Locate a stud in the wall by using a stud finder or tapping the wall with a hammer.
Measure the dimensions of the heater box and cut a hole in the wall beside the stud, using a drywall saw.
Run the wiring cable from the hole in the wall, along the stud, to the ceiling, then to the circuit panel in your home.
Remove a knockout from the heater box and put a 1/2-inch cable clamp in the hole.
Remove 10 inches of the outer casing from the cable. Pull the wires through the clamp into the heater box until a half inch of sheathing is in the box.
Place the heater box in the hole and screw it to the stud in the wall.
Remove a half inch of insulation from the end of each wire using wire strippers.
Connect the black and white wires to the heater wires according the manufacturer's instructions. Connect the ground wire to the heater's green ground wire. Tug on the wires to make sure the connections are tightly in place.
Install the heater into the box and screw it into place with the screws provided. Then secure the grill over the heater.
Turn off the power to the house at the main disconnect box.
Pull the wire through a knockout hole in the circuit box of your home. Install a new breaker or fuse in the circuit panel and connect the wires.
Close the circuit box and turn on the power to your house at the main disconnect box.
Turn on your wall heater and test its operation.