[macnewma]

I am not sure if this is the appropriate circle for this discussion, but I will give it a shot anyway.

I am moving to a new home and my listening room will be adajcent to the room housing the HVAC and water heater.  The HVAC makes a wonderful hum and rattle...but not exactly music to my ears.  This is a problem because the door leading to that room is the cheap "slatted" style.  I am not sure if this for some sort of code for ventilation.

I would like to do something to solve this problem and quiet the listening room.  Maybe replace the door with a solid-core door?  I am concerned about code though.  Maybe put up acoustic curtains behind the door?

Any ideas?

Thanks in advance-

Max

[JoshK]

How about lining the inside of that room with acoustic foam (non flamable of course) to deaden the sound?  I am not sure about the code with the slated door, that does sound like a code thing.  I would line the door as well but maybe leave the slate uncovered.

[John Casler]

I am not sure if this is the appropriate circle for this discussion, but I will give it a shot anyway.

I am moving to a new home and my listening room will be adajcent to the room housing the HVAC and water heater.  The HVAC makes a wonderful hum and rattle...but not exactly music to my ears.  This is a problem because the door leading to that room is the cheap "slatted" style.  I am not sure if this for some sort of code for ventilation.

I would like to do something to solve this problem and quiet th ...

The unit "draws" its air to recirculate through the "slats".  If you put in a solid door it will seal the compartment and the unit will not work.

try opening the door or slightly propping it open, which will reduce air turbulence and noise, but if the unit itself is noisy, just shut it off (switch on the thermostat) when seriously listening.

[Marbles]

I had a similar problem with my 26 year old systems.

One is in a room on the other side of a wall from where my head is when I sleep and the other (2 furnaces and two centrail air conditioners) is next to my main listening/HT room.

We started to have some problems with the CA so we replaced both furnaces and AC's about a month ago.

To quiet them, the installers used coated canvass between the coils (they sit on the furnace) and the metal duct work.

That is instead of having metal in contact with metal, they de-coupled the metal and the fan vibration from the duct work with cloth ie canvas.

They also set the furnaces on 2" foam.

This really quieted the furnaces down A LOT.

I can hear when the furnace comes on in the middle of the night, but it is not bad.  Before you had to turn the TV up to hear it when the furnace kicked in, now with the TV on, you can't tell if the furnace is on or not.

In my HT room, I had them re-run a return to another room, and I can't hear the furnace/CA at all.  With or without music on.

Both new furnaces are more than 90% effecient and needed to draw air from outside.

In the upstairs one, there was not enough return duct work so it was pulling air over the grids way to fast and it vibrated in a bothersome way.

They put 2 more returns in, and used heavy duty wall covers (wider slats, and thicker slats).  This helped as well.

[Marbles]

To clearify a little further:

Normally you would have: furnace/CA coils/ductwork.

With mine they are foam/furnace/CA coils/about 2" of treated canvas/ductwork.

The vibrations from the fan do not make it to the metal ductwork to resonate as the canvas decouples the duckwork.  The foam beneath the furnace helped reduce these vibrations as well.

The only sound I get is the ambient sound of the gas burning and the fan.

These are very very low.

[JLM]

Additional ideas:

Replace the slotted door with a solid/insulated/sealed (typical) exterior door.

Add another source for fresh air to the furnace.  Marbles is right, you can't stave the furnace for air.  Fresh air allows for replacement of oxygen that you and your furnace both need.

Use of lined fiberglass rigid or flexible ductwork instead of sheetmetal ductwork.

About 10 years ago I designed and built an addition that had the furnace in a separate room.  The only door to the room was on the exterior and the walls were insulated.  Two louvers (with insect screens) were added for outside/combustion air.  So essentially the furnace was in an outside space.  All ductwork was rigid and flexible lined fiberglass.  You could barely hear the furnace run.

[macnewma]

Thanks guys.  Obviously, I don't know any thing about furnaces  

I think isolation of the unit itself will be the best solution.  Maybe baffling the room with foam so that air can still move to the unit, but sound will have to bounce off of multiple absorbers.  

What do you guys think about hanging some acoustic curtains from one wall to the other, basically splitting the room and hopefully blocking the noise, but allowing the air to move.

Looks like I will have to get creative on this one.

Thanks for the help-
Max

[macnewma]

As a follow up, I did some searching online and found this site:

www.soundproofing.org

They sell sound deadening/proofing material.  I emailed them and asked them what to do about my vented room.  They suggested dampening the HVAC unit itself and creating a baffle.

Here is a drawing of a rough design I sent them for confirmation:



He suggested that this would work.  I am not sure what materials to use or exact dimensions, but I think it will be a fun project.  Does anybody have any ideas on how to make the most effective baffle?

My concerns are:

1.  Materials (Plywood, MDF???)
2.  Dimensions such as width of passage way
3.  How much sound deadening and what type of sound deadening to line the baffle with

Max

[markC]

Being a HVAC tech., I may be able to help. If your appliances are fossil fuel fired, (gas or oil), you MUST have supply air for them. If not, the appliance will begin "back drafting or spilling" when it begins to run out of oxygen. When this happens the byproduct of the burning fuel which is c02 gets reused in the fuel air mixture and c0 is then the byprduct being produced. One solution would be to bring in fresh air from outside, (if possible), via an insulated duct,( to avoid condensation). If your furnace is direct vent, (high efficiency), with it's own pipe to bring in fresh air, then your only concern is the water heater. Another option, (if layout allows it), is to put grilles on the wall of the mech. room that opens to another room other than your listening room. If you satisfy the combustion and dilution air requirements in one of the above ways, then you can go ahead and acoustically insulate the walls of the mechanical and add a solid door. If not, don't even think about sealing off that room. Carbon Monoxide KILLS!

[rosconey]

i agree find another way for air intake and add a solid door-do you have a stair well next to the utility room?ive seen vents on walls under stairs quite a bit-or another room that shares a wall with the utility room, and revent that way.