Fun with Ventilation
There has been a flurry of activity out at the house recently. We installed two new Panasonic bath exhaust fans and a whole house Panasonic Energy Recovery Ventilator (ERV), all three of which were generously donated by Panasonic. Bath and kitchen exhaust fans are essential in ensuring good indoor air quality by removing pollutants from the home. They are also Energy Star certified, so they will be both energy efficient and quiet.
Bath exhaust fans rarely provide the amount of airflow that they are rated for due to poor duct installation. Installing small exhaust ducts with lots of elbows and long runs seriously restricts the airflow, but they are very common mistakes. Instead, the duct should provide a short and direct route outside of the house, and the ductwork should be pulled tight. As though they were trying to prove my point, I had to ask the electricians to rotate both of the bath exhaust fans because the initial installation positioned the exhaust port much too close to the ceiling joist, leaving no place for the duct to connect and run to the exterior. Once they were corrected and facing the right way, we used a combination of hard metal piping and flex duct (see photo below). We’ll do airflow testing at the final to verify the exhaust fans are providing the rated performance.