor and immersible pump.  Pads are purchased by the roll or pre-cut, and installed by removing the vented sides individually.

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Published in: Home Improvement


RSSComments: 7  |  Post a Comment
  1. Very interesting. Here in Minnesoat I fear that the refrigerated units are the only way to go, but when I lived in western North Dakota this type of unit would have been very useful.

  2. Great discussion about these air coolers… it is so interesting that you posted this today because I was just talking to someone about them a few days ago : ).

  3. We don’t really need AC units here in the UK!

  4. I just want a normal window air conditioner in our apt that will work!!!

  5. Lucky you in the UK! We didn’t either in the midwest. When we moved to the desert we got a whole education!

  6. Useful article. AC is essential in my place too.

  7. Informative article, we only need air conditioning for a few weeks every year if we are lucky!!

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