Reuben's Home Inspection Blog

Should I Cover My Air Conditioner?

October 20th, 2009 | 8 comments

Summer is gone, fall is here, and it’s time to get around to all the fall chores – put up your storm windows, turn off the outside sillcocks, cover up the air conditioner… wait, scratch that last one.  Don’t waste your time or money installing a cover on your AC unit.  I’ve already seen people start to cover their air conditioners this year, but there’s no need to.

Air Conditioner Cover

Why do people even install air conditioner covers?  One company that sells covers claims that their AC cover “protects from dirt, hail, snow, ice, nesting animals, moisture, bitter cold, and harsh sunlight.”  Wow, that list makes me not want to go outside.  Let’s review those one at a time.

  • Dirt – When the fan on an AC unit is running, air will be sucked in on all sides of the unit, and this is when most dirt and dust accumulates.  When the unit is just sitting dormant, outdoor contaminants don’t get sucked in.
  • Hail – We don’t get hail during the winter here in Minnesota.
  • Snow – Snow won’t hurt the AC unit.
  • Ice – Ice won’t hurt the AC unit.
  • Nesting Animals – I’ve never seen this happen, and I can’t figure out how it could.
  • Moisture – C’mon, seriously?
  • Bitter Cold – Get out.
  • Harsh Sunlight – Ok, that’s enough.

AC units are designed to be installed outdoors all year ’round.  They are designed to hold up to the elements – they don’t need a cover.  The manufacturers have already taken things like ‘harsh sunlight’ in to account.  If you need proof, just check the web sites of some of the larger manufacturers, such as Rheem and Lennox.  They specifically say their units shouldn’t be covered, because the covers can trap moisture, which can cause damage to the unit.

If you want to keep stuff from falling in to the top of your air conditioner during the fall, just put something on top of it, like a piece of plywood.  While it seems a little laughable, even a makeshift cover like the one pictured below will work just fine, as long as you do something to keep it from blowing off.  This will keep debris from falling in the top of the unit, and it won’t trap moisture.  If you want something that doesn’t look silly, install a very short cover.

Makeshift Air Conditioner Cover

Reuben Saltzman, Structure Tech Home Inspections – Email Wayzata Home Inspections

8 responses to “Should I Cover My Air Conditioner?”

  1. Brenda Beard
    October 1, 2011, 11:39 am

    Thanks for shedding light on this subject. I have been debating whether or not to cover my A/C unit. Is there any advantage in covering a through the wall unit?

  2. Reuben Saltzman
    October 1, 2011, 7:49 pm

    Hi Brenda – covering your through-wall unit during the winter might help prevent some cold air from coming in to the house, but I’m guessing you already insulate the inside part, so it probably wouldn’t make a huge difference.

  3. Tom
    November 16, 2011, 1:33 pm

    Nice article. I had a Trane unit installed for my home in Northern Ohio a couple of years ago. We do get quite a few leaves in the fall as I live in a wooded area though. There’s an Amish tarp shop near my house and I had them make me a cover for under 30 bucks. I only install it in the Fall to prevent the leaves from accumulating in the unit. I then remove it once the snow flies. This really helps keep debri out of the unit but doesn’t prevent the unit from “breathing” as it should during the winter. In the early spring, I lightly spray the unit’s internals with the garden hose but that’s the extent of my AC maintenance. I have consulted the sales rep numerous times and he ensures me that AC covers do not effect their warranty in any way. In other words, Trane will honer their warranty even if you don’t cover your unit – so don’t waste your money.

    As a side note, I used to live in Southwest Florida. Down there, our water softeners were even outside. So you can’t convince me that an AC unit in Northern Ohio is subject to any more abuse than a water softener in South Florida’s humid climate.

  4. Dorene Mitchell
    November 13, 2012, 8:12 am

    Hello I have several window units in a rental property. The ones on the west wall get a lot of winter wind. I usually cover them but once in a while it would be nice when the temp goes up the tenants can turn the unit on to freshen the air. Does the wind and cold get through that much? I do pay the heat in the building so I am concerned. Thank you

  5. Reuben Saltzman
    November 15, 2012, 6:25 am

    Dorene – yes, a lot of cold will get through these units. If it were my property, I’d keep them covered.

  6. Hardin
    January 16, 2013, 4:48 am

    I think it depend on the area if you weather is like raining then It make sense to cover it, anyways you can cover it to protect from dust to.

  7. Janette
    September 24, 2013, 5:33 pm

    I live in southern Oklahoma and while the area we live in has always been dusty, I have had a recent problem with large amounts of dust coming into my home. The home is a rental and about six months ago the outside unit was replaced with a larger used unit and from them on the dust collection has been unreal. I have respiratory problems and actually feel like I’m breathing dust when I’m at home. I cough, sneeze and am short of breath more at home. Any suggestions? Rentals area few and far between here and it took our landlord months to finally replace the unit that had quit working.

  8. Reuben Saltzman
    September 24, 2013, 5:34 pm

    Hi Janette, I’ve never had experience with something like that.

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