How Long Can A Dryer Vent Be

Extends to 18 elbow turns 90 within 4 of wall.

The international residential code irc section m1502 clothes dryer exhaust guidelines states that a dryer exhaust duct should not exceed 25 feet from the dryer to the exhaust vent in the wall or roof. Length is only if it s a straight line from the dryer to the exhaust which it rarely ever is. Most dryer too long to dry or poor low heat complaints can be traced back to a bad or poor venting system and sometimes a poorly maintained lint filter do not go outside and put your hand under the vent opening and say it is fine i feel air coming out that is not good enough take your venting apart clean it all out and make sure the vent hood flapper works and that it is not. The maximum length of a straight run of dryer duct is 35 feet with a 5 foot deduction in length for each 90º bend and half that for 45º bends based on using a 4 inch smooth metal vent with no screws protruding into the air flow.

Guidelines to follow while it may be important to check local guidelines there are general guidelines followed by the international mechanics code. However that 25 ft. Male to female connections for use on wall vent duct. 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.

Allows for only 2 clearance between dryer and wall. Let s start with what the irc international residential code says. Elbow turns 90 within 4 of wall.