Page 4 of Bath/Ventilation Fans & Heating Products by NuTone

nutone ventilation fans ­ installation guide nutone ventilation fans ­ sizing guide proper installation makes all the difference easy steps for choosing and sizing the right ventilation fan for your home determine which rooms could use ventilation and how much is needed spot ventilation is used in localized areas to remove moisture odor and airborne pollutants quickly most commonly used in the bath or powder room spot ventilation can also be used in a laundry room exercise area closet or bedroom wherever air should be changed frequently decorative and recessed models can be ideal solutions for these situations according to the home ventilating institute air changes per hour ach for comfortable and healthy living should be as follows bathrooms 8 changes kitchens 15 changes living/bedrooms 6 changes nutone bath fans utility fans and high capacity fans meet these needs calculate the air movement necessary for proper ventilation air movement is measured in cubic feet per minute cfm to determine cfm requirements first determine the size of your room measure and multiply the length width and ceiling height of your room to determine cubic footage then use the multiplication factor of .13 and round up to the next ten see the three examples that follow example 3 for a bathroom with a vaulted ceiling use the average ceiling height at the wall and the peak 8 wide x 12 long x 8 at wall 12 at peak 2 10 average height x .13 125 select a fans with at least 130 cfm account for long duct runs and ductwork that turns before it reaches the exterior vent when airflow is restricted in any way it slows down just as a car must slow down for a sharp corner air decelerates when going through a turn in a duct run whenever possible create a straight duct run with large radius turns if they re necessary at all rigid ductwork is optimal because airflow restriction is minimized flexible tubing may be convenient to install but resistance is created as air is moved over the spiral metal frame of the tubing with long duct runs or ducts with multiple turns the fan works harder noise increases and fan performance cfm is compromised select a fan model with an even greater cfm ratio to compensate 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 performance a good ventilation fan is the product of research testing and listening to the needs of consumers at nutone we build these desires into ventilation products that provide the best mix of power sound and quality for every budget 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 example 1 bathroom with 8 ceiling 7 wide x 9 long x 8 high x .13 66 select a bath fan with at least 70 cfm example 2 bathroom with 9 ceiling 10 wide x 9 long x 9 high x .13 105 select a bath fan with at least 110 cfm 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 ducting overcomes most performance-related installation issues nutone s qtx series fans deliver high performance in virtually any real-world installation they are engineered with a 6 duct connector for peak air movement and extremely quiet operation even when the duct run is not short and straight 6 7

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