How to Cover a Window Air Conditioner for Winter

a window AC unit covered with a tarp
  • 1-3 hours
  • Beginner
  • 25-50
What You'll Need
Duct tape
Foam insulation
Plastic/vinyl tarp
Garden hose/spray bottle
Vacuum cleaner with attachments
Putty knife
What You'll Need
Duct tape
Foam insulation
Plastic/vinyl tarp
Garden hose/spray bottle
Vacuum cleaner with attachments
Putty knife

A window air conditioner unit is a lifesaver in the sweltering summer when every day lasts forever and temperatures soar. But when winter sweeps in, your AC unit can really take a beating. It's important to cover window AC in winter so they'll be ready to go again in summer.

A window air conditioner cover is an excellent way to prevent cold air from leaking into your house during the winter. This cold air can be an added drain on your finances.

As the air conditioner sits in the window, it is hard to seal the window from winter’s chill, making the heater work twice as hard and increasing your electric bill. A cover will seal the window. You can make an indoor or outdoor cover. If you are ambitious, you can make both.

How to Cover Window AC in Winter

When you know you're done with your AC unit for the season, go ahead and winterize it before the weather starts to get really cold. If you take a few steps to prepare your unit with a window air conditioner winter cover, your AC will continue to keep you cool for many summers to come.

Step 1 - Turn the Air Conditioner Off

You'll want to open the control panel and turn off your AC unit. This will prevent it from turning on during an unseasonably warm day, which can cause the unit to freeze when winter temperatures normalize.

Double check that your air conditioner is in the “off” position. Remember to turn it on again when the summer comes around, or you could spend some anxiety-ridden moments wondering why the unit isn’t kicking on.

Cut the power to the outdoor condensing/compressor unit. Most often, a quick disconnect circuit box is located within three feet of the outdoor unit. Open the box and either flip the circuit breaker or pull the disconnect plug to cut the power.

In some applications, you can also cut the power to the indoor evaporator/air handler, but that will depend on if your furnace uses its blower to distribute heated air through your home. In that scenario, you would not want to turn off the blower unit.

Step 2 - Wash the AC Unit

Someone cleaning off an air conditioner frame outside.

Before you seal the outside part of your air conditioner, you need to clean out the debris. You can do this with a high-pressure hose or your hands; just get out as much gunk as possible. You will also need to don your work gloves and remove any foliage, weeds, or other debris from around your outdoor condensing unit.

Use a water hose to thoroughly rinse both the outside and inside of the condensing unit to remove dirt, bird droppings, dust, and leaves.

Use a garden hose or a large spray bottle to thoroughly clean your AC unit on the exterior side. Wash it with warm, soapy water. Liquid dish soap will work fine for this. After the unit has been cleaned of dirt and debris, rinse it off with plain water. Let the unit dry completely before you move on to the next step.

After this, lightly hose down the unit and scrub down the dirt where required. Using a vinegar-and-water solution can assist in cleaning the dirt and stains. Use a vacuum's brush attachment and an old toothbrush to clean the fins.

Step 3 - Clean the Interior

While it’s turned off for the season, take the opportunity to clean the interior side of your AC unit. Dust, hair, and lint have a way of drifting toward air conditioner window units, so they should be cleaned periodically.

Remove the front grille of the unit. If the grille doesn't come off with a little bit of pressure, use a putty knife to pop it out of place. Wash the grille in warm, soapy water and then rinse it clean. Now you can use a vacuum cleaner attachment to get dust, hair, and dirt out of the inside of the unit.

Stubborn dirt can be removed with a dry scrub brush or wire brush. Use the vacuum to clean below the unit (dust will come down from it), replace the grille once it's thoroughly dry, and you're done.

For a soap, you can use any mild household detergent, or pick up an AC specific cleaner, like this one on Amazon.

Avoid harsh cleaning products like bleach and TSP, since they could potentially damage sensitive cooling components.

Step 4 - Insulate the Window AC

Window AC insulation will protect your unit from freezing during the cold winter. If temperatures drop particularly low in your area, you may consider placing two layers of insulation instead of one.

Good drywall insulation around the window will help stop cold air from sneaking in. For the tricky spaces between the AC and the window, you'll want to use some kind of foam if you're keeping the unit in place through the winter.

