How to Reduce Noise from an HVAC System

LESLIE: Brent, you’ve got The Money Pit. How can we help you today?

BRENT: I’m trying to figure out a way I can quiet the noise – lower the noise level – on our new home that we built. Our home is basically an open-concept: high ceilings with a lot of wood, tile. Well, I’m wondering – no window coverings. But when our – I’ve heard that you can change out your pulleys, like maybe on your fan blower, to lower the noise level. Is that possible doing or not? Have you ever heard of that before?

TOM: So, the noise that you’re trying to reduce is the sound of airflow from your HVAC system?

BRENT: Yep. We have a heat-pump system and like I said, our house has mainly a lot of wood: our ceiling is wood, we have a lot of windows. And when it kicks in, it just roars, you know what I mean?

TOM: You get a whistling sound when the blowers come on?

BRENT: No, just the actual airflow that you hear. And just trying to find a way to absorb that noise or maybe just – I’ve heard that, like you say, you can slow that – maybe the flow of the air down?

TOM: Well, depending on the system, you actually can adjust the fan speed.

BRENT: Right.

TOM: But there may be a point of diminishing returns if you reduce the fan speed: you may not get the air moving throughout the house where you need it. Unfortunately, this is an installation issue when it comes to how the HVAC system was designed.

Now, also, if you have metal ducts, you could be getting some vibration in those ducts and those ducts could be dampened or reinforced with a few modifications. For example, if we get a duct that makes a lot of noise, sometimes you can take a piece – an additional piece – of metal and attach it to the top of the duct in a diagonal fashion and that will reinforce it and take some of the flex out of the duct and reduce the vibration noise.

So, there are a couple of small tweaks like that that you could try. But what I might recommend you do is the next time you have your heating system serviced, that you spend some time and maybe let the company know in advance that you want to speak with one of their technicians about reducing noise and see if there’s anything else that could be done. You also, for example, could insulate some ducts that might be accessible and that might quiet some of the noise, as well.

So this is going to be a series of small steps with small improvements, not big steps with big improvements. OK, Brent?

BRENT: OK. Thank you.

TOM: You’re welcome. Thanks so much for calling us at 888-MONEY-PIT.