Owning a generator ensures that you have access to power during an emergency. Operating one can be challenging.
Most generators are not designed to operate indoors. The exhaust emitted from the equipment is dangerous to human health.
When you run the generator outside, the noise it creates is massive and standing next to one can expose your ears to sound levels above 90 decibels!
Although inverters don’t have as much of an issue, the noise from a standard generator can disrupt an entire neighborhood. How can you get around this problem while still getting the electricity needed during emergencies?
The solution is to build a DIY generator sound enclosure.
Materials Needed for a Generator Sound Enclosure
- Table or Circular saw
- Cordless drill or Screwdriver
- Pencil
- Medium-density Fiberboard (MDF)
- Glue or Caulk
- Vinyl MLV Sound Barrier Material
- GreenGlue Sealant
- Closed-cell Vinyl Nitrile Foam Matting
- Galvanized Screws
- Hinges
- Vent Covers
Do I Need to Have a Soundproof Enclosure for My Generator?
Some generators operate at noise levels that may not need to have a soundproof enclosure. Several entry-level products fit into this category.
You can tell if one is necessary based on the specifications listed on the box, equipment, or owner’s manual. Anything that is rated above 65 decibels may require some soundproofing to meet neighborhood or community code requirements.
If you live in the country away from your neighbors, even a loud generator may not require a soundproof enclosure.
It would depend on whether you keep the equipment close to your house. Positioning it on the other side of a garage, wall, or structure could reflect enough sound away from the home to make it a suitable user experience.
What to Consider When Designing a Generator Quiet Box
Most people only use their generator a couple of times each year. Placing it in a soundproof enclosure can protect it from the elements while giving your shed or garage extra storage space, but you’ll still need to stabilize the fuel.
If it has been over a month since you’ve run the generator, you’ll need to check all of the fluid levels before cranking it up. When this equipment doesn’t have enough oil available, standard operations could burn out the engine.
You need to place the soundproof enclosure in a location where air circulation occurs. Although you’ll vent the exhaust out of the box, harmful gases could still linger in an area where no ventilation exists.
Since the exhaust may contain carbon monoxide, proceed with caution when you are working around an operating generator.
Steps to Build a DIY Generator Sound Enclosure
The goal of building a DIY soundproof generator enclosure is to decrease the noise output of your equipment by at least 20%, or to drop the decibel measurement under 50. Achieving either outcome gives you a successful experience.
These steps will help you follow that process.
1. Measure the Size of Your Generator.
A soundproof enclosure must encompass the entire generator. You also need room to incorporate soundboards within the structure to minimize the influence of audio waves in your neighborhood.
Once you’ve obtained the height, width, and length measurements of your generator, add 40% to your figures. That will give you enough room to create a dampening effect.
When you obtain the measurement, the height must be taken at the highest point on the equipment.
That could be the handle on the generator if you’re using a portable unit. The length and width must follow the same considerations.
As a general rule, it helps to measure twice and cut once to avoid having an error during this initial step.
2. Cut the Top and Sides of Your Box.
Outline the measurements on your MDF for the top and walls of your soundproof enclosure. It helps to label each piece so that you attach them in later steps correctly. Once you have the outlines in place, cut the boards to fit based on what you’ve traced.
Using a table saw for the cut reduces the risk of creating a curve or a crooked line. If you use a circular saw, position the MDF on sawhorses or boards to create a stable surface for the tool to navigate.
If you want a hinged top for your soundproof enclosure, route the top vent hole into the side wall instead. Having a top vent, with a door you can open, creates logistical issues with your generator hoses.
3. Create Holes for Ventilation.
Your soundproof enclosure needs two holes for ventilation to create a successful user experience. The top vent should be near the back of your equipment, where the engine operates on the generator.
For the second duct, cut out a piece along the side on the opposite end of the box from the first one.
Once you’ve taken care of this step, lay out the pieces to ensure that you’ve got everything you need. When the construction work begins, it isn’t easy to start over.
4. Add the Insulation to the MDF.
The best way to add a sound barrier to this box is to use materials that you can glue or caulk to the interior.
Your first layer should be the Vinyl MLV because it blocks noise through reflection instead of absorption.
When it is next to the exterior wall (along the MDF), it can push audio waves back to the generator instead of allowing them to escape.
Cover the box’s entire interior with the Vinyl MLV. Allow it to dry according to the adhesive or caulk used during this step.
When the adhesive is dry, place the GreenGlue soundproofing sealant along the edges of the vinyl to prevent areas where the reflected audio waves could escape. Each board should have a complete seal that covers the MDF and the added reflective agent.
