When you run your dryer, do you ever wonder what happens to all that moisture that is in your clothes? You might not, but ensuring that it gets vented out of your home is very important. Why is that? It is because the average load of laundry contains about a gallon of water, and if it is released into the air inside your home, it could cause all kinds of problems when it condensates, such as water damage and mold.
A proper dryer exhaust needs to be vented to the outside, 3 feet or more from anything that might take in air, such as, doors or windows, and at least 10 feet from an air conditioner.
The duct should also be horizontal and with as few bends as possible, since a buildup of lint and dust inside of the duct could lessen the effectiveness of your dryer, or even worse, cause a fire.