Should I Cover My Air conditioner?

We all have that meticulous neighbor that gets out the fancy air conditioner cover in the fall and wraps up the compressor unit on their air conditioner.  Is this really necessary?  The people that sell covers would certainly like you to think so, but the manufacturers of the AC units don’t agree (so neither do I).

What’s the reasoning behind installing an AC cover?  According to one manufacturer, “Our AC cover protects from dirt, hail, snow, ice, nesting animals, moisture, bitter cold and harsh sunlight.”  News flash: the compressors for AC units can only be installed outdoors, and they are designed to be outdoors all year round!  They are designed to hold up to snow, bitter cold, harsh sunlight, etc.  I’ve personally never seen a nesting animal in an AC unit, and hail only comes with thunderstorms, which we don’t have in the winter in Minnesota!

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Some of the largest manufacturers of air conditioners, such as Rheem and Lennox, specifically say their units shouldn’t be covered.  The covers can trap moisture, which can cause damage to the unit.  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.

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If you want to keep leaves and other debris out of your air conditioner during the fall, I suggest putting a piece of plywood on top of the compressor.  This will keep debris from falling in to the top of the unit, but certainly won’t trap moisture.  If you want something that looks a little nicer, install a very short cover.