It probably won’t surprise you to hear that fans are a huge part of your HVAC system. They’re what push the air around your home in the ducts, and that’s a big deal. So when something goes wrong with the fans, it can be a real problem. We’ll go over some common complaints we’ve addressed in the past, talk about preventative maintenance, and help you get a clear picture of what fans do in your HVAC system. If you’re having problems with your HVAC or exhaust fans, read this article and then give us a call—
no headaches and, like always, no surprises.
HVAC Fans and You
Fans are a huge part of HVAC systems. They come in two forms, basically. Blowers push hot or cold air through your ducts and around the house, heating or cooling as they do so. These fans are important and if they stop working, your HVAC system is in trouble. Vent fans, like the ones that work in your bathroom or kitchen, are designed to pull smoke or steam out of the house. These can be bad if allowed to stay inside—it’s the fan’s job to get them out.
Both types of fans have an important relationship with your system’s ductwork. Sizing a new fan to the ducts, and vice versa, is essential. If this isn’t done right the fan will work too hard, making more noise and ultimately dying a lot faster than it should. If your fan goes out, it’s often a sign of greater HVAC issues at play. That’s why it’s important to get fan issues checked out immediately. Don’t wait—a quick fix today might be a big fix tomorrow.
Common Fan Issues
We get a common complaint involving noisy bathroom fans and other kinds of exhaust fans (like vent hoods over a stovetop). Quieting a noisy fan is tricky—
if the noise is getting worse, we may be able to fix the fan, but often we’ll end up replacing it. On the other hand, if the noise has always been exactly as bothersome as it is now, you may just have a noisy fan. Some fans are simply not designed with noise level in mind and can be very annoying to listen to for more than a few minutes. The solution is the same, though: replace the noisy fan with a quieter model. This may involve some ductwork to ensure the fan isn’t working too hard, a common cause of fan noise.
One uncommon cause of fan noise is when the blades strike the sides of the enclosure, resulting in a noise much more alarming than just annoying. If that’s occurring in your fan—and
you’ll know because of the scraping sounds—
you need immediate attention. Turn off the fan and call a contractor!
The fans in your HVAC system proper are a little different than the exhaust fan in your bathroom, but they have basically the same job: move air through the ducts, in this case into and around your house. They can be noisy, too, and odd furnace or AC noises should be addressed.
But by far, most of our calls relating to HVAC fans (or blowers, as they’re also known) fall into one of two camps. The first is that
But by far, most of our calls relating to HVAC fans (or blowers, as they’re also known) fall into one of two camps. The first is that the blower won’t turn on.
This can be caused by a number of things, from bad capacitors and belts to a bad blower motor in general. If your system turns on but the fan never does, the problem is something you’ll need to have a pro take a look at.
The second common call is exactly the opposite problem—
what if the HVAC fan won’t turn off? When your HVAC blower never stops running, your first stop is the thermostat. Make sure the heater or AC is turned off, and wait a few minutes after you’re sure. If the fan continues to run, there could be a problem in the thermostat or the wiring. There could also be a problem with the relay/limit switch in the blower—
which is usually what’s wrong when this problem occurs. It’s a pretty straightforward fix for a contractor, as is thermostat replacement, so there’s no reason to put off having it done. We’ve had clients who flipped their circuit breaker when they got tired of the noise—
we wish they’d just called us sooner.
There’s not a lot you can do to keep your fans in good shape, although having yours occasionally serviced is a good idea. Blower cleaning is a part of any standard tune up, and we always pay blowers and other fans good attention when we’re working. As a homeowner, be sure to inspect vent fans in bathrooms for mold or mildew—
that can be a sign of an unhealthy system! Just take a look up once in awhile; if you see something on the cover of the fan, make sure to get it checked out at your next HVAC checkup or sooner, depending on how bad it appears to be.
Really, the best thing you can do is pay attention. With fans especially, this means listening attentively every once in awhile. You use these systems every day, and you know what they should sound like. If something is scraping or rattling, or just whining at a higher pitch than you’re used to, get it checked out. You don’t have to look for problems that aren’t there, but you are your fans’ best ally when they’re trying to tell you something. And the best thing you can do (after checking the thermostat) is to give us a call. We’ll straighten out whatever the problem is
and make your fans purr like they should—
instead of scraping and whining.