Swamp Cooling (Evaporative Cooling)

This article is written and posted by Thom Culpepper, Owner of TLC Professional Inspections, Inc., and the views shared in this blog are a culmination of research and over 3,000 Home Inspections in Tucson and the surrounding areas.

Some of us here in Tucson have an antiquated way of cooling our homes.  Evaporative Cooling ( Swamp Cooling ).  A unit is primarily located on the roof, with water pumped onto the roof to the cooler, then a pump saturates pads on the 1, 3 or 4 sides depending on the model, and a fan sucks air through the wet pads, and through evaporation, cools the air being blown into your house.  The effectiveness is directly related to the amount of humidity in the outside air.  The lower the humidity outside, the more effective the swamp (evaporative cooler) is at cooling your house.   In Tucson, spring and fall are when the swamp cooler is most effective.  Monsoon season in Tucson is the worst time.

Lets say the swamp cooler is at it’s most effective. Low humidity outside and such.  The swamp cooler will cool about 20 degrees less than the outside ambient temperature.  So, if it is 90 degrees Fahrenheit outside, the cooler should cool the inside of the house to 20 degrees less than the outside temp, or 70 degrees.

Now, some people who grew up with the swamp cooler prefer the extra moisture in the house that the swamp cooler adds,  and they say that the swamp cooler uses less energy than an air conditioner.  As a home inspector though, they are responsible for more roofing problems, such as leaks, deterioration of the roofing coating, wood rot from overflowing coolers, and are a maintenance problem. One may save on energy costs if you have an older A/C, but there really is no difference with the newer A/C’ s on the market now.  You are actually spending more money with roof repairs, water and maintenance of the unit.

I have to admit they are truly an easy machine, consisting of a small pump, pads and a motor with a fan.  If you are relatively handy, you only have to go up onto the roof each month to make sure the pads are being saturated, the fan and pump are working, the float is working so it doesn’t overflow onto the roof.  I don’t know who invented them, but they had their time in the spotlight, but with the new energy efficient A/C ‘s out there, it may be time to do away with them all together.

As a property owner and a Home Inspector, I see so much damage to the roof and to the drywall in homes from poorly maintained swamp coolers, not to mention the wasted water.  All it takes is a small mal-adjusted float to have water leak constantly onto the roof.  This constant water on the roof deteriorates the roofing material, and left unchecked, causes leaks into the home.



If you own an evaporative cooler and you use it through the summer, make sure it is maintained on a regular basis, attach an old garden hose to the overflow pipe within the cooler and let it drain off the roof instead of onto the roof, and save a great deal of costly repairs. The OLD saying was that swamp cooling was cheaper to run than an air conditioner, but with today’s energy efficient air conditioners, that OLD saying no longer applies. Again, if you take into consideration the water damage, the water wasted, the servicing that is required, and the newer energy efficient cooling systems, why not look into a true air conditioning system and see the difference.

Sometimes, change is good!

(you can contact Thom Culpepper @ Thom@TLCProinspections.com  )


One Response to Swamp Cooling (Evaporative Cooling)

  1. Hi! I know this is kind of off topic but I was wondering if you knew
    where I could find a captcha plugin for my comment form? I’m using the same blog platform as yours and I’m having difficulty finding one?
    Thanks a lot!

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