In 2005 dryer vents were responsible for about 14,000 house fires.  This is a shame because many could have been prevented with the proper connections, set up and regular cleaning.  Over time the lint from the dryer will build up inside the exhaust duct and can cause a fire.  One indication that the duct is becoming blocked is if your dryer heats up but the clothes inside are still damp when they are done.  This can indicate that the warm, moist air is being restricted and not leaving the dryer as it should.

Most newer homes are set up with dryer safety in mind and easy access to clean, where some older homes the location and access is not ideal and it can be more difficult to clean.  You should clean the exhaust duct on a regular basis.  Disconnect the exhaust duct and stick a shop vacuum in there and reconnect after.

A few things that I look for when I am inspecting dryer vents:

Is the duct connected and go all the way outside?

Some ducts are not connected properly and some just come loose over time. Some ducts vent into a crawlspace or attic.  This will put that moist warm air into places where it can linger and lead to moisture issues and possibly mold.  You want the warm moist air to go OUTSIDE.  There can be backflow protection, but not a screen.  A screen will just catch all the lint and block up faster.

How long and how straight is the duct?

The duct should be as straight and as short as possible.  No longer than 25 feet.  Each 90 degree bend in the pipe reduces the total allowable distance by 5 feet.

What is the duct made of?

The duct should be METAL.  The duct should be smooth on the inside and not have any fasteners or screws going into it that could catch lint and cause a build up.

Lastly, do not connect 2 separate dryers to the same vent like this picture:

If your laundry load really requires 2 separate dryers, please take the time and install another vent to the outside and run 2 separate exhaust ducts.  One for each dryer unit.  Or go to the Laundry Mat. 

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