While we all know that an old door or ill-fitting window can create a draft and allow cold air to waft into your home, you may not realize there are other sources of heat loss. When it's cold outside, remember that a door mail slot or a doggy door can act like a small window left open to the outdoor elements. Take the time to make sure they are completely shut. Even using an old wool blanket to cover the slot or door is enough to make a significant insulating difference.
ANDREWS MCMEEL SYNDICATION