Evaporative Cooler - Swamp Cooler


Evaporative Cooler - Swamp Cooler

How evaporative coolers work:

Evaporative cooler block diagramIn low humidity regions, evaporating water into the air provides a natural and energy-efficient means of cooling. Evaporative coolers, sometimes called swamp coolers, cool air by blowing it over water-saturated pads, causing the water to evaporate. The cooler air is blown into the home and pushes warmer air out through windows that have been opened slightly. Unlike central air conditioning systems that recirculate the same air, evaporative coolers provide a steady stream of fresh air into the house.

Evaporative coolers cost much less than central air conditioners and use about a third as much electricity. However, they need more maintenance than air conditioners and they're suitable only for areas with low humidity.

Advantages of an Evaporative Cooler

  1. Coolers are economical to operate, using one-third the energy of refrigerated air-conditioning.
  2. Installing a new evaporative cooling system adequate for a 1,500-square-foot home costs about $700. For the same home, installing a new air-conditioning system, using existing duct work, costs about $2,500.
  3. Most cooler maintenance and repairs can be accomplished by the homeowner.
  4. Most cooler replacement parts (pads, belts, etc.) are nominal in cost when compared to air-conditioning system replacement parts.
  5. Coolers bring fresh, cooled, outside air into the home.
  6. Coolers provide a healthy environment for plants.

Disadvantages of an Evaporative Cooler

  1. Coolers use on-site water, a non-renewable resource in some parts of the world, for cooling.
  2. Coolers are aesthetically unattractive if not maintained and overflow of concentrated salts from the
    cooler can damage roofs.
  3. Air velocity when operating on high speed may cause annoying noise.
  4. Open windows to exhaust air may be a security hazard. This can be overcome by installing ceiling
    vents. Adequate attic ventilation is necessary for ceiling vents to function properly.
  5. Cooled air may bring dust and pollen into the home causing discomfort for allergy sufferers. Growth of microorganisms such as molds on the cooler pads may cause allergy problems in sensitive individuals.
  6. Coolers require regular maintenance, difficult if the cooler is roof-mounted.


Most evaporative coolers are installed on the roofs of houses. However, many experts Ground mounted evaporative coolerrecommend they be installed on the ground, which permits for easier maintenance and less risk of roof leaks.

Smaller horizontal-flow coolers are installed in windows to cool a room or section of a home. These portable evaporative coolers work well in moderate climates, but may not cool a complete room in hot climates. Room evaporative coolers are becoming more popular in areas with milder summer weather as they can reduce the temperature in a single room by 5°–10°F.

Portable evaporative coolers on wheels have the advantage of portability, but their cooling ability is limited by the humidity within your home.


Operating an Evaporative Cooler

An evaporative or "swamp" cooler should have at least two speeds and a vent-only option. The vent-only operation, lets you use the evaporative cooler as a fan during mild weather.

You control the cooler air movement through the house, by adjusting window openings. Open the windows or vents on the opposite side of the house to provide 1–2 square feet of opening for each 1,000 cfm of cooling capacity. If the windows are open too far, hot air will enter. If the windows are not open far enough, humidity will build up in the home.

You can regulate both temperature and humidity by opening windows in the areas you want to cool, and closing windows in unoccupied areas. If security is an issue, you can install ducts in the ceiling. These ducts open to vent warm air outside as cooler air comes in from the evaporative cooler.

Filters are usually available which will remove most of the dust from incoming air for homeowners concerned about allergies. Ask about this feature if it's a concern to you.
Portable evaporative cooler

Evaporative cooler maintenance

Follow the manufacturer's instructions. Drain and clean your evaporative cooler regularly. The build-up of sediment and minerals needs to be removed. Coolers reguire a major cleaning every season.

The more a cooler runs, the more maintenance it will need. Check the pads, filters, reservoir, and pump at least once a month. Replace the pads at least twice during the cooling season, or every month during continuous operation.

Some cooler pads can be cleaned with soap and water or a weak acid according to manufacturer's instructions. Filters should be cleaned when the pads are changed or cleaned. Be sure to disconnect the electricity to the unit before servicing it.


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