Bathroom exhaust fans are installed in the ceiling and vented to the outside, usually through the attic via a roof exhaust duct. This process involves installing and wiring the fan and connecting it to duct work that allows the moist air to escape.
The preferred place for the fan is between the shower and the toilet. A spade bit is used to make a reference mark, and then the installer goes into the attic space above the hole and removes any insulation in the way. Then, the vent housing and the ceiling hole are measured and the latter cut to size. The power to the bathroom should then be turned off.
Back up in the attic, a 90-degree, 4-inch-wide duct elbow is attached to the outlet port on the vent housing. The cable connector is installed, the fan is installed in the hole, the flexible duct work is attached to the elbow joint and then the electrical cable is attached.
An exhaust hole is drilled on the side of the attic wall, and the other end of the duct work is connected to a wall cap and taped into place. The wall cap keeps birds, insects and other animals from crawling into the duct work.
Back in the bathroom, the electrical wiring is attached to the wiring box found under the blower fan. The fan is reassembled, the plastic grill is installed, and the power is turned back on for testing.