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Soundproofing a furnace room

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[OP]
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Oct 16, 2001
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Soundproofing a furnace room

Was thinking my next project would be to soundproof, or at least dampen the sounds coming from our furnace room.

Currently have 3 things that create noise, furnace, pump for out waterfall and a water pump for our cistern.

Out of the 3 the water pump is the worse and can be heard throughout the house when running. Something we got used to, and not while deafing, its sure noticeable

Without a major reno of ripping out thinkgs, what would be the best way. Read up on Roxul bats as well as the hard Styrofoam SM. I wouldnt be finishing the inside of the walls with anything, besides plastic if I went the bat route.

Room would also need to be done best as I can reach.


Who has done a project like this?
30 replies
Deal Addict
Mar 11, 2007
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5/8 drywall, roxul, 5/8 drywall. If you can, another layer of drywall installed if the opposite side.
[OP]
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jfmartel wrote: 5/8 drywall, roxul, 5/8 drywall. If you can, another layer of drywall installed if the opposite side.
Outside of the walls are already finished. I'll think about another drywall layer but I want access to the things run in the wall if needed
Deal Expert
Oct 6, 2005
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A lot of the noise maybe travelling through your vents - so even if you soundproof the room there will be a lot of noise leakage.
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Jan 28, 2014
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coolspot wrote: A lot of the noise maybe travelling through your vents - so even if you soundproof the room there will be a lot of noise leakage.
Agreed - that is if coolspot and I are thinking of the same type of "vents". If you are referring to the vents that are outside your house for the high efficiency furnace or a power vented water heater then yes, they make a heck of a lot of noise.

We do not have them as yet - that will be next. But the people next door do and I can hear the racket when our furnace and fridge kick in and when the bathtub is filling - and I mean all at the same time. Frankly I hope they can hear it too!

My sister-in-law recently purchased a house and couldn't understand what was keeping her up all night - then she realized it was the venting that is right under her bedroom window. She now sleeps in the basement. Relatives visited and were appalled that she offered them use of the entire main floor - they didn't want to put her out. No problem as far as she was concerned. It didn't take them long to figure out why.

Fortunately the main bedroom in our bungalow is on the other side of the house in question.
Deal Expert
Jan 27, 2006
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The other issue is what the furnace, and the various water pumps are mounted on and how well they are mounted on it.

Example - if the furnace isn't secure, it will "bounce"/vibrate against the floor causing a lot of extra noise.
Sr. Member
Nov 21, 2010
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Ontario
Keep in mind that if the furnace is not a high efficiency unit it has to get its combustion air from somewhere so you can't seal the room up tight.
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Jan 27, 2006
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retrovette wrote: Keep in mind that if the furnace is not a high efficiency unit it has to get its combustion air from somewhere so you can't seal the room up tight.
According to code, there should be a cold/combustion air intake pipe coming in from the outside for any furnace room with enough air for any and all combustion based devices. These pipes are typically not connected directly to the device but rather terminates somewhere close to it. I had an existing one for the furnace and then when I put in my tankless 13 years ago, the city had me put in another one so I have two air intake pipes going to the furnace room.
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Oct 6, 2005
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Blanche123 wrote: Agreed - that is if coolspot and I are thinking of the same type of "vents". If you are referring to the vents that are outside your house for the high efficiency furnace or a power vented water heater then yes, they make a heck of a lot of noise.
I mean the general duct work - you can seal up the room, but the metal ductwork will still conduct the sound throughout the house :D
Deal Expert
Aug 2, 2001
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Because the furnace has duct work running through the entire house, it would be hard to seal all the joints. Because of this, I would seal off the two pumps independently. Ensure they have whatever the required air flow is for cooling, and build them their own "room" around with sound deadening material and isolate them from the floor (if floor mounted) in case it causes vibrations and/or the ground transmits noise.

I am unsure how big these pumps are, however you will notice a much better result by isolating each of the pumps rather than trying to isolate the entire room. Your furnace room has many "leaks" you will never fix with all the duct work and piping, so by isolating the pumps you have a better opportunity to isolate the biggest offenders.
Sr. Member
Nov 21, 2010
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Ontario
craftsman wrote: According to code, there should be a cold/combustion air intake pipe coming in from the outside for any furnace room with enough air for any and all combustion based devices. These pipes are typically not connected directly to the device but rather terminates somewhere close to it. I had an existing one for the furnace and then when I put in my tankless 13 years ago, the city had me put in another one so I have two air intake pipes going to the furnace room.
At one time all they did was put a grill near the bottom of the door going into the furnace room and it got its combustion air from the house. We don't know if his house was built before that code rule you mention.
The op didn't say the type of furnace he had so I thought I'd throw that comment in for him just in case.
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Oct 16, 2001
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TrevorK wrote: Because the furnace has duct work running through the entire house, it would be hard to seal all the joints. Because of this, I would seal off the two pumps independently. Ensure they have whatever the required air flow is for cooling, and build them their own "room" around with sound deadening material and isolate them from the floor (if floor mounted) in case it causes vibrations and/or the ground transmits noise.

