Unventilated bathroom moisture can settle down in crevices all over the place and create a favorable environment for growth of mold. You can take care of the mold problem, through use of appropriate chemical cleaners, but there are ways in which you can prevent it.
Bathroom exhaust fans are normally located on the ceiling. They are connected via an air duct, that directs the exhaust gases outside, promoting ventilation. Replacement is not as difficult as the installation, which involves setting up the wiring, as well as setting up the air duct for the exhaust.
Knowing when your fan needs a replacement is easy. When you notice that the low whirring noise of the fan has stopped, there is something wrong. Mostly, it only involves motor replacement. The fan itself need not be replaced, if it's the motor that is not working.
Hardware stores supply fan motors. You can buy one and only replace the old motor. However, if the fan too has a problem, it's best to go for a total replacement.
The first thing to do is to get a replacement for your old fan, which matches its size, power, and dimensions. You can buy one from any hardware store nearby. In case, you have seen that only the fan motor needs replacement, then get a new motor, with the same power ratings as the old one.
Since the motor is the most important driving part of the fan, replacing it is as good as replacing the fan. Only if the fan is broken and making a lot of noise, then replace the entire assembly. The things that you will need are flat headed screwdrivers and Phillips screwdrivers.
Firstly, switch off the electrical power supplied to the fan. Then, use a stool to access the ceiling fan apparatus. A tug at the exhaust fan grill might easily remove it. If there are screws holding the grill, unscrew them to access the fan inside. Sometimes, people need to go for a grill replacement too, if it's broken.
If the fan's intact, all you need to replace is the motor fitted behind it. Remove the old motor, by unscrewing attachment screws and replace it with a new one. In case the fan is broken, you can replace the entire assembly.
With the motor replaced, fix the fan back in the ceiling slot and tighten the screws. Make the electrical connections back again. Check if the fan is working, by switching it on.
Replacement is quite a straightforward job, which anybody could pull off in a few minutes. All you need to do is follow instructions carefully. And this is not at all an 'exhausting' job for you anymore.