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DIY Generator Enclosure: Easy-To-Follow & Budget-Friendly Process of Soundproofing Boxes

Brown container box

Last Updated: May 9, 2024

Is your generator making a lot of noise?

Been there.

The noise might not be bothersome under normal circumstances.

But listening to it for hours, in case of power outages or any other emergency, can be nerve-wracking (at least it was, for me).

Let me tell you what I did: I decided to build a soundproof generator box, and if you are considering that option, then read on as I explain the easiest way to make a DIY generator quiet box.

Things You Will Need In Building Enclosures

Building a DIY generator enclosure is not difficult once you have all the necessary tools and materials.

Before we move onto the steps for building a generator noise reduction box, let us have a look at the list of things you will need:

  1. Medium Density Fiberboard (MDF) to make the box
  2. Mass Loaded Vinyl as the first soundproofing layer
  3. Foam Mats for an additional soundproofing layer
  4. Green Glue Compound to stick the layers together
  5. Flexible Metal Duct Pipe and ventilation materials for air intake, cooling, and exhaust

You might also need other things, such as hinges, receptacle boxes, and even wheels. This will depend on the design of your DIY generator enclosure. 

Steps To Build A DIY Generator Quiet Box

Step 1: Measure The Size Of Your Generator

blue and black generator

Generators are available in many different sizes, so the first thing you need to do is measure the size of your generator to build a generator silencer box accordingly.

Make sure the measurements are accurate and precise; otherwise, you will end up with a generator quiet box that is either too small to fit your generator or too large for it. All the hard work that you put into building it will go to waste.

It is a good idea to note down all the measurements in a notebook as this will minimize the chances of error.

I would suggest that you add an inch or two to the original measurements as a margin of safety.

Step 2: Cut The Sides And Top Of The Generator Box 

Once you have taken the measurements, the next step is to cut the box accordingly. For the box, I recommend using Medium Density Fiberboard (MDF) as it is durable and more soundproof.

You can use plywood too, but it does not offer the same level of noise reduction as MDF.

Like the measurements, the cutting of the box needs to be accurate and precise too. Start by marking the measurements on the material with a pen or pencil, and then cut it with a circular or table saw.

Make sure you buy enough MDF or plywood and the correct size if you want to avoid extra trips to the hardware store. I ran short of it during the construction, and going back and forth to the hardware store was a hassle. 

Step 3: Make Holes In The Box For Ventilation

After cutting the generator box according to the measurements, you need to make some holes for ventilation. Make sure you buy ventilation ducts when purchasing material for the DIY generator enclosure.

Once you have it, follow these steps:

  1. Measure the diameter of the ventilation duct.
  2. Mark the first circle on the top part of the box.
  3. Mark the second and third circles on the side of the box facing the wall.

After you finish this, lay the fiberboards on a table. Keep the top part in between and the walls in its surroundings.

Step 4: Glue And Caulk The Soundproofing Layers Using Green Glue

The key to soundproofing your generator box is to add layers of free space that dissipate the sound. Ideally, you should add at least two layers of soundproofing material as an effective way on how to quiet a generator.

To make your generator box soundproof, the first layer you should add is a Mass Loaded Vinyl (MLV). This material acts as a sound barrier. It is made from vinyl and is supposed to block the sound generated by any device or machine.

According to my research and experience, the second layer you should add is foam mats. These mats are made from closed cell vinyl nitrile, an effective soundproofing material.

Cut the MLV according to measurements and paste it on the MDF. Although the MLV already has glue on it, I would suggest using a green glue compound to stick the material onto the box surface as it improves the soundproofing quality of the box. Repeat the same steps for the second layer, and you will be done.

roll of black vinyl

Step 5: Assemble The Generator Quiet Box

Finally, it’s time to assemble your generator quiet box! Attach all the four walls, one by one, using nails or screws. I used the latter so that I can modify or disassemble the generator box if needed. After this, attach the top of the enclosure to the walls and screw it down carefully.

How you design the generator box is up to you. You can even add a small door to make the generator easily accessible.

Step 6: Install The Ventilation Ducts

Once you assemble the box, the last - and perhaps most important - thing you need to do is install the ventilation ducts. Take the ventilation ducts you purchased with the other material, and attach them to the holes you created in step 2.

I cannot stress enough the importance of installing the ventilation ducts properly. Good airflow is essential for the proper functioning of the generator such as a quiet propane generator. So, make sure you focus on this part.

Frequently Asked Questions

1. Will a generator overheat in a box?

Yes, a generator can overheat in a box if there’s no proper ventilation. So, make sure your DIY generator enclosure has at least three ventilation ducts: one for the exhaust fumes outlet, one for cooling the generator, and one for air intake.

2. How do you soundproof a generator box?

As I explained above, soundproofing a generator box involves caulking layers of mass-loaded vinyl, foam mats, and other soundproofing material on the inside of the DIY generator enclosure.

Ideally, you should caulk at least two soundproofing layers to build a proper generator noise reduction box.

3. What to consider when designing a quiet box for a generator?

When designing and building a generator quiet box, there is a lot to consider.

Making something soundproof usually means making it airtight, and that is not easy when the thing in consideration is a generator - a machine that requires proper ventilation for functioning.

Firstly, you need to consider the type of generator silencer box you need. Will it be collapsible or permanent? Additionally, you also need to make sure that there are three ventilation ducts in the box, as you will use each of them for a different purpose.

Besides this, how often the generator is going to be used is another important factor. If it is used daily or moved from one location to another very often, that will affect the design. Another thing that affects the design is the way the generator is started and stopped.

Last but not least, you need to take your budget into account.

The cost of a generator soundproof enclosure can vary depending on the design, so keep that in mind before starting.

Take a look at this design of a generator quiet box:

4. How to build a baffle box to quiet a generator?

You can follow the above-mentioned steps to make a generator baffle box. 


Building a soundproof generator box is not a piece of cake, but I can safely say that this is a DIY project you will not regret. I hope this comprehensive guide will help you make a DIY generator enclosure easily!

Plus, a “do it yourself” generator enclosure is much cheaper than a ready-to-use generator box. This means you will not only get a fun activity to do, but you will also save a few bucks in the process.

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