Mufflers & Silencers For Generators: What Really Works To Reduce Engine Noise

Portage generators are a great tool to have for mobile power, blackouts, and RVs.

However, they can generate a lot of noise which can prove to be a nuisance in rural areas or close quarters.

If you are like me, you want to be able to keep your noise pollution from your generator down as much as possible.

That is where a portable generator silencer or muffler comes in!

A silencer or muffler attaches to the exhaust pipe on your generator and helps to suppress the noise that is produced by the generator.

There are a number of different ways that are said to reduce the noise levels of your generator and in this post, I am going to show you what really works.

How Loud Are Generators

You know as well as I do that portable generators are loud, but just how loud are they?

Most portable generators have a noise level or 70-100 decibels at 23 feet (industry standard measuring).

Noise levels will vary depending on which make, model, and size you choose to go with – see this post about the quietest brands and models.

From my experience, if you choose to spend a little more money up front, you can get a quieter model that will require less sound muffling than cheaper models.

However, I understand that an expensive generator is not in everyone’s budget so knowing how to quiet down a louder generator may be something you need to learn.

Why Should I Silence My Generator

Silencing or muffling your generator not only helps keep you from being bothered by a constantly loud motor, but it is also a generous act for others around you.

Using a generator in a neighborhood setting can cause your neighbors to be annoyed by the constant drone of the generator and showing that you are at least trying to keep the sound down will go a long way.

For those using a generator in the winter months where snow is prevalent, keeping your generator near your home or in your garage may be necessary.

This can amplify the sound greatly and keeping it muffled can really help out. For whatever reason you may need to muffle your generator, I am going to provide you with my top tips on how to do it.

Using An Automotive Muffler

Yes, you read that right, you can use an automotive muffler to muffle the sound of your portable generator.

While this is not the easiest method when done correctly, it can be good for a 10-15 decibel reduction. All you will need is an automotive muffler, some creativity, and a few tools.

Now when I say done correctly, I am referring to those who have bent, welded, and mounted the correct piping and adapters for a leak-free exhaust.

This requires a great deal of skill, but can be done and the results are actually quite nice.

You can still achieve a reduction in noise levels by simply bolting the muffler on with some clamps and exhaust flex tubing, however, it is not as effective as welding the correct piping together.

I will say that the type of muffler that you choose will influence how much noise is reduced.

You will want to do a little research on specific muffler specs and sizes to ensure you get one that will properly muffle and will fit on your generator without being intrusive.

Using A Generator Muffler Silencer

The most popular way to correctly muffle your generator’s exhaust is with a generator muffler silencer.

These silencers mount to your portable generator’s exhaust and act as a silencer to reduce noise levels by 10-15 decibels.

They can be bought or made at home, however, you want to make sure you have a decent amount of knowledge on how mufflers and silencers work to allow for adequate exhaust flow.

Muffling Sound With Plywood Boards

One of the quickest and most inexpensive ways to reduce your generator’s decibel levels is by muffling the sounds with plywood.

By placing plywood around the generator, you can lower the noise level down at least 10 decibels, which will make it much more bearable in a neighborhood setting.

To do this, you will need some plywood scraps that are large enough to extend past your generator.

You will then lay them against your generator in a box shape to deflect the generator’s noise to the ground.

This allows for the sound to be contained and absorbed into the ground instead of toward your surroundings.

Building A Silencer Box

If you are wanting a more comprehensive solution, you can build a silencer box that installs over your generator to muffle the noise similar to the plywood method.

Building a silencer box will take a bit of wood working, but it provides you an easy way to quickly muffle the sound of your generator on the go.

To do this, you will need to build a wooden frame that fits over your portable generator and attach either plywood, foam backing, or any other sturdy material suitable for building that will muffle the sound.

Building an inner and outer box on your frame and filling it with insulation is a way to effectively reduce noise while keeping the box lightweight.

A few things to remember are to add a handle for easy handling, ensure there is adequate air flow to reduce the chances of overheating, and be sure to add a cutout for an exhaust extension to allow your generator’s exhaust to flow properly.

This will greatly reduce the changes of your generator overheating from inadequate airflow.

I have seen a few boxes with built in fans that helped cool the generator while it was running, so the possibilities are endless.

5 Tips For Keeping Noise Levels Down

While all of these methods above will help drastically improve your noise level on your generator, there are a few simple tips that you can follow to reduce noise pollution.

Install Your Generator Away From Your Home

While this seems like a no brainer, it is often a factor that is overlooked when using a portable generator.

Most generators produce 70-80 decibels at 23 feet which could be more than you are wanting to hear inside your home.

Simply moving your generator further away from your home and utilizing longer extension cords can easily cut down on how much noise you hear from your portable generator.

Keep The Exhaust Facing Away From Your Home

If moving your generator further from your home is not an option, there are still ways to keep the noise level down.

One simply trick is to have the exhaust, the main source of noise, pointed away from your home.

Sound waves travel and having them travel in a direction away from your home can make a huge difference when compared to having the exhaust pointed in the direction of your home.

