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dlh3354
Noisey floor vent

I had a furnace installed that is a bit to large for the house. I did not realize this until after the fact and the installer did not tell me this ahead before installing it. It appears to work fine but the air flow in the existing vents makes noise. I am trying to sell my home and do not want to go the expense of another install so is there something that I can wrap them in to help muffle the sound. It is not terrible so I think that would be the answer. Also, will the furnace size be an issue for home inspector? Good grief, will it ever end?

Sten
Re: Noisey floor vent

Furnaces blower motors are sized in tonnage or the amount of air that it will move, if your furnace is oversized you may be pushing to much air which will cause a sort of whistling noise. I doubt that changing the blower motor to one that pushes less air would be wise as you would have problems with the high limit or furnace overheating and shutting down. If you are hearing a banging noise it is more than likely that the Duct work or Plenums lack crossbracing (the plenum or duct is bent diagonally making it more rigid) so when the furnace turns on it won't push out the sides of the Supply Plenum or suck in the Sides on the Return Plenum making a popping noise. Short of replacing the plenums a 1 x 1/4 x L piece of steel could be screwed diagonally to the plenum to make it more rigid. If the Contractor sized the Furnace to fit your house and it's oversized and you knew nothing of it he may be liable for a replacement. Good Luck!!! :)

canuk
Re: Noisey floor vent

It's not uncommon to have velocity noise when new efficient furnaces are installed ..... usually the HVAC company is economizing the install for a variety of reasons.

As already mentioned there can also be noise from the ducting and trunks expanding and contracting with higher velocity air moving through them.

However, depending on the furnace there may be a multi-speed or variable speed blower motor installed which allows a slower speed without really any issues with tripping the high limit. Lowering the blower motor speed will reduce the velocity noise .... but ..... this also impacts the balancing of the system's air flow.

Sten
Re: Noisey floor vent

If you are getting velocity noise through supplies your Furnace is pushing to much air (not sized right) or your supplies are undersized (not sized right). I have only found a couple of systems like this and it wasn't because of a high efficiency unit, Bottom line, if it is sized correctly you should hear next to nothing. If the ductwork has crossbracing you should not get popping noises or, expansion and contracting. If you lower the blower motor speed you will not get the required CFMs. Economizing a system usually ends up with a complaint and is done to save the Contractor $$$. "Do It Right Do It Once" Good Luck!!! :)

Bob Gabrilson
Re: Noisey floor vent
dlh3354 wrote:

I had a furnace installed that is a bit to large for the house. I did not realize this until after the fact and the installer did not tell me this ahead before installing it. It appears to work fine but the air flow in the existing vents makes noise. I am trying to sell my home and do not want to go the expense of another install so is there something that I can wrap them in to help muffle the sound. It is not terrible so I think that would be the answer. Also, will the furnace size be an issue for home inspector? Good grief, will it ever end?

You don't say where the furnace is located but if it's in the basement you could relieve some of the air noise (pressure) there. The newer furnaces have pretty strong blowers, especially oversized (larger) furnaces.

Sten
Re: Noisey floor vent

Good thinking, he could always put a run into the cellar, and also a return. ;)

rdesigns
Re: Noisey floor vent

Slowing the fan down as Canuk suggested is the first and easiest thing to try. The installer would likely do this, no charge, since he admitted to over-sizing the furnace.

If the noise seems to be caused as the air rushes thru the vents of the registers, you might also try installing new registers that are rated for higher velocity and less noise. Manufacturers of registers supply specifications on every register they make to show how they perform at given velocities and CFM's. They are also rated for noise levels.

Bob Gabrilson
Re: Noisey floor vent
Sten wrote:

Good thinking, he could always put a run into the cellar, and also a return. ;)

Even a blind hog finds a nut sometimes. LOL

Sten
Re: Noisey floor vent
Bob Gabrilson wrote:

Even a blind hog finds a nut sometimes. LOL

Bob,
On your TOH control panel there is a link that will let you receive private messages, you should activate it.

Bob Gabrilson
Re: Noisey floor vent
Sten wrote:

Bob,
On your TOH control panel there is a link that will let you receive private messages, you should activate it.

Thank you. I'll look for that. I appreciate the advise.

Ander
Re: [Noisy] floor vent

Hi,

We're having this problem too since we had our old furnace replaced by a high-efficiency one. The installer said our fan is on its lowest setting, but it's still difficult to hold a conversation in our living room because of the hissing floor vents.

There have been a couple of references here to noise being caused because the installer "economized the install". What does this mean? Did he omit some kind of equipment that would've given us more control over the airflow?

Thanks for your help, as this is really annoying! Cheers, Ander

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