Can a Window AC Unit Get Wet? Here’s What You Need to Know

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When summertime comes around, hot weather makes it necessary to have air conditioning. But what happens to your window AC when it rains outside? Is it safe for your window AC to get wet? What about getting sprayed with a water hose?

Window air conditioners can get wet. Water won’t damage the AC unit or affect its performance.  The window AC’s internal components are resistant to water—so rainwater or getting sprayed by a water hose won’t damage it. The only time water will damage a window AC is if there is standing water inside the unit, or the unit gets completely flooded.

In this article, I’ll discuss everything you need to know about getting water on your AC. I’ll also discuss window AC drainage and how to keep your window AC out of the weather.

Will rain damage a window AC unit?

Rain will not damage a window AC unit as long as it properly drains. The internal components inside a window AC are sealed from water. The only way that rainwater would damage a window AC is if the water doesn’t drain out of the case. The standing water will eventually corrode the case.

When it’s raining outside, rainwater is actually your smallest concern. Falling sticks and branches from nearby trees pose a much larger threat to your window AC since they fall and cause damage. That’s how storms can cause damage to your window AC.

After it storms, go outside and take a look at your window AC. Make sure that it’s not damaged and clean out any sticks and debris from it.

Also, take a look to see if the window AC is draining properly. Make sure there are no sticks or leaves blocking the drain hole.

How to keep rain off of your window AC

If you want to keep your window AC protected and out of the elements, then you need a window AC cover for that.

Usually, there is no need to keep the rain off of your window AC. However, if you won’t be using the AC for a while then you can cover it to keep it dry.

Be advised: If you use a cover on your window AC, then you can’t run the AC. A cover should only be used when the AC isn’t running. Most people cover their window AC during the winter.

While a window AC cover will keep your window AC dry, there is another reason why to use a cover: debris.

Debris poses a much greater hazard to the condition of your window AC. Here are a few examples of debris that your window AC might come into contact with:

  • Leaves
  • Sticks
  • Animals & Nests
  • Snow & Ice
  • Hailstones

Imagine turning on your AC when there are sticks inside—all sorts of weird noises from sticks bouncing around. Worse yet, one of those sticks has the potential to cause damage.

Also, debris such as rotten leaves will eventually corrode your AC from the inside out. 

Worse yet, imagine your window AC getting hit by a hailstorm—it might get destroyed. That’s why it’s important to keep your window AC covered if you aren’t using it.

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One more thing—don’t use a DIY window AC cover. Covering your window AC with a piece of plastic such as a trash bag can cause damage. A trash bag won’t drain water, so there is a chance that your window AC may end up sitting in a pool of water after a rainstorm.

Window AC covers are designed to drain water out. So as long as you use a window AC cover that’s designed for that purpose, then it should drain properly.

What is a window AC drip cushion used for?

A window AC drip cushion is used to prevent noise from rain falling on your AC. As rain falls, the raindrops make a sound on the hard metal surface of the window AC. A drip cushion absorbs the raindrops so they don’t make noise when hitting your window AC.

Using a drip cushion is fine as long as you don’t cover any vents on your window AC. If there is a vent on the top of the AC, then you’ll need to cut a piece out of the drip cushion so that it doesn’t cover the vent.

Most drip cushions attach to the top of your window AC using a magnet or an adhesive such as glue. When installing a drip cushion, make sure that the window AC is clean. Use a cloth and some rubbing alcohol to ensure that there are no oils on the surface of the window AC. If there are any oils or grime on the window AC, then the drip cushion adhesive won’t stick.

You’ll also need to cut the drip cushion to the proper size to fit on your window AC. Be sure to get a drip cushion that is a little bigger than the top of your window AC, that way you can cut it down to size.

What happens if your window AC is full of water after it rains?

If your window AC is full of water after it rains, then your AC has a drainage issue. There should not be any standing water inside your window AC after it rains.

To fix the drainage issue, find the drain hole in the bottom of the window AC. The drain hole should be close to the back.

Inspect the drain hole and make sure there is nothing blocking it. If there is any debris in the window AC drain pan, remove them and unblock the drain hole.

Another issue is if your window AC isn’t tilted backward. Your window AC needs to be installed at a slight angle in order to allow water to flow backward out of the unit. This is to allow condensation from the evaporator coil to drain out of the back of the unit. It’s also to allow rainwater to drain out of the unit.

If your window AC is not installed at a slight angle, then water will build up inside the unit. Standing water will eventually corrode the inside of your window AC. Worse yet, if your window AC is not tilted back, then water may drain out of the front of the unit instead.

Hi, my name is Trey Lewis and I’m the founder and chief editor at HVAC Training Shop. My goal for this website is to help homeowners troubleshoot and maintain their home’s HVAC systems. Whether it’s changing an air filter, troubleshooting a blower motor, or just buying a new humidifier, I want to make sure that you’re covered.

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