Boiler Room Sound Problem

Came across your excellent website using a Google search. I happen to be a contractor, and this is for a situation at my own offices. We have a boiler that is located in a separate room, but more or less in the center of our offices. The room is masonry and it has a fire rated door. I would like to install sound absorbent materials on the interior side of the block in the boiler room, as well as on the interior of the metal door to lessen the boiler sound that currently escapes from the room. Therefore, I need a product that can be somehow adhered. And while there is no open flame, due to the nature of the room I would prefer to use something that is not an outright fire hazard.

Your suggestions and assistance will be greatly appreciated.

Wantagh, NY


I only have a few products that will both absorb echo as well as block sound transmission. I will do my best to go through the basic idea of blocking sound and explain how each panel works, but if you have questions, please feel free to call. All of the products that I am going to suggest are Class A/1 Fire rated, and would adhere directly to the wall with adhesive. I would be happy to quote any or all of these options for you if you could let me know the square footage needed as well as your address.

Boiler or mechanical rooms are generally pretty noisy places. Not only are you going to have multiple noise sources but one will almost always find that these are rooms made up of all hard surfaces. The sound from the machines has no where to go, and the sound waves will just bounce from surface to surface. Believe it or not, the sound pressure in the room can actually be greater than the sum of all of the sound being made by the machines because of these reflections. So, I would suggest a product that will not only help the existing wall block the sound from leaving the room, but also absorbing the reverberation inside of the room itself.

The first and most effective is the Melamine Composite acoustical panels. These panels are made from the standard acoustical foam that pretty much everyone is familiar with. In the center of these panels is a layer of Mass Loaded Vinyl noise barrier which is basically a technology that has been designed to replace lead. As the sound wave hits the dense vinyl, it will move or vibrate the vinyl slightly turning the sound energy into heat energy which is how the sound is blocked. These panels have an STC (sound transmission coefficient) rating of 27, which basically means that they stop 27 dBa from passing through them. This rating is an average of high, mid and low frequencies but please keep in mind, the lower the frequency, the easier it is for the sound to make it’s way through pretty much anything you put in front of it. The melamine composite panels also have a soft foam surface which will help reduce the echo and reverberation in the room. The NRC (noise reduction coefficient) of these panels is .85 which means that essentially eighty-five percent of the sound that hits the surface will be absorbed. A ballpark price for the melamine composite panels is $11.00 per square foot.

Melamine Composite Panels

ThicknessSTCNRCCost Per Sq. Ft.

Another panel that you might want to consider is the Sound Silencer panels. These are a panel made from a polypropylene bead board, and although they are more cost effective than the previous option, they are also slightly less effective. Here is the data for the product:

Sound Silencer Acoustical Panels

ThicknessSTCNRCCost Per Sq. Ft.

One other option is the Echo Eliminator Composite panels. This is a cotton based panel with an aluminized mylar facing on one side. The NRC is .90 and the STC is 17. Ballpark cost is $7.00 per square foot.

Echo Eliminator Composite Panels

ThicknessSTCNRCCost Per Sq. Ft.

The panel that will be the best option for you basically depends on what you need acoustically as well as the budget that you have for the project. I would be happy to talk to you about the products and even get some product samples and literature out to you. All of the links above will take you to the respective web pages on my site, and at the bottom of each page you will find a PDF icon that will bring up a printer-friendly format of all of the product information.


  1. Mark Keenan

    Great Website! I’m looking for a way to reduce noise from an air compressor in a home shop. Your blog has been great at helping me understand the fundamental issues, the fish tank analogy especially. It would seem like an enclosure would be the easiest approach, I’m considering basically building it a small frame wall with quietrock on both sides and mineral fiber between, but the air exchange for cooling has me at a loss. Any ideas on how to create an exhaust and return without losing too much of the benefit (or breaking the bank)?

  2. Ted W


    Thanks for the compliments on the blog! It’s always great hearing that people find my online ramblings helpful.

