The PlexiDor is the best pet door for cold weather. The doors will function without problems down to -40 degrees (C or F), and work at even lower temperatures. Though, when the quicksilver falls below -40, the door will get frosty and the weather seal may freeze to the frame.
PlexiDor dog doors and cat door are popular in Canada, and have been sealing Canadian weather out for more than 20 years.
In the USA, Alaska is the best selling state per dog household.
Many pet doors are made from plastic and vinyl. The PlexiDor frame is made from aluminum and the panels from K9 Composite. Our frames are three to four times as thick as all other frames on the market. This makes the door sturdy and prevents it from warping in extreme weather. And, the corners of the frames are fitted together with metal fasteners and clips, to make sure the frame stays together.
The K9 Composite is a material formulated specifically for pet door panels. It is an acrylic alloy similar to airplane windshields that withstands both weather and something hitting it with speed. The average PlexiDor panel can be in use for 20 or even 30 years without cracking or warping.
The weather seal is another important difference between the PlexiDor and other pet doors. We use a nylon pile weather seal that is used in doors for malls and movie theaters. It can withstand millions of open-close cycles in cold weather.
If you live in a cold climate, the most important thing to think of is keeping humidity away from the PlexiDor. Avoid mounting the door near a dryer wall-vent – the moisture from the dryer can cover the panels and allow ice to form on the weather seal. Also avoid mounting the door where it will be misted with water. Humidity on the weather seal can cause the panels to freeze to the frame.