DIY: Silent Extractor Fans

An extractor fan helps eliminate mold and mildew in your bathroom by removing moisture.

Silent extractor fans refer to bathroom fans used to remove odor and excess moisture from the room. Some homeowners have the fans installed over a tub or shower. Most fans are designed for ceiling installation and must vent to the exterior. Some local building codes may require a licensed electrician to make the electrical connections.

Things You'll Need

• Extractor fan kit
• Duct pipe
• Aluminum foil duct tape
• Reciprocal saw
• Termination cap
• Mastic
• Sealant
• Electrical wire

Instructions

1. Size the correct fan for the area. This depends on the square footage for the room. Measure the capacity of an extractor fans on the unit’s cubic-feet-per minute (CFM). CFM represents the volume of air removed from the space each minute of operation. Multiply a bathroom by 1.1 to determine the correctly sized fan. Multiply kitchen spaces by two. Select a fan that is at least equal to figure computed. For example, select an extractor fan with a minimum 250 CFM for a 125-square-foot kitchen.

2. Determine the appropriate size ducts for the exhaust system of the fan from the manufacturer’s instructions. The diameter of the duct can range from 3 to 6 inches. Do not deviate from the recommended size or mix sizes.

3. Cut an opening in the ceiling material. Mount the extractor fan housing to a joist in the ceiling according to the instructions. Attach the duct connector to the housing.

4. Plan the vent pipe route to exit through the roof or through an exterior wall. Make sure the vent pipe will be located a minimum of 2 feet from the chimney or flue pipes. Trace around a duct to mark the opening. Hammer a nail through the center and verify the absence of obstacles on the exterior side. Cut the hole in the wall with a reciprocating saw. Make the opening slightly larger than the diameter of the duct. If the fan will vent out through the roof, first cut shingles away with a utility knife to clear an area about 4 1/2 inches in diameter. Then cut a hole through the roof sheathing with a reciprocating saw.

5. Make the duct run as straight and as short as possible. Do not exceed the minimum run recommended by the manufacturer. Turns in the system lessen the operating efficiency of the fan. Apply foil duct tape around all the joints to make them secure and airtight.

6. Install metal roof flashing around roof opening and seal with roofing mastic to ensure a watertight finish. Attach a roof termination cap on the end of the vent pipe. For a hole in the wall, apply sealant around the opening. Secure a vent cap to the pipe. Make sure it has a damper, which prevents insect infiltration and back drafts.

7. Go to the main electrical distribution panel to turn off the electricity to the area. Run the electrical wiring to the housing. Follow the wiring diagram to make the connections, which depend on the control type.

8. Repair and finish any damage to the ceiling. Attach the grill to the housing. Test the fan to ensure it works properly.

References

• Broan; Select-Air Ventilation Fan
• Corner Hardware; Install a Bathroom Fan
• Ask the Builder;Tim Carter