To winterize your doors, you need figure out ways to make sure your door isn't letting any cold air into the house or warm air out. Simple tips for winterizing your doors includes checking alignment, adding a draft snake and even using caulk and weather-stripping to plug up any leaks your doors may have. Here are those tips and an explanation for each to help you winterize your doors.
A crooked door can create a lot of open spaces for air to get in and be released from your home. Make sure the hinges are on right, that the door was installed properly, and that it closes well. If your door is out of alignment, you have to find the problem and fix it to set it back in place so that it's properly aligned, otherwise that will compromise the warmth of your home.
To cover up the gap between the bottom of your door and the floor so you don't get a draft coming into the home, add a draft snake on the inside of your door for some extra protection. You can easily make your own draft snake out of scrap fabric, towels, recycled clothes and more, so it can be a fun addition to your door. While you may already have a bristle sweep for your door bottoms, a draft snake can add another layer of protection for your home from the bad weather outside.
Caulk cracks and holes, and weather-strip the sides and the top of your door so heat can't escape and cold air can't get in. Cracks and holes need to be closed with caulk to prevent warm air leakage and to eliminate cold air entry points. Weather-stripping also works to block entry points for cold air to come into your home.