Bathrooms lacking windows that open must be equipped with exhaust fans.
Bathroom exhaust fans remove humidity and odors. Humid environments allow mold to grow on surfaces, and given enough time, will penetrate the wall coverings to grow within the wall cavities. During cold months when it is impractical to open a window, an exhaust fan serves to remove the warm moist air and replace it with dryer, cooler air from the rest of the house. Modern building codes require an exhaust fan in interior powder rooms and bathrooms not equipped with a window that opens.
Instructions
Placement and Ductwork
1. Use the stud finder to locate a space between two rafters where the fan will be installed; a location near the center of the room is best. Draw the cutout area as described in the manufacturers instructions on the ceiling and cut the drywall away with the jab saw.
2. Place the fan in the opening and fasten it to the rafters with the bottom of the fan just flush with the surface of the ceiling using screws or nails as instructed by the fan manufacturer.
3. Select a location on the side of the house from the attic area for the exhaust duct. Use a hole saw to cut a hole sized 1/4 inch larger than the fan duct exhaust size, through the house sheathing and exterior siding.
4. Install a duct vent with a damper from the outside of the house, through the hole and secure with screws that penetrate the house sheathing at least 1/2 inch. Seal it with exterior latex caulk. Connect the vent to the exhaust fan using semi-flexible or flexible duct pipe. Make as few turns and bends as possible as the straightest run of pipe will be the most efficient. Make connections with metallic duct tape.
Wiring
5. Turn off power to the bathroom lighting circuit and test that it is off with a no-contact voltage tester. Remove the light switch cover and bring the no contact voltage tester probe close to the colored wires. The light should stay off, indicating power is off.
6. Install sheathed cable between the light switch and the electrical box inside the fan housing. Use existing holes between the attic and the wall switch to run the sheathed cable through. Remove eight inches of sheathing from the cable ends with the cable/wire stripper. Insert the cables far enough into the electrical boxes that 1/4 inch of sheathing is inside the box. Strip the ends of the wires using the cable/wire stripper. Remove 3/4 inch of insulation from each wire.
7. Twist the white cable wire together with the white fan wire with a wire nut. Do the same with the black wire and the ground wires; the fan ground wire may be green or there may be a green terminal screw to attach the cable to. The ground wire in the cable is not insulated.
8. Twist the ground wires together in the switch box, leaving a tail to bend into a U shape with the long nose pliers and connect to the green ground terminal screw on the light switch. Remove the wire nut on the two wires in the switch box and twist the new white wire together with them. Replace the wire nut on the two white wires.
9. Turn the switch to the off position. Turn the power on temporarily--the bathroom light should stay off. Use the no-contact voltage tester to determine which black wire has power supplied to it and make note of it. Turn the power off and verify it is off with the no contact .
10. Remove the black wire from the switch terminal that did not have power when the electricity was on. Cut a six-inch piece of black wire and strip both ends. Twist the six-inch piece of wire together with the new black cable wire and the existing black switch wire. Cap with a wire nut. Bend the end of the six inch wire into a U and connect it to the switch terminal.
11. Place the switch back in the box, folding the wires behind it and securing it with the screws. Add the switch plate cover and turn the power on. Turning the switch on will turn on both the fan and the bathroom light.
Tags: black wire, cable wire, voltage tester, ground wire, light switch