of 4-inch duct, and subtract 5 feet for every 90-degree turn and 2 1/2 feet for every 45-degree turn for dryer vent installation. For example, a dryer with a 90-degree elbow at the exhaust port ...

including the installation and maintenance. A fan that increases the airflow in dryer vent lines. But it's not the same as a standard duct fan. Duct fans feature simple designs that work fine when ...