    I have helped quite a few people make enclosures for compressors and shop vacuums, including a few friends of mine here locally. This would be my suggestion:

    • Start with a wooden frame and build the walls of the enclosure with 3/4″ MDF board and possibly a layer or two of standard 5/8″ sheetrock. The ability of the wall to block sound is going to come down to overall weight – the heavier the better.
    • Make sure your cuts are straight and seal any and all possible air gaps with a good acoustical sealant.
    • Seal your door with a closed cell weather stripping that can be purchased from the local hardware or home supply store. Air tight and mass are critical.
    • Keep in mind that this machine is going to need some cool air. I have had people make false floors or open-ended saw fits on the outside of the enclosure. These types of things need to eliminate the line of sight in/out of the enclosure and be lined with an absorptive material. Think of a muffler for a car. Air can get in/through the thing but it has to make an S or C shape and be passed by some kind of absorber.
    • For most of these enclosures, the builder will line them with the Echo Eliminator – which is an acoustical panel made from recycled cotton. It is a very cost-effective and easy-to-use material that will do a good job at reducing the reflections and reverberation inside of the enclosure. It is sold in 2’×4′ panels and can be cut with a good, sharp scissors. You can install it with liquid nails, or similar construction adhesive, and spray adhesive.

    Here is an example of a sound enclosure for a shop vac. This shows you the use of the false floor along with the recycled cotton Echo Eliminator panels. What you can’t see in those pictures is the exhaust hole in the back of the enclosure, under the false floor, but it i there.

    Please feel free to get back to me with any additional questions or concerns you have. I would be happy to help.

    Thank you,

  3. Joe stearns

    I found your web site very interestingI have a newly built home shop that has a major echo problem making it very difficult to carry on a conversation with someone. The shop is 24×40 with 10th ceiling. Concrete floor, drywall on walls and ceiling with an 8×16 insulated overhead door.
    What would you recommend to control this echo problem?

    Thanks, Joe

    • Ted W

      Hey Joe,

      Thanks for the comment. We have a few different products that will help to control the echo and reverberation of the space – all of these have their own respective advantages and disadvantages. Considering this is a fairly large area, and also considering that aesthetics are probably not as critical as performance and budget – after all, this is a shop, not a dining room – I would probably suggest the Echo Eiminator panels.

      These panels are made from recycled cotton. They are cost-effective and easy-to-install onto walls or ceilings – generally with adhesive. They are not sold or marketed to be the most finished looking or decorative panel in the world – they are really more utilitarian and cost-effective.

      Based on the size of your shop, I would suggest starting with 30 panels and then take a step back to listen and re-assess the situation. If you need it a bit quieter still, you can always install more. Thirty panels with adhesive and shipping will probably run you about $600, depending on the particulars of the order, but that’s a safe ballpark.

      The location of the panels is not going to be critical to a space like this, so I would suggest that you install them relatively evenly throughout the room – most likely on the ceiling. They will see less contact and dust on the ceiling. The only exception is that if you have one or two particularly loud machines (like a dust collector or some other noise source that runs frequently), you can get a bit more out of them if you put them on the wall(s) nearest the machine – usually behind them.

      We have a customer testimonial for a small print shop with an echo problem that used our Echo Eliminator panels.

      Let me know if you have any more questions! Thanks,

  4. Jim

    I love this site. I just purchased a Levittown style house that was the boiler in the middle of the house. When it kicks on, it makes a very loud reverberating noise. It is in a small closet sized area with a folding door that has slats (I think to let air get in to the boiler).
    Is there anything I can safely do to reduce a lot of the noise? It is a fairly new boiler that is serviced regularly and it doesn’t make any abnormal squeaking sounds or things of that nature.

    Thank you for Any advice you can give me!!!


    • Ted W

      There are a few things that you might want to explore before you proceed with any kind of treatment. The first thing to look for is any kind of structure-borne vibration energy that is transmitted to the rest of the house by the studs and drywall. If that type of noise/problem is present, it’s going to need to be approached first.

      If the machine is just creating an airborne noise and that is the problem, it is a lot easier to approach. If you put a noise source into a small room or enclosure that has one open wall/door, all of the sound being made by that machine bounces off of the walls around the machine and out in one direction. Imagine the utility room filled with water. Where is all of the water pressure going to go? The door, in this case, is acoustically invisible and they are almost always installed because the machine needs the airflow to work properly.

      If the sound problem is airborne noise (not vibration), you can line the inside of the closet with one of a few different products to reduce reflections off of the back and side walls. This will offer a bit of relief (2-4 dBA in most cases), which can be preceived as a 20-40% reduction in sound. Getting above and beyond that is going to mean adding a fresh air intake (possibly an exhaust) and swapping out the door.

      Hopefully this helps,

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