The first and most important tip for replacing a ceiling fan is to ensure that all electrical power to the fan is shut off. This means going to the main power controls for the home and turning off that breaker switch, effectively cutting off all power to the room in which the fan hangs. Failing to do so could result in serious injuries. If this means the room is dark when replacing a ceiling fan, have another light source handy, such as a flashlight or floodlight. Do not work in the dark, as this can also lead to injury.
Before replacing a ceiling fan, be sure to read any instructions that were included with the new fan unit. The fan may have specific installation directions that can alter the process of replacing a ceiling fan; the person installing the fan should make sure he or she knows which color wires serve which function. While most wires will be color-coded similarly, it is best to check before attempting installation. If possible, the installer should remove the fan blades from the new fan as well as the old fan during the installation process to make handling the units easier. It is also a good idea to remove the light bulbs and bulb covers or shades as well.
When removing the old fan unit, carefully cut the wires. Do not cut them too short, as these wires will need to be reused when replacing a ceiling fan with a new unit. Save the wire nuts, if possible, to reuse those as well. These wire nuts will hold the wires together tightly, forming the electrical connection. If possible, have an assistant stand nearby to take the old unit and hand up the new unit, as the installer will likely have to stand on a ladder or chair to reach the ceiling where the fan will be installed. Hand the old unit down and take the new unit.
Check again to make sure the wires are color coded. If they are not, make a note of which wires should be attached to the wires in the house. If necessary, write the purpose of each wire on a piece of tape and tape the wire, remembering that the ground wire is usually black. Reattach the wires using the wire nuts and make sure the connections are solid. Screw the new unit back into the ceiling; install each screw a few threads, then go around and tighten them so all screws are supporting the unit as the installer tightens. Turn the power back on and check to see if the unit works properly.