Bathroom vent fans are perhaps the most undervalued — and often under-used — appliance in the home. Its primary job is to get rid of hot, moisture-laden air and replace it with dry air. Damp air in the bathroom doesn't just fog up the mirror, it also carries moisture onto every surface, which collects dust, is hard on paint and other materials and can lead to mold growth. Besides keeping your bathroom dry, a vent fan's secondary job is to get rid of odors as quickly as possible. Enough said.
All of this should be more than sufficient evidence to convince you to use your bathroom vent fans (if you don't already). And to make sure they work as effectively — and quietly — as possible, you need to clean them periodically. This takes just a few minutes, and it offers a few benefits: it ensures maximum airflow, it helps to quiet the fan and reduces wear on the motor, and it makes your fan grill look less disgusting.
Clean Bathroom Vent Fans
The best tool for cleaning a bathroom vent fan is a vacuum cleaner with a soft brush attachment and a crevice tool. You can use a shop vac or a standard indoor vacuum with the proper attachments. You may also need a helper or something else to support the vacuum so you can reach the fan. If you don't have a vacuum, you can use an old paintbrush to clean the fan's crevices, but just be sure to cover the floor to catch falling debris.
- Turn off the power to the vent fan by switching off the correct circuit breaker in your home's service panel (breaker box).
- Remove the fan's grill. Most grills pull down to give you access to spring clips; compress the clips to remove the grill from the housing. Set the grill aside.
- Vacuum inside the housing with the soft brush attachment. Clean all of the interior surfaces of the fan housing and along the outside edges of the housing.
- Use the crevice tool to vacuum inside the fan blade unit. Most vent fans have "squirrel-cage" fans (which look more like hamster wheels); be sure to clean between each pair of blades.
- Wash the grill under water, and dry it thoroughly.
- Reinstall the grill and turn on the circuit breaker.
Is Duct Cleaning Necessary?
Most people never bother to clean the duct between the vent fan and the outdoors, and that's usually not a problem. The only debris that fans pull in is dust. Is there some dust sticking to the inside of your duct? Probably. But it's probably not enough to restrict airflow significantly. By contrast, the ducts for clothes dryers (which are typically the same size as fan ducts) collect loads of lint and tons of moisture, and they can get severely clogged, creating a fire hazard. A dirty fan duct doesn't create a fire hazard.
That said, if you're concerned about your fan duct being dirty, or your fan seems to be working fine but it's not sucking in much air (you can test this by laying a tissue over the fan grill), you should clean the duct. There may be an obstruction, such as a bird's nest, restricting flow.
The problem with cleaning a vent fan duct is getting access to the duct. If you can reach the fan and duct in the attic, the easiest approach is to disconnect the duct from the fan, clean out the duct with a vacuum, then reattach the duct — all from the attic side. If you have a cheap, old flex duct, you might skip the cleaning and simply replace the duct with a rigid metal duct, which moves air better and stays cleaner than a flex duct.
If you don't have attic access, you'll have to remove the fan motor assembly to get into the duct port. In this case, you might need a duct brush to clean the duct adequately, as using a vacuum may prove difficult.
Replacing Bathroom Vent Fans
Bathroom vent fans have a built-in alarm that tells you when it's time to replace them. Okay, that's not completely true. But in reality, fans do let you know when they need replacement by getting louder and louder with age. When a fan gets so noisy that you refuse to turn it on, it's high time to put in a new one. Just make sure you clean the fan first, to rule out the possibility that dust (which can create an imbalance) is the main cause of the noise.
You have two options for bathroom vent fan replacement. One is to hunt down a replacement kit for your fan model. This allows you to replace the fan motor assembly (and often the grill) without having to replace the fan housing, saving you some expense and the trouble of the wiring and duct hookups. It's important to use a kit that is made for your fan model and is high quality, preferably from the same manufacturer.
The other option is complete replacement. This costs a little more and takes more time than a kit replacement, but it allows you to upgrade to a better and/or bigger fan. Builders love to use undersized, low-quality fans in new houses, so it's often worthwhile to install a better fan that will be quieter and move a lot more air than the original builder-grade unit.
Philip Schmidt is author of Install Your Own Solar Panels, The Complete Guide to Treehouses, and 18 other home-related how-to books. A former carpenter, he has been a full-time writer and editor for over two decades, teaching DIYers about houses and everything we do with them.