Bathroom exhaust fans serve to move moisture and odors from the bathroom to the outside. Like dryer vent lines, they move air only one way, from inside to outside—their function is not to recirculate air, as your home's ductwork does. In short, they do not form part of the air duct system, which moves heated and cooled air from the furnace and air conditioner into your living space.
Why are bathroom exhaust fans not cleaned along with the air ducts?
Customers often conflate air ducts and bathroom exhaust fans, both of which are sometimes loosely referred to as "vents," and, understandably in that context, they expect the two will be cleaned together. In fact bathroom exhaust vents are not typically included in an air duct cleaning service, as these are two completely different systems, and, more relevantly, bathroom exhaust vents rarely require professional cleaning.
Why? Because unlike dryer vents, which exhaust lint as a byproduct of the drying process in addition to moisture, and air ducts, which serve to circulate air throughout the HVAC system and into the living space, bathroom vents move only moisture. For this reason, they rarely become clogged, and the light buildup they do accumulate simply does not rise to the level of what a professional duct or vent cleaning is intended to remove.
Do bathroom exhaust fans need to be cleaned?
As we all know, however, they can become visibly dirty, as moist household dust sticks to the vent cover and to the fan blades just behind it. It's a good idea to clean these components periodically to reduce the overall amount of dust in your home and to keep the fan motor in good working order. This superficial buildup can be removed fairly easily. To clean the vent cover and fan, a household vacuum and damp cloth will usually suffice. The vent cover, typically plastic, can be lifted off easily. There may be clamps on the side you'll need to gently push inward. Once removed, you can vacuum the cover with a standard household vacuum attachment, or wipe it clean with a damp cloth. If the dirt is particularly sticky or stubborn, the vent cover can be immersed in soapy water. Behind the vent cover lies the fan, the blades of which over time accumulate the same mix of household dust, minor lint, and moisture. This also can be cleaned with a vacuum attachment or damp cloth (cut the electricity before doing so). Ensure the vent cover is thoroughly dry before replacing.
Does a bathroom exhaust fan ever need professional cleaning?
There are cases, however infrequent, when a bathroom fan exhaust requires more than just a wipe-down or light vacuum. On the few occasions when our technicians have been summoned to clean a bathroom vent exhaust, it's to clear a blockage caused by animal nesting. The warm air and narrow passage would seem quite attractive to a prospective home-builder of the small furry or feathered variety. Normally these critters are kept out by screening over the vent, or a damper under the hood. If these mechanisms are compromised, however, nesting animals (often squirrels) will quickly find their way inside, carrying with them their sticks and leaves and other home-building debris, potentially creating a mammoth clog. A blocked exhaust would prevent the escape of moisture and odors from the bathroom and risk overworking or burning out the fan motor.
What is the process for cleaning a clogged bathroom exhaust vent?
The remedy for these clogs is the same technique that breaks up lint clogs and the occasional nest inside a dryer vent line. Our technicians' tool of choice is a spinning, reverse-blowing skipper ball. How does it work? From the outside vent cover, the tool is fed through the vent on an air line, past the obstruction. Once engaged, the tool is then pulled back toward the technician, as its reverse nozzles blast out air, and the debris along with it. The process is repeated until no further debris is expelled.
With all that said, absent a clog, if you don't have the time or inclination to clean your own bathroom exhaust fans, you can usually opt to add this on to your service for a small additional charge—because, after all, some of us prefer to spend a bit more money and save ourselves the time and trouble.
Many thanks to our technicians Ben S and Roy S for lending their expertise to this article.