Bathroom exhaust fans aren't just around to remove icky smells from the room although they do work great for that purpose. The exhaust fan keeps your home well-ventilated, improves air quality, helps to remove moisture from the bathroom, and prevents mold growth—which is definitely something you don't want in your home. So when your exhaust fan isn't operating at its peak, then you're putting your home at risk for nasty smells, horrible mold, and ventilation problems that will only get worse as time goes on.
Troubleshooting Common Exhaust Fan Problems
Is the exhaust fan in your bathroom working optimally? There's an easy way to test your fan for functionality. Take a single square of toilet paper and turn the fan on. Hold the toilet paper right up against the fan, and remove your hand. If the fan holds the paper on its own, then it's working well. If it doesn't, then you need to do some work to get your exhaust fan functioning the right way.
Check for Consistent Air Flow
First, go inspect the exhaust vent. The vent pipe for the fan will go up from the room all the way through to the roof of your home. If you have an attic, go into the attic and visually inspect this exhaust pipe. You may find that an animal has built a nest inside of it, or storm debris from outside has fallen down into the pipe. Clean it out, and you should notice much better airflow in the exhaust fan.
Check for a Direct Route
If there are no obvious clogs in the exhaust pipe, check for other problems that could be affecting your airflow. Is the vent pipe made with flex duct, rather than a smooth-walled duct? Are there lots of bends and twists in the ductwork? Either one of these problems can compromise how well your exhaust fan works. Call a plumber to have the ductwork re-done, and you will notice a huge difference in how your bathroom vent works. The exhaust duct should be less than 20 feet long and have three or fewer elbow bends in it.
Ensure Air Flow Into the Room
Check your bathroom door. If the bathroom vent can't get any air, of course it isn't going to work the right way. There should be plenty of room under the bottom of the bathroom door to allow air to get into the room, so the fan has a source from which to pull the air it needs. If your door has very little or no clearance at the bottom, you will need to shave off the bottom of the door to make some clearance and allow air to flow in underneath it.
Clean the Fan
Over time, dust and grime will get pulled into your bathroom exhaust fan, the same way it pulls in air. Removing this dust and gunk will make your fan operate much more efficiently. First, make sure the fan is turned off. Next, get a vacuum cleaner with a suction hose attachment and clean the fan. The vacuum should draw all the dust and debris away from the blades of the fan, which will make it operate much more efficiently and effectively.
...And if That Doesn't Work
If you try all of these steps correctly and your bathroom exhaust fan still isn't functioning properly, you will need to replace your fan with a newer, perhaps more powerful model. Look for an energy-efficient bathroom exhaust fan, and swap it out for the one that isn't working right. You don't have to remove the entire vent assembly—just the motor of the vent itself. After you make sure the vent is turned off, remove the vent cover and then take out the motor assembly in one whole piece. You'll have to unplug the motor to remove it, which can be easily done with a screwdriver. Once the screws are loosened and removed, turn the motor housing clockwise and pull down.
You can find a replacement motor at any home improvement store. Take the old assembly with you to be sure you get a new assembly in a size that will match up to your existing exhaust fan. Remember to reconnect the wires and securely screw the motor assembly into place before you put the vent cover back on. Consult with a plumber to make sure the ductwork is securely attached to the vent fan. Once this is done, you can start using your new ceiling fan.