How to Insulate a Window AC Unit For Winter

As the weather shifts, remember to winterize your window air conditioning unit. As homeowners look to reduce energy loss, a recent study from Schneider Electric showed that 36% of Americans don't have the time or knowledge to make a difference in their own home. In this case, a small action can make a big difference in your winter utility bills and overall home energy efficiency.

Not to mention, removing or covering it can prevent damage and ensure optimal performance when you need it again next year during the hot summer months. 

Follow these steps, and learn how to add proper insulation to your window unit. 

If You Can Remove the Air Conditioner Unit:

Can you safely remove your window unit? It's best if you do:

• Why: It's not a year-round necessity, and removing it during winter will protect it from the damaging effects of the winter elements. By keeping the window closed, you'll create a tight seal between the inside and outside reducing air leakage and heat loss. Good seals promote good energy efficiency. By closing the entire window, you'll see energy savings (and that translates to lower energy bills during the winter months).
• What to Do: Carefully uninstall the window unit, clean the dirty filters, dust the exterior-facing panels, and store it in a dry and sheltered place.

If You Can't Remove Your Air Conditioner Unit:

1. Unplug the Unit

• Keep window air conditioners unplugged during the winter. If you need to keep it plugged in, store the remote control to prevent accidentally activating it during winter.
• Unplugging it is more energy efficient.

2. Seal Gaps Around the Window Frame

• Use weatherstripping, polyurethane foam tape, rope caulk, black foam weatherseal, or another flexible foam insulation material to seal gaps between the window unit, the window sash, and the window frame. Any openings can allow cold air leaks to enter your home and warm air to escape.
• If your window AC model has accordion-style panels, insulate the accordion flaps with foam insulation panels. While the panels are useful, they're not a great barrier against air leaks any time of year.
• Adhesive insulation products are ideal. Don't use spray foam insulation or a bead of caulk around a window unit. That said, if your window frame itself needs additional sealing, pull out your caulk gun and take care of business.

3. Cover the Outside of the Window Unit

• Use an outdoor, weatherproof cover to protect the AC unit body from snow, ice, and debris. Not expecting extreme weather conditions? You can also use a breathable fabric layer as additional insulation.
• Make sure that it's securely fastened but allows for ventilation.

4. Use an Interior Cover

• Add an interior cover to provide an additional layer of insulation and protection.
• You can purchase a cover, use foam panels, or use a heavy-duty trash bag secured with duct tape to cover the inside of the AC unit.

5. Elevate the Unit Slightly

• Elevating a window air conditioner unit helps prevent damage from snow accumulation.
• Place a wooden or plastic block under the unit to lift it slightly off the window sill.

Always Check Window Security

When installing or removing a window AC, double-check that your window locks are still working. An unsecured window can make your home more vulnerable.

Some homeowners use smart devices for their windows like the new Avia Smart Sash Fastener. And, there's always the option of contracting with a local security service for added peace of mind.

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FAQ

Can I use spray foam around a window AC?

Yes, but only around the frame — not the unit itself. Spray foam can seal big gaps and stop air leaks, but make sure it doesn’t block airflow or damage the housing.

How can I spot energy loss around my window?

There will be signs! We like the "candle test." Light a candle and carry it along the edges of your windows and doors. If the flame flickers or blows out, you've found a draft.

Jeramy Sibley, the President of Glass Doctor, a Neighborly company also references the "paper test." To do this, "close a piece of paper in the door or window jamb; if it slides out easily, there's a gap."

By taking these steps, you can safeguard your window AC unit from winter weather, reduce energy costs, and extend its lifespan. Always refer to the manufacturer's guidelines for specific recommendations related to your AC unit.