5. Place Your Second Layer of Soundproofing in the Box.
Once the reflective qualities of insulation are in place with your box, add the second layer of soundproofing that absorbs the unwanted audio waves.
The best product for this step is a closed-cell vinyl nitrile foam mat. You’ll need to cut it to the same size as your walls and top to match the MDF.
Glue this material to the vinyl MLV already installed. Once it dries, add another caulk layer to the seams to create an insulative shield against the unwanted noise the generator produces.
Adding a second layer of soundproofing along the seams ensures that when you build the enclosure, it can absorb or reflect the most sound possible.
6. Assemble Your Box.
Once both insulation layers are dry, you are ready to assemble the box. Attach all four walls using galvanized screws since this installation is going to be outside. A simple butt joint works well for creating the soundproof enclosure.
Do not use nails for these joints. Most generators produce significant vibration that transitions from the ground to the enclosure. As time passes, that movement can shake the nails loose, causing your box to fail.
Once the box is assembled, affix the top by placing screws in each corner. You can use a hinged design, if you prefer, for easy access to the top of the unit.
7. Install the Ventilation Ducts.
Generators require an outside air supply to prevent the equipment from overheating. If you don’t have oxygen available, combustion will eventually fail, and you won’t get the power needed.
The best venting methods work like a plumbing trap in the bathroom. By creating curves in the structure, the audio waves lose their power while traveling through the structure. This process causes the eventual noise that escapes to lessen.
Thread the generator hoses into the holes you cut into the soundproof enclosure. You’ll want to incorporate a vent cover on each one to prevent animals and debris from clogging up your system.
If you have a top vent on your enclosure, a rainproof vent is necessary unless you have the box positioned under a protective cover.
FAQ about Soundproof Enclosures for Generators
Managing a generator can have some challenges, especially when you want or need it to be in a soundproof enclosure. These common questions often arise during the construction process.
■ Can You Build a Box around a Generator?
Building a DIY soundproof enclosure for a generator is typically permissible and included with residential zoning codes. Because you cannot be inside the box while the equipment operates, your structure should surround it while giving you outside access to it. There must be enough space for ventilation to have a successful experience.
■ What DB Is a Quiet Generator?
Most residential generators must operate at noise levels of 65 decibels or below. When the equipment creates sounds at that volume, it is equivalent to the average lawnmower operating in a yard. When you place an authorized baffle or soundbox around it, you can lower the output to under 50 decibels on some models.
■ Is It Legal to Enclose a Portable Generator?
When operating a portable generator in a soundproof enclosure, you must create more space for air circulation. It helps to build a venting portal into the structure to support the equipment pulling cold air in, while expelling hot air out. The size and shape of these models can vary, which means you might also have some measurement challenges to manage when producing the walls and ceiling of the box.
■ What Are the Different Noise Types?
Generators can produce two different noise types. The most common is called “airborne sound.” When the equipment operates, the audio waves from the power generation efforts travel through the air to impact specific objects. When that event occurs, the waves either reflect or absorb into the surface. The second is called “impact noise.” It happens when vibrations from the generator impact the ground, floor, or other structures.
■ What Is Sound Dampening?
Sound dampening is an active noise reduction effort that absorbs or reflects audio waves within an interior environment. When audio waves encounter these restrictions, the process lessens the decibels that a person hears on the other side of the structure.
■ What Is a Decibel?
Decibels are units of measurement that follow a logarithmic scale. Anything that makes sound gets measured based on the unit named after Alexander Graham Bell to measure intensity. Human hearing can get damaged when exposed to loud noises for too long, which is why understanding how much output a generator creates is essential when building a soundproof enclosure. If it doesn’t reduce levels enough, it could still be problematic for nearby individuals.
■ How Loud Does Sound Need to Be before It Becomes Dangerous?
Sound becomes dangerous once it reaches 85 decibels. Although the exposure level needed to cause damage would be several hours, it is still a painful experience for some people. As the decibels increase, the exposure time to cause injury decreases. Although most portable generators won’t produce anything in the 140 dB range, industrial equipment could – and that would require hearing protection for someone near the generator.
Are You Ready to Build a DIY Generator Sound Enclosure?
If you have a loud generator that disturbs the neighbors, a soundproof enclosure can make everyone happy while getting access to the power needed.
The steps needed to complete this process can be finished in an afternoon after securing the materials.
Some homeowners may need to check with their HOA to determine if placing a soundproof enclosure is permissible within their rules.
Once installed, you have full-time protection to reduce the sound levels emanating from the generator. Get started today if you need the help, and enjoy the quieter energy.