How to quiet a Loud Furnace?
 

On Jan 7, 6:06 pm, Speedy Jim wrote:
wrote:
I have a small utility closet whith louvered doors which houses the
hot water heater and the gas forced air furnace. My issue is that this
closet is just off to the side of the living room and the return is
one large vent facing directly into the room. When the furnace kicks
on the sound of the motor, fan, and rushing air through the ducts is
extremly loud and anoying. This issue is holding me up from upgrading
the system to include central air. I could not immagine having to put
up with this all year.

To help reduce the noise as much as possible I would like to insulate
the walls in the closet, wrap the furnace and exposed duct whith
insulation, and install a solid door. If possible maybe even duct the
air return in from the attic. The previous owner has a 6' x 5'
circular foil vent that runs into the attic. I think this should be
sufficient for ventalation and pilot lights after I make the changes
above.

Am I on the right track here or am i going to creeate a series of
code violations?

Welcome all ideas and suggestions.

I would start by slowing the blower speed down.

Yes, there are issues concerning adequate heat transfer
and overheating the furnace, etc. And possible problems
with getting enough airflow over an evap coil with A/C.
But that's where I would begin experimenting.

I have a hunch that you could put enormous effort
into "soundproofing" the closet and still have the
big "whoosh" sound.

Jim

As per Speedy Jim's comment...

"I have a hunch that you could put enormous effort
into "soundproofing" the closet and still have the
big "whoosh" sound. "

your best return would be from reducing air flow speed (either by
reducing fan speed or increasing louver / duct size)

IMO the soundproofing isn't going to give you much bang for your buck
cuz' the open end of the duct (at the louver) will still be
broadcasting the noise.

I have an old house where the previous owner had forced air installed
to replace the original gravity system. The installers hacked into a
bathroom cabinet to install a return air duct. I just recently re-did
the job properly by finishing of the duct work & building a false
bottom in the cabinet. I calc'd my "duct work" size & then tested my
design by running the furnace periodically during the construction. I
didn't want to build in wind tunnel noise to the system.

The result was no noisier or quieter than the existing installation.

If you want quieter, you need lower air velocities.

Try running it with the louvers removed....see if that gets you a
noise level you can live with.

If not lower fan speed or bigger duct louvers. :(

cheers
Bob

How to quiet a Loud Furnace?
 

BobK207 wrote:
On Jan 7, 6:06 pm, Speedy Jim wrote:

wrote:

I have a small utility closet whith louvered doors which houses the
hot water heater and the gas forced air furnace. My issue is that this
closet is just off to the side of the living room and the return is
one large vent facing directly into the room. When the furnace kicks
on the sound of the motor, fan, and rushing air through the ducts is
extremly loud and anoying. This issue is holding me up from upgrading
the system to include central air. I could not immagine having to put
up with this all year.

To help reduce the noise as much as possible I would like to insulate
the walls in the closet, wrap the furnace and exposed duct whith
insulation, and install a solid door. If possible maybe even duct the
air return in from the attic. The previous owner has a 6' x 5'
circular foil vent that runs into the attic. I think this should be
sufficient for ventalation and pilot lights after I make the changes
above.

Am I on the right track here or am i going to creeate a series of
code violations?

Welcome all ideas and suggestions.

I would start by slowing the blower speed down.

Yes, there are issues concerning adequate heat transfer
and overheating the furnace, etc. And possible problems
with getting enough airflow over an evap coil with A/C.
But that's where I would begin experimenting.

I have a hunch that you could put enormous effort
into "soundproofing" the closet and still have the
big "whoosh" sound.

Jim


As per Speedy Jim's comment...

"I have a hunch that you could put enormous effort
into "soundproofing" the closet and still have the
big "whoosh" sound. "

your best return would be from reducing air flow speed (either by
reducing fan speed or increasing louver / duct size)

IMO the soundproofing isn't going to give you much bang for your buck
cuz' the open end of the duct (at the louver) will still be
broadcasting the noise.

I have an old house where the previous owner had forced air installed
to replace the original gravity system. The installers hacked into a
bathroom cabinet to install a return air duct. I just recently re-did
the job properly by finishing of the duct work & building a false
bottom in the cabinet. I calc'd my "duct work" size & then tested my
design by running the furnace periodically during the construction. I
didn't want to build in wind tunnel noise to the system.

The result was no noisier or quieter than the existing installation.

If you want quieter, you need lower air velocities.

Try running it with the louvers removed....see if that gets you a
noise level you can live with.

If not lower fan speed or bigger duct louvers. :(

cheers
Bob
Hi,
Lowering blower speed is upto a pint. If air moves too slow then you can
voerheat burner not extracting heat enough. Typically when cooling
blower runs at high, when heating blower runs at med. or med.-hi speed.
Also filter is part of air flow.