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Generac Air Cooled Generators Troubleshooting Questions, Answers, and Information About Air Cooled Guardian Generators

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Old July 12th, 2011   #1
DanMay
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Default Generac Guardian 14kW noise reduction

I have a Generac Guardian 14kw system installed in my home. It has been working perfect for days at a time during power outages this summer. However, the noise level is bothering the neighbors. What are my options to reduce the generator noise ?


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Old July 12th, 2011   #2
SkipD
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Without knowing the precise model of your generator, nobody can suggest any possible modifications to the generator itself.

Can you illustrate how/where the generator is installed relative to your home and to surrounding neighbors who are offended by the noise? We need to understand how the sound is being directed by reflective walls, etc. Approximate distances between buildings, heights of the buildings, terrain, any natural barriers such as trees or bushes, and any similar information is important for us to understand.

If you can sketch the immediate neighborhood roughly to scale and scan it into a digital image then you could attach that to your reply. Photographs could also help.

The first thing that comes to mind