How To Build a Soundproof Generator Box (Step by Step)

How To Build a Soundproof Generator Box

Generators are a great way to provide power to your home during power outages, but they can be extremely loud. Nobody wants to have to hear the constant noise that comes from a generator during power outages; it just becomes annoying. What if you could create a soundproof generator box so you wouldn’t have to hear the loud humming noise the generator emits?

Well, the good news is that you can do this!! In this article, we’re going to go over the steps that you need to take to create a soundproof generator box, so you don’t have to hear the annoying hum of a generator during power outages. 

What You Need

Before we get into the materials that you need to complete this project, let’s go over a couple of terms:

  • Medium Density Fiberboards (MDF). This is the primary material that you’ll use to make the box
  • Mass Loaded Vinyl (MLV). This is the first layer in your soundproof generator box when it comes down to soundproofing
  • Foam Mats. Another layer that you use in your soundproof generator box for soundproofing
  • Green Glue. This is used for gluing edges down and is another soundproofing tool
  • Ventilation Ducts. These are used to create a nice supply and airflow for the soundproof generator box

Now that we have those out of the way, let’s talk about what you need:

Remember that you’re not going to be able to completely soundproof your generator because the box needs vents, so the generator doesn’t overheat. These holes will make it so some of the sounds from the generator will come out of the box, but it’ll be less than if you didn’t have a soundproof generator box. 

Step 1: Take Measurements

Photo by Olga Kononenko on Unsplash

Something that you need to know before we begin is that generators are made in a variety of sizes.

Therefore, all soundproof generator boxes do too.

The first thing that you need to do is to take measurements of your own generator before you can make your box. When doing this, make sure that you’re paying attention when taking the measurements – this is incredibly important.

If you make a mistake while measuring your soundproof generator box, you probably won’t have enough room to finish building the box.

Live by this motto: measure twice (or three times!) before you begin cutting.

After you have the right measurements, make sure to jot them down somewhere. Add a few inches to each side because you must have space for the vents and insulation thickness.

When everything is measured, and you’ve added a few inches on each side equally, write down the final measurements. Now we can get started on making your soundproof generator box. 

Step 2: Cut Out the Box

Photo by Kaboompics .com from Pexels

Now that you’ve got your measurements written down, take your medium density fiberboard and get ready to cut.

While you don’t need to use MDFs, it helps with the soundproofing. If you aren’t able to find MDFs, you can use regular plywood, but it will be a little less effective at soundproofing than if you used fiberboard. Above you’ll find a link to some great MDFs that you can use for this project.

Using your pen and the right-angled ruler, mark the measurements on the MDF. Double, or triple, check your work and then get ready to cut.

Using your circular or table saw, whichever you’re using, cut out the board. Make sure that you’re paying close attention to the labels and measurements on the board that you made previously.

Do this for all of your boards. 

Step 3: Make Ventilation Holes

Take the ventilation duct that you purchased for this project and measure the diameter. Now it’s time to mark out two circles on your fiberboard:

1. The first mark should be located on the top (ceiling) piece of your box. You want to place the circle closer to one side instead of in the middle of the board.

2. The second circle should be placed on one of the boards that are meant to be a side (or wall) piece. Mark the circle on the other side from where the top hole is located.

After everything has been marked as specified by the instructions, lay down your “walls’ on a table, placing the “ceiling” one in the middle with the rest of the “walls” around it. 

Step 4: Add the MLV Insulation

The thing you need to know about soundproofing is that layers are important. Layers of sound gaps and free space, layers of materials, layers of everything. A great material to use for soundproofing is MLV insulation – this is the first layer that you will use to build your soundproof generator box.

The first thing you want to do is measure the pieces of MDF that you cut out for the box and cut the MLV to that size and glue it down directly to the inside side of your soundboards. 

Step 5: Caulk the First Layer of Insulation

The edges of the MLV insulation can be difficult to glue down properly, so you’ll want to use green glue to take care of this problem. 

Step 6: Glue the Foam Mat Down

Foam mats will help drastically reduce the noise of your generator in your soundproof generator box. So, what you’ll do is add this layer onto your walls and ceiling of your soundproof box.

You’ll want to take the mats that you have and label the measurements of your walls and ceiling and cut them accordingly. Glue the mats down on top of the MLV and repeat the same with the edges with the green glue.

Step 7: Put the Box Together

Assemble the walls around the ceiling and nail or screw them into place. You can also install some hinges so you have easy access to your generator. 

Step 8: Install the Vent Duct

Place the vent hoses into the holes that you created in step 3, and make sure to tighten them into place because you don’t want them jumping around. The final touch to your soundproof generator box would be to add a little vent right above the openings. Once you’ve completed all of these steps, your soundproof generator box is ready to be used! If building a soundproof box for your generator is too much work, or you want to start with the most quiet inverter possible, check out matt´s article on the most quiet generators at

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