How to Connect a Humidistat to a Fan

Turn off the circuit for the living area in your home where the humidistat will be located.

Attach the outlet box for the humidistat to a rafter that is near the attic fan with screws using the power drill. Make sure the outlet box is not in the air stream of the attic fan.

Measure the distance from the outlet box to the attic fan junction box with the tape measure. Add about 12 inches to this measurement. Measure a two-wire electrical cable with a ground wire to this length. Cut the wire with the wire cutters.

Access the thermostat that is in the junction box for the attic fan. Attach one end of the two-wire electrical cable to the screw terminals in the thermostat with the Phillips screwdriver.

Attach the bare ground wire to the green ground screw in the junction box.

Loosen the lock screw that is securing the mounting plate to the humidistat with the screwdriver. Insert the end of the two-wire electrical cable into the outlet box.

Attach the bare ground wire to the green ground screw. Secure the wires from the fan thermostat to the screw terminals on the switch for the humidistat.

Push the wires into the outlet box and secure the mounting plate by tightening the screws. Turn on the circuit for your humidistat at the circuit panel.