Surround all exposed exterior pipes with foam. Small sheets of insulating foam are available at home improvement stores. Cut your foam into pieces, and secure it around the pipes with duct tape. You should add some strips of foam around the unit itself where it joins the window.

Make sure to insulate both the copper refrigerant lines as well as the PVC condensate or drain line. Rubber or foam pipe insulation is easy to install and available at most home improvement centers.

Simply cut the insulation to the correct length and wrap it around the applicable pipe. Wrap a piece of duct tape around the pipe insulation where needed to hold it in place.

window AC unit covered with tarp

Step 5 - Cover the Entire Window AC Unit

Before you begin cutting a cover for the unit, you need to know the dimensions of your air conditioner. Jot down the height, width, and depth of the outside element and sketch it. In this sketch be sure to include the location of any hardware.

Next, cover the entire air conditioner unit with plastic or vinyl. This can also be secured with duct tape. Take extra care around the perimeter of your cover to ensure that it is waterproof. Some AC units come with covers, or covers can be purchased for them separately, but using plastic to make a DIY cover also works.

Covering your air conditioner this way will protect the unit, but it has the added benefit of insulating the window where the unit is installed. This will keep cold temperatures and breezes out during freezing winter days, which can ultimately help reduce your energy bill. Insulation will also help minimize condensation, which can reduce your unit's cooling efficiency.

You can also use styrofoam. To do so, use a razor knife and cut the styrofoam into five parts. Each part should have slightly larger measurements than the side of the air conditioner it corresponds to. There should be about an eighth of an inch of leeway in the final product. This will ensure that, while the cover will fit on the machine, it will be snug. Be sure you account for any hardware.

Use the construction adhesive to form a box. This box should have slightly larger dimensions than the outside portion of the air conditioner. Once the box is completed, place it on the air conditioner and seal it. There should be no room for the air to enter of escape the building. The adhesive you use should specify that it will not peel the paint on your house.

If you want an off the shelf solution, you can pick up a thermal winterizing cover at any home improvement store in several different sizes, so you will need to measure the dimensions of your air conditioning unit before you buy it.

Finally, find a safe place to physically put the unit. If you don't have an attic to store your AC unit, you can keep it in a finished basement, or an interior closet. Don't keep it in a garage or unfinished outbuilding, where it can suffer damage from weather, or become a home for pesky pests.

Maintaining Your Air Conditioner

A repairman working on an air conditioner.

Physically inspect the exterior of your AC unit every week, and particularly after fresh snow or storms. Remove twigs, brush snow off the unit, and check that the cover is secure. If you find the cover loose or moved, remove it to inspect the unit. Remove debris and water, if necessary, and recover the unit securely.

When weather permits, you should also remove the cover and check for any wildlife nesting inside your unit. The covered unit is an attractive and warm place for animals looking for an escape from the cold. If any are present, remove them in the appropriate manner and recover the unit.

When the warm weather returns and it's time to start up your unit, it is a good idea to hire an air conditioning contractor for a seasonal tune-up. Preventative maintenance helps to extend the life of your HVAC system as well as cut down on unexpected breakdowns and repair costs.

Air Conditioner Winter Prices

Generally in the summer season retailers hike their air conditioner prices because of the increased demand. This is why buying air conditioners in the off-season will be cheaper. People do not opt for air conditioners in the winter season since it is already so cold, but you can get the best deals in this time.

Retailers lower down the prices of air conditioners in the winter to get rid of the old stock and make room for new orders. You will get quality air conditioners at reduced prices.

The demand for air conditioners goes down in the winter season and so does the price. Retailers have ‘special sale’ offers for customers, offering the latest air conditioner brands at reasonable prices. You can save your money by shopping for air conditioners at a cheaper rate in the winter.

Big box stores like Best Buy and Target are a good go-to. You might also be surprised how many AC units you can get online, like this Midea unit we love on Amazon.


There you have it. By following these steps to cover window AC in winter, you should be able to properly store your unit through the colder months, so it works well in the warm summer months when you need it most.

Don't forget to occasionally check on the unit and clean it as needed. A little work here and there will save you a major headache and cost in the long run.