If your home does not have an extractor fan in the bathroom, you can save money by installing one yourself instead of paying a contractor. Bathroom fans ventilate the room to eliminate moisture left behind after using the shower or sink. You may need an electrician to add the necessary wiring if your bathroom is not already equipped with an overhead light and wall switch.
Turn off the circuit breaker switch that controls power to the bathroom.
Hold the installation template up to the ceiling or wall where you plan to install the fan. Check the area with a stud finder to make sure there are ceiling joists on both sides of the fan. If you cannot find a suitable location near two joists, measure and cut a 5 x 10 cm (2 x 4 inch) board to match the width of the fan. Use wood screws to attach this support piece to the nearest ceiling joist.
Trace around the template, making sure to mark the locations of the mounting screws. Use a jigsaw to cut a hole according to your outline.
Attach the fan's electrical wires to the home's wiring with plastic wire connectors. Follow the wiring diagram in the manufacturer's installation guide for specific instructions relating to your fan's make and model.
Use a duct clamp to connect the exhaust duct to the back of the fan. If you are installing a bathroom fan with a light, you may need to clear out a certain amount of space between the back of the light and the ceiling insulation. The owner's manual or installation guide should list the proper distance for your fan.
Secure the fan assembly to the ceiling joists with the mounting screws included in your installation hardware package. Turn the circuit breaker switch back on to restore power to the bathroom.
Follow the wiring diagram in your installation guide to connect the switch wires to the fan assembly. Drop the open ends of the wires into the wall above the switch plate. Remove the existing switch plate and switch so you can grab the loose wires. Connect the wires to the switch and reinstall the switch plate.
Place the open end of the exhaust duct outside the home so the redirected moisture does not ruin the roof or walls. If your home has an attic, attach an extension duct and insert the open end into a soffit vent.
You can install a double switch to control the fan and overhead light separately.