Many houses built today have the laundry room in a centralized location.This means instead of the dryer vent being short exiting the wall it is vented through the roof.While this is convenient it also mean extra maintenance. If your dryer is not drying your clothes in a timely manner or there is excessive heat in the laundry room this may be a sign that the dryer vent needs cleaning.Many chimney sweep companies also clean dryer vents.Before you purchase a new clothes dryer make sure the problem is not the dryer vent. For more information visit my website http://jeffslusser.net