Choosing a Swamp Cooler

The idea behind swamp coolers work is basic Physics. As water evaporates, it cools any object it’s in contact with as well as the surrounding air. Your body uses this principle to help regulate your temperature through perspiration and you may have felt it if you’ve ever put on a damp shirt and stood in a breeze or simply walked outside with wet hair. Since swamp coolers cool using simple evaporation not pressurized gases, they are both energy efficient and environmentally friendly. No wonder with the high costs of electricity and our growing concern for the environment, the idea of swamp coolers as a totally natural way to cool a home is gaining popularity.

Using a swamp cooler

  • Unfortunately, swamp coolers won’t work well everywhere and to use one you need to live in the right location. Since swamp coolers can only cool hot, dry air, they work best in arid climates. In regions where the air is naturally humid, swamp coolers won’t cool but instead will make a home feel moist and clammy. What this means in the US is swamp coolers are best suited for the southwestern regions of the country and in most cases, don’t work well east of the Mississippi.

Sizing a swamp cooler

  • You can get swamp coolers sized to cool only an individual room or have a large central unit installed on the roof or the side of your home that can cool your entire house.
  • Similar to air conditioners, the size of a swamp cooler is important in determining how well it will work in a home. A small, portable unit isn’t capable of cooling an entire house, but choosing a unit that is too large will end up adding too much moisture to the air and make a room feel uncomfortable.
  • Swamp coolers are sized/ rated based on the number of cubic feet of air a unit can move in a minute (CFM) and according to manufacturers, a properly sized unit should be capable of changing the air in a room or house between 20 to 40 times in an hour.
  • You can calculate the proper sized unit for your situation by first calculating the cubic capacity of your room or home then dividing that number by 2. For example, if you have a room that is 20 feet long, 12 feet wide and 8 feet high, the cubic capacity is 1920 cu. ft. (20 X 12 X 8= 1920). Dividing 1920 by 2 tells you the proper sized swamp cooler for that room should have a capacity of 960 CFM.

Installation considerations

  • Installing a central swamp cooler for the entire house can be complex since he unit needs to be mounted either on the side or the roof of your home plus have access to both electricity and a supply of water.
  • As well, depending on your home’s interior, for a central unit to work well you may need to install additional ducting to distribute the cooled air throughout the house. In homes with an open design open delivering the cooled air to a central location is probably sufficient to cool the entire house. However, homes with separate and closed rooms will likely need additional ducts. Standard hot air heating ducts are too small for a swamp cooler to operate efficiently, so even if ducting is in place, it doesn’t have the capacity to move the moist, cool air.

Murray Anderson is an experienced freelance writer with over 500 articles published on the web as well as in print magazines and newspapers in both the United States and Canada. He writes on a wide range of topics and is a regular contributor to He can be contacted at