Electric clothes dryers are not an efficient way to heat your home, but if you're using it anyway, you might as well use that heat to warm and humidify your home in the winter. Not only is your dryer heating air and sending it outside, it is constantly pulling warm air out of your house when it is running. What is coming into your house is cold dry air to replace the air the dryer is expelling. There is also the issue of air coming into your dryer vent when the dryer isn't running. If your outside vent cap doesn't seal well this can make your laundry room very drafty.

Here's what I do every fall to help warm my home, increase humidity and lower drafts in my laundry room.

1) I disconnect my dryer hose from the outside and stuff the hole with plastic grocery bags. These make great insulation, just don't forget to take them out in the spring when you reconnect.
2) I connect a longer dryer hose to my dryer and run it to a lint trap. Try to get the trap as far as possible from the dryer as you want the humid air to dissipate. Depending on your existing setup you may be able to use your existing hose.

Here is my lint trap. Under the sink, next to the washer

Here is the dryer hose running from my dryer and past the washer.

Since I have kids we do a lot of laundry, which in turn results in me never having static electricity issues in the winter as my home is never too dry. These lint traps are pretty common. If you Google "lint trap" you'll find plenty of places selling them. They are filled with water and they catch most of the lint. Warning, If you let the trap run dry you'll end up with a linty home.

I know some people use nylon stockings over the end of the hose instead of a trap but if you didn't clean it often you could damage your dryer or cause a fire. I also have friends who have created larger boxes to capture more lint. Please leave comments or other ideas below.

Warning #1: Only do this in the winter months as you may end up with a mildew problem from excessive humidity and this will work against your air conditioning. We want to expel heat in the summer. Also, the dryer will not be able to dry clothes as fast if it is pulling in excessively humid air. I find this to be a non-issue in the winter because the humid exhaust is quickly evaporated into the relatively dry house air. The further you can get the lint trap from the dryer the better.

Warning #2: Don't do this if you have a natural gas dryer.  You must vent this outside to prevent carbon monoxide buildup in your home.

Warning #3: If you use fabric softeners or home dry clean kits you should probably not do this as you may end up with unhealthy air.

i find that switching over from internal to external venting gives me an excuse to clean lint out of the lines and dryer twice a year. When was the last time you cleaned your vent hose?