Add one of the tips from above and get double the sound reduction!

See my post on how to extend a generator exhaust

Deflect The Sound As Much As Possible

Similar to the plywood method of deflecting sound, using your surroundings to help deflect the sound can be a huge help.

Simply moving items near your generator in front of or around your generator can help deflect the sound.

One of our favorite ways is to mount it behind a shed or other solid object that will help absorb sound.

Install The Generator On A Sturdy, Sound Absorbing Floor

The last thing you want to do when setting up your portable generator is to make it louder by installing it on a sound amplifying floor.

Running your generator on a concrete or wooden floor can cause the sound of your generator to be amplified louder than normal.

I suggest adding a sound absorbing mat to where your generator will be mounted in the form of a heavy duty shop mat to help reduce unnecessary noise

Invest In A High Quality Generator With Low Noise Volumes

If your budget allows for it, the easiest way to keep your noise levels down with your generator is investing in a high quality generator with a low noise output.

While this is not always an option for everyone, it is my best suggestion on having a quiet generator that requires no extra work to muffle and sounds.

In Conclusion

Taking all of these suggestions into consideration, you can easily quiet down your portable generator with any type of budget.

The main things to consider is how much time and energy you want to put into your muffler solution.

As of now, there is no solid solution to effectively silence your generator completely, but reducing it down by 10-15 decibels can make a surprisingly big difference that your neighbors will surely appreciate.

With all of these solutions, please use extreme caution on proper ventilation and adequate airflow to protect both you and your generator.

We want to hear from you! In what ways have you effectively muffled or silenced your generator?

What products have worked and not worked for your generator?

7 thoughts on “Mufflers & Silencers For Generators: What Really Works To Reduce Engine Noise”

  1. Hi how are you? nice post. I have some question… i need to buy a Champions 12000 Watts for my food truck and I think (78 dB). So the question is if this whole system muffler+silencer+zoombie box could help me to decrease the noise
    Thanks

    Reply
    • I have a Cummins stand by generator that runs at 3600 RPMs. It’s mounted on a slab. Any ideas to reduce the noise other than building a wall?

      Many Thanks – Ed

      Reply
  2. It seems the noise from my XG-SF600 (500W, real Sinus, 4 stroke, ~20 pounds, ~9Kg, official ~58dB, similar to Honda “EU10i” but smaller) does not come from the small muffler.
    With a water hose on muffler output, and outside the door, the noise is not lower.

    Do you have any advice what I could do?
    A complete box of 2.5cm thick compressed wood and inside bitumen tiles and 3cm sound absorbing foam (I have bitumen with foam on it)?
    But the air supply.
    Every hole for a fan is an exit for noise.
    Should I put an old automobile exhaust in the wood case? But then I have to press or suck the air through the exhaust.
    And the openings on an exhaust are very small.
    One fan has 8cm, 12cm, 15cm (I have two old 35W-230V ~ 6-inch, ~ 15cm fans from Pabst).

    Do not I need two mufflers? One for the air outlet, and one for the air intake?

    Reply
  3. I spoke to a generator specialist and he said that a box, even well ventilated, will dramatically shorten the gens life due to the high temp and recirculating emmisions. What do yo guys here think?

    Reply
    • I’m on the fence on this, if you use passive ventilation you might not get rid of all the heat, but if you have active ventilation in the form of a fan you shouldn’t have any issues at all, infact you can more then likely run the generator cooler if you do it correctly, and you can also incorporate air intake filters using a MERV10 or higher furnace filter and you’ll keep everything cleaner which will also help increase the life of your generator, but again there is a cost to doing this, adding a fan adds a load to the generator which is fuel, but if it’s done correctly they can be very nice and quite and keep your unit out of the elements and dry.

      Reply
  4. I think that all the ideas are great and just shows I’m not the only creative person with this problem of generator sound. I am going to build an insulated box by sandwiching both plywood and foam set about 12” in ground on concrete pad with shop mat beneath adding a lock down system for theft finishing with a silencer or muffler and a 12” automotive fan with a 12 volt battery and a solar charging system to keep battery charged and generator cool Maintenance is to use an extractor to change oil The entire cost with generator is $873.00

    Reply
    • I like your idea, but those automotive fans use several amps while running and will kill the battery fairly quickly, If I was to do what your doing I would also grab a small HP server power supply like a DPS800-GB ( they are like $20 on ebay ) and use this to charge the battery from the generator while it’s running or at least to maintain the fan, they are small power supplies they run on any voltage between 100 and 240 VAC 47 Hz to 63 Hz they don’t care if your not using a newer inverter generator and they will output about 80 Amps at 12 volts, a quick google search will show you how to make them work, and some of the radio amatures will even tell you how to increase the output voltage to 13.6 to 14.1 DC to use them as very nice battery chargers on the cheap. I have two of them and they are the size of a 1 quart milk carton and only weight like 2 maybe 3 lbs and they will recharge a group 21 in about an hour and will keep your fan moving all night long.

      Reply

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