Quieting noisy generator?

My elderly parents have a Generac (12 kW, I think), fueled by natural gas,
for emergency backup. Weekly self-tests and occasional real use are
upsetting to them due to the high noise level. Re-siting is not an option,
and simple baffling with boards leaned against the metal case doesn't make
much difference.

Store and installer were no help. Dos anyone know if it's practical to add a
much bigger muffler to these units? Aside from warranty issues, are there
any concerns for safety, damage to engine, etc?

Also, I'm not sure where the noise actually originates - only a part sounds
like engine note; the rest is like white noise. So I may instead build a box
with plenty of colling clearance, with one open side pointing away from the
house, lined with heavy acoustic foam.

Thanks in advance for useful ideas-

DM

 

All of the generacs I have dealt with were loud. Both engine and exhaust.
I would think once you found the specs on the muffler you could reduce the
db there fairly easily. One method might be just pipe the exhaust away from
the home. Make sure you use a larger pipe than what is there by 2-3 sizes
depending on how far your going and how many bends are made.

I have seen enclosures that limit the sound from gensets. I bet if you made
one with plenty of air flow and space. You could put fiber glass insulation
inside of it and reduce the noise.
How much these measures will work will be dependant on how well you do
them. Quality counts.

 

I built an enclosure for my pad-mounted Onan that works very well. My
generator came in a steel box with a screen at one end to suck in cooling
and intake air, the hot air and exhaust streams are mixed together and blow
out a square hole on the side. I built a stout wooden 6' fence around the
generator using two layers of pressure treated 3/4" fence pickets with a
tight fitting gate for access. The fence goes all of the way to the ground
and is sealed in and out with wooden mulch. An airtight plenum allows the
generator fan to suck in fresh air; the hot air and exhaust just fill up
inside the fence and escapes upwards. A soft canvas peaked roof made from a
cheap tarp completes the deal. I find that this system is good for at least
10 db of noise reduction. In addition, it offers protection from hurricane
debris and unauthorized humans. Sound escaping is quite directional, and,
not surprisingly, is loudest in the direction of the plenum. Future
enhancements may include a baffle in front of that plenum and some type of a
noise-baffling roof. Mine operates from LP gas and I have a separate
(hopefully cooler) enclosure for the tanks.

Vaughn

 

Mass cuts the noise considerably. Build a masonry wall between the genny and
the house and any neighbors you want to reduce the noise. An open top will
direct the noise up and away from people.
Light materials such as wood don't work as well, the more mass the better.

 

Mass cuts the noise considerably. Build a masonry wall between the genny and
the house and any neighbors you want to reduce the noise. An open top will
direct the noise up and away from people.
Light materials such as wood don't work as well, the more mass the better.