If your clothes dryer vent is too long a house fire may occur. It is always a good idea to shorten the exhaust pipe run and replace it with a rigid metal pipe in order to avoid problems with the appliance and decrease the risk of a house fire.
One hint a problem exists is if it takes longer to dry your clothes than normal. If the exhaust pipe is clogged your clothes dryers built in thermo senor will turn off the heat until the inside of the dryer cools down. Then it will wait a while prior to turning the heat back on.
The end result at some time the interior of the dryer is too hot (shrinking your clothes) and some times it runs without heat (just spinning and not drying).
The real problem is one day when the heat sensor does not shut the dryer down and a house fire occurs when the highly combustible lint is ignited.