I am unsure how big these pumps are, however you will notice a much better result by isolating each of the pumps rather than trying to isolate the entire room. Your furnace room has many "leaks" you will never fix with all the duct work and piping, so by isolating the pumps you have a better opportunity to isolate the biggest offenders.
this might be the best bet. The furnace doesn't make noise that is heard throughout the house, besides air of course from the vents. The water fall pump is only really heard at night when everything is off, and if you are in the basement. That I have an idea how to fix.

|the water pump for drawing water in is the worse. It is mounted on a piece of wood which is sitting on the cement floor. The noise from it isn't vibration or anything, its just the noise of the pump. I think I will look into a breathable box for this that could be insutlated to muffle the sound
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Jan 28, 2014
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coolspot wrote: I mean the general duct work - you can seal up the room, but the metal ductwork will still conduct the sound throughout the house :D
I thought we might be referring to different "vents". But I have to tell you that the outside white vents make one heck of a racket.

Strangely the sound of the furnace is comforting to me - but not the a/c. Probably has something to do with always being freezing - even in our so-called summers. I like it hot but without sun - I burn very easily and have rosacea. Some people like the sound of rain - I like the sound of heat.
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Oct 19, 2008
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craftsman wrote: The other issue is what the furnace, and the various water pumps are mounted on and how well they are mounted on it.

Example - if the furnace isn't secure, it will "bounce"/vibrate against the floor causing a lot of extra noise.
+1

Eliminate as much of the noise as possible before trying to soundproof. Rattling panels on furnace from crap fastening systems etc. The water pump is bothering OP most....is it mounted on sound dampening material? Start there...and can the pump safely be encased in a rigid foam box....if that won't affect operation it would be easier than soundproofing the room.
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Zamboni wrote: +1

Eliminate as much of the noise as possible before trying to soundproof. Rattling panels on furnace from crap fastening systems etc. The water pump is bothering OP most....is it mounted on sound dampening material? Start there...and can the pump safely be encased in a rigid foam box....if that won't affect operation it would be easier than soundproofing the room.
Furnace is secure as is all the metal. sounds from the room aren't rattles, just noise of the furnace fan (which is normal). The water fall pump I looked at again and it was the vibration of the pump going from the plastic reservoir to the metal box its in. A few pieces of cardboard took care of that noise

Water pump is the biggest culprit. Noise from it is just because the pump is loud. I will look into maybe trying a different base, or rubber between the wood and the bottom of the pump, but basically its just a loud pump. I will look into a Styrofoam box and see how that helps. even the old school white coolers you can get would work (if they still exist) and then put a vent in the top for air (if needed) Not sure how much heat it would trap and how that would affect the pump

If I could lower that, then the other sounds to me would just me normal operation sounds that a furnace room provides
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Oct 6, 2005
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Spidey wrote: Water pump is the biggest culprit. Noise from it is just because the pump is loud. I will look into maybe trying a different base, or rubber between the wood and the bottom of the pump, but basically its just a loud pump. I will look into a Styrofoam box and see how that helps. even the old school white coolers you can get would work (if they still exist) and then put a vent in the top for air (if needed) Not sure how much heat it would trap and how that would affect the pump
Yeah, water pumps are noisy if you're on well water, but it shouldn't "shake" the whole house. You may want to get your pump tuned up - check to ensure it is inflated/tuned to the proper pressure. Perhaps the pump is coming on too often? Are you getting a lot of water knocking too?
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Jul 13, 2010
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Pictures might help.
  • sound insulate the room. There is sound deadening characteristics with Roxul, drywall, etc... and you can actually look up the specs for these materials. It all has to do with resonance of the materials and the frequency of the sound. Using drapes or egg cartons on the walls will absorb some of the sound for example. Your furnace room is probably unfinished and echos the sound like a bathroom or gymnasium.
  • sound insulate the items causing the noise or get ones that are quieter. When in the military we use to dig a hole and put the generator in it so it wasn't heard easily away from base camp. It made a world of difference.
  • you could create white noise to offset
There are even things called "bass traps" that will suck the bass in a room to try and remove it. Wouldn't work here but I am trying to make a point about the technical aspects of sound.
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[OP]
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coolspot wrote: Yeah, water pumps are noisy if you're on well water, but it shouldn't "shake" the whole house. You may want to get your pump tuned up - check to ensure it is inflated/tuned to the proper pressure. Perhaps the pump is coming on too often? Are you getting a lot of water knocking too?
I never said anywhere it shook the house, I said it was noisy. Pressure turn on and turn off are fine, and with in the specs of the pump. We have a storage tank inside as well so it doesn't go off with every toiltet flush, etc. No water knocking either. The pump had always been loud, some pumps are just quieter than others. We didn't install it, so maybe they original owners bought a cheaper louder one. Not sure
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Dec 28, 2004
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Our laundry closet is right off our living room dining room.

It had bifold doors and has washer, dryer and electric hot water heater in it. I would love to find a way to sound insulate it better.

Does anyone have any recommendations?
At some point I might try to move the hot water tank into the crawl space below it and replace it with a utility sink. But not right away.
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Apr 20, 2011
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budfrogs wrote: Our laundry closet is right off our living room dining room.

It had bifold doors and has washer, dryer and electric hot water heater in it. I would love to find a way to sound insulate it better.

Does anyone have any recommendations?
At some point I might try to move the hot water tank into the crawl space below it and replace it with a utility sink. But not right away.
Mine had bifold slats (essentially no door, pretty much)
Just got around to changing that to a proper door and it made a world of difference when closed.
If that's what you have, swap the door type first and go from there.

The walls currently have no insulation, so I guess that's my next step.
Probably won't need to go beyond that

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