Page 6 of Ventilation Fans by Broan-NuTone

broan ventilation fans ­ installation guide proper installation makes all the difference tape or caulk around the seam where the fan housing meets the sheetrock on the ceiling if possible use smooth rigid ductwork as large as the exit opening on the body of the fan housing whenever possible ductwork should slope down and away from the fan housing to direct any condensation toward the vent whether rigid or flexduct the turning radius for the duct should be as large as possible keyhole slots and alignment tabs facilitate installation taking the guesswork out of proper mounting elbows turns long ducts and ductwork smaller than the fan s exit outlet will reduce performance use wide aluminum foil or duct tape to join smooth metal ductwork seams do not let flexible ductwork sag as this impedes airflow during installation orient the bath fan outlet in the direction of the home s exit point to minimize duct turns before adding an elbow or bend allow 24 to 36 of straight run from the fan outlet point duct-wrap insulation r-5 or above will help minimize condensation in cold climates especially on long duct runs exit vents should have backdraft flaps to help keep cold air from entering the duct quick guideline for bathrooms up to 100 square feet the hvi recommends ventilation of about 1 cfm per square foot about eight air changes per hour for bathrooms over 100 square feet add up the needs of each fixture to determine the total ventilation rate · toilet 50 cfm · shower 50 cfm · bathtub 50 cfm · jetted tub 100 cfm 6

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