Home Inspector with Superior Home Inspections - Greater Albuquerque Area InterNACHI 10041206

Well, today I must report another casualty, one in which a Swamp Cooler, or Evaporative Cooler was mounted on a roof surface. I recently wrote a blog about mounting these things on a roof - here. It may not be very timely because we are in winter, but this one caused a major defect and I see it all the time. This roof surface got Swamped!

It just boggles the mind, it almost always ruins the roof surface, because they all leak at one time or another! What is an Evaporative or Swamp cooler? An evaporative cooler or swamp cooler cools the indoor air using evaporation. 

It lowers the dry-bulb temperature of the indoor air. When the blower fan turns on, it draws air from outside.  The air passes over the wet pads and blows into the interior.  The water in the pads absorbs the heat from the air as it passes through them.  This causes some evaporation of the water, and the temperature of the air is lowered.  It is this creation of a low dry-bulb temperature that produces the cooling effect. They are pretty effective here in our dry climate.

Evaporative coolers should not be installed where there is high humidity.

They are often mounted on top of a roof, but that is the worst place to mount them. They can be inserted in a window opening or sidewall of a building, or installed on a pad beside the house as well,which would be my preference. 

Maintenance involves keeping the unit clean by cleaning or replacing the water pads, and cleaning the water sump tray and fan. Problem is, if it's on the roof, it's kind of a out of sight, out of mind thing so if it begins leaking (and it will) you could possibly not even know it till it's too late!

This roof surface has been ruined by the water constantly running down these shingles. The chemicals in the public use water has done a job on the protective granules on these shingles!


To understand better, this is how a shingle in constructed; There is an asphalt-impregnated base, or mat, either of a cellulose material (for regular shingles) or fiberglass (for fiberglass shingles), it is then covered with a heavier layer of asphalt. Then, a layer of granules is pressed into the surface as protection from the Suns ultraviolet light.

Once the protective granules are gone, the life of the mat underneath will be significantly reduced! The Sun will dry it up and make it crispy in a very short time. That is happening on these roofs and the owner cannot even see it unless he gets up there and checks... he's getting Swamped!! 

So why do they mount them up there.... please Mr. Contractor, I would love to know!




Posted by

Fred Hernden 


 Superior Home Inspections





 Albuquerque, Rio Rancho New Mexico and surrounding areas...


“My mission is to provide superior quality home inspections to my clients to ensure peace of mind so they can confidently make the largest investment they may ever make!"


Please visit my website at: www.SuperiorHomeInsp.com for details!







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Myrl Jeffcoat
GreatWest Realty - Sacramento, CA
Greater Sacramento Real Estate Agent

We don't see evaporative coolers very often here in Sacramento, but they were once the rule of the day!  There's no question they can cause issues to the roof. Recently, I've seen a great deal of roof damage caused by solar panels used to heat swimming pools.  In fact there seems to be a high percentage of those that leak onto roofs.

Feb 09, 2016 10:32 AM #1
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Again, my experience with those things is no experience.

But wait!  If it's going to leak the best place is the roof, with shingles made for handling water!

Oh yeah, that shingle damage thing. 

So keeping it clean works?

Feb 09, 2016 08:07 PM #2
Fred Hernden, CMI
Superior Home Inspections - Greater Albuquerque Area - Albuquerque, NM
Albuquerque area Master Inspector

Myrl - Yes, they leak too! They are usually connected together with a rubber connector, they dry up, crack.... you know the routine 

Jay - It helps, but it's a pan of water on your roof, too many connectors, water running down the pads... it's gonna leak 

Feb 09, 2016 10:40 PM #3
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Albuquerque area Master Inspector
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