How to Winterize a Sliding Door With a Dog Door

Sliding doors with dog flaps can increase heat loss.
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Up to a third of your home's heat loss during the winter occurs through windows and doors, according to the National Resources Defense Council, and a dog door only increases that percentage. You want to give your canine pal easy access to the backyard, but you also want to avoid high energy bills. Winterizing a sliding door and dog flap will allow your family to enjoy the best of both worlds.

Clean Contact Points

Use a mild cleaning agent, or a solution of one cup white vinegar and one gallon hot water, to clean the sliding door tracks and frame, as well as the dog flap and all contact points. Even the smallest flecks of dirt and dust can reduce the air-tightness of a dog door. Dirt could disguise rips or tears that could reduce the flap's effectiveness.

Detect Leaks

Run your fingers along the frame of your sliding door as well as the edges of the dog door. When you feel a draft or change in air temperature, mark the spot with a strip of painter's tape. You also can light a candle and move it along the frame. When the flame flickers or changes direction, there is probably a leak. To ensure accuracy, turn off the air conditioner or furnace for the duration of your inspection.

Fill Gaps

Caulk any gaps between the sliding door and its frame, or between the frame and the house. Caulking is the most cost-effective way to winterize a door, especially when you find only small gaps. You can use caulk to seal cracks between the frame of the dog door and the glass. Push excess caulk into the gaps with a putty knife or other thin tool, then wait at least 36 hours before allowing your dogs access to the door. Your furry friends might attempt to lick wet caulk, which could be toxic.

Replace Weather Stripping

Weather stripping will not last forever. Longevity varies between different products, but if the strips look too thin or frayed, it is best to replace them before winter arrives. Check with the manufacturer of your sliding door and dog door to determine whether you need a specific brand of weather stripping. Otherwise, a generic brand should suffice.

Check Alignment

When a sliding door sits crooked in the track, or when a dog flap no longer hangs straight across the hole, hot air will escape your home. If you have just moved into a new house, for example, check all sliding doors to make sure they have been properly installed. Verify that the edges and corners of all dog doors are straight and uniform.