The length of your dryer vent hose can have a significant effect on the efficiency of your dryer.
What to Consider
A long dryer vent hose will impede the efficiency of your dryer, make the clothing take longer to dry, and may affect the automatic drying cycles on newer dryers. So when making decisions about where and how to vent a dryer, consider placing a dryer close to an exterior wall to make efficient venting easy.
Also consider carefully the type of vent hose you will use. The flexible, white plastic hoses that were so common in the past have been shown to be a fire hazard as well as inefficient. Although there are flexible metal hoses that can be used, they still encourage lint build up. The most efficient and safest dryer ducts are the rigid, 4” ducts with smooth interiors.
Guidelines to Follow
While it may be important to check local guidelines, there are general guidelines followed by the International Mechanics Code. They state that a straight duct be no longer than 25 feet. In addition, if there is a 45 degree bend, then deduct 2.5 feet from the recommended length, and if there is a 90 degree bend, deduct 5 feet. So, if you have a space that will need two 90 degree bends, then you should have no more than 15’ of dryer duct.