I've recently moved into a rehabbed industrial space that is now a condo. The HVAC system seems very loud, and I'm just wondering if this is something a professional needs to look at or if there is something I can adjust or DIY something to lessen the noise. I can hear the system "click on", which is fairly unobtrusive, but about 30 seconds later (maybe when the blower actually kicks in) the sound changes and it's loud enough that it interferes with convesation, TV watching, and I've actually been awoken from sleep. The majority of the ductwork is exposed. It makes sense to me that I'd be hearing more noise that I'm used to in a traditional home, but this just seems excessive.

I know very little about heating systems, so I'm not sure what information is relevant. Just to give you an idea of the setup:

The home is very long (90ft?), narrow (maybe 20ft?) and tall (30ft) with the main living space on one floor, an open central area, and a lofted bedroom on either end of the building. The furnace is located roughly midway in a utility area, and from it there is a long run of duct that goes to either end of the building and then up to one of the bedrooms. The furnace is a Trane, model XR90. I haven't lived here long enough to use the AC, and it's not easily accessed, so I'm going to omit the info for it unless deemed useful by the readers.

If the ducts are metal, sometimes insulating them will help with sound issues, sometimes not.

Many factors come into play with noise values of forced air gas furnaces. I would suggest having a train dealer come in to check the system and let you know if the noise is normal. Most likely he will say that it is for the system and setup that you have. There may be ways to lessen the noise, but it may get costly. Without being able to hear it for myself, it is impossible to say one way or the other. Most likely noise was not taken into account during the install for a industrial space, and now that it is a residential dwelling, you are dealing with industrial system noise. Most of the noise you are hearing is probably coming through the return ductwork or grill. Not a dyi job by any means without knowing if the noise is normal or not. Get a tech in there to give you advice.

Thanks for your opinion on it. I'll note that this whole HVAC system was actually newly installed as part of the change to a residence roughly 5 years ago. Which doesn't necessarily mean they actually took noise into account, but I thought might be worth clarifying.

Quote:

---

Originally Posted by Grady White

If the ducts are metal, sometimes insulating them will help with sound issues, sometimes not.

---

Hmm, the ducts are metal, but I'm not sure if this is a possibility. They are all exposed and supported by cables, and it seems like insulating would add a lot of weight. Not to mention, this is probably going to look pretty darn ugly. :)

Mygirlsdad, is there any way for me to isolate where the noise is mainly coming from? Maybe more importantly, does that help you give me any more ideas if I can narrow it down?

You are also facing what appears to be an open box for a living space. Hard to suppress noise from mechanical and air. May be able to slow the fan speed down and use ceiling fans for distribution. Is the air handler in a separate room? Suggest you read up on noise control and sound transmission loss-STL. May find some ideas there. In my prior working life I did a lot of noise control using octave band analysers.

I agree with both Grady and ma0641. Insulating ductwork may help. Slowing fan speed (as long as it still has enough cfm for the unit to function properly and efficiently) may also help quite a bit. Another thing is if there is return ducting, or just a return grill off the furnace itself. If there is only a return grill at the furnace, you will get a lot of noise there. Also, is your unit a 90+ eff? If so, are there one or two plastic pipes that go outside? If only one, you can get a good amount of noise through the combustion intake port on the furnace, from the draft inducer and actuall flame . Running a combustion air intake pipe outside per manufacturers instructions may help with the noise a bit if this is the case. What brand and model is the furnace? Some are simply more noisy than others.