“Will my household AC system run more efficiently (perhaps cycle on/off fewer times, or the compressor won’t have to run as long when it cycles on) by shading the compressor?”

There’s been some debate for some time now regarding whether homeowners should cover their air conditioner. Most air conditioning manufacturers don’t specifically recommend covering the air conditioner. However, depending on where you live, especially if it’s an area prone to ice and snow, covering your unit may be a good idea.

Unfortunately, there is no perfect answer. The truth is, it’s entirely up to you. There are good reasons you should cover your air conditioner, as well as good reasons not to cover it. So, while we can’t give you a concrete answer, we can give you the pros and cons of covering your air conditioner so you can decide which course of action you’d like to take.

  • PROS

Covering your air conditioner provides protection from falling ice. It may also keep the coils cleaner so it runs more efficiently for the summer.

A cover stops debris like leaves, sticks, branches and other yard waste from becoming lodged inside the unit.

Covering the condenser prevents water from resting directly on the coils and freezing, which could damage them.

  • CONS

Trapped moisture can lead to rusted components if the condensation freezes. It may also bend the condenser coils.Depending on where your unit is located, it may be susceptible to damage caused by ice and other debris falling from the roof or eaves.

A cover can create the perfect habitat for critters, such as mice, to nest in during the winter, leading to chewed wires and damaged components.

Why this is a natural question to ask

First, a little explanation about air conditioners. That metal noisemaker that sits out in back or on the side of your house is called the condensing unit for air conditioners. The compressor is one component in that box, but the condensing coil and a few other parts are there, too.

The condensing coil’s job is to dump the heat picked up inside the home to the outdoor air. (If you have a ground source heat pump, that heat gets dumped into the ground rather than the air, and you won’t have an outdoor unit like the one shown above.) The hotter it is outdoors, the harder it is to dump that heat and the more you’ll spend keeping your house cool.

Hence the question, can shading your air conditioner’s outdoor unit provide significant savings? And the answer is yes and no. It depends on what type of shading we’re talking about, but for the type of shading most people are thinking about when they ask that question, the answer is no.

Why the answer leans mostly no

Shading the outdoor unit with a structure as shown below will reduce the direct solar gain from insolation but won’t do a whole lot for the air temperature around the unit.


If you really want to improve the efficiency of your air conditioner, your opportunities are much greater if you look to your duct system. By fixing disconnected ducts, flacid flex, uninsulated boots, and more, you may be able to cut your air conditioning bill in half, depending on how bad your particular ducts are. And they most likely are bad.