Remove Existing Fixture
Turn off the power to the room you will be working in at the breaker or fuse box.
Remove existing light fixture. Note how the fixture is wired. In some older houses it is difficult to know which is the hot and which is the neutral wire. Black is usually hot, white is neutral, and green is ground.
Inspect the mounting of the previous fixture. If a junction box was used, was it mounted to a ceiling joist or is a 2 x 4 header screwed into the joists? If not, a header (an 18" 2 x 4) must be installed, or a brace box can be used.
If you have attic access, a 2 x 4 header can be screwed to the joists to support your junction box. In you do not have attic access, use a brace box.
Installing 2x4 Header
Screw the junction box to your header.
Position the header, centering the junction box in the hole in the ceiling. Make sure the junction box is flush with the ceiling surface.
Screw the header to the ceiling joists.
Installing a Brace Box
Slide the bar for the brace box through the hole in the ceiling.
Position the brace box. The ends should rest on the plaster ceiling from above. Center it in the hole.
Using an adjustable wrench, rotate the bar so the brace expands. Extend the brace until the teeth on the ends bite into the joists.
Attach the junction box using the U-bolt that came with the brace. Center the box in the ceiling hole.
Wiring and Installation
Punch out one hole on your junction box.
Install a wire clamp in the hole you knocked out.
Run house wiring into the junction box through the wire clamp. Tighten the clamp.
Install your ceiling fan. Carefully follow the instructions included with your ceiling fan. Instructions can vary from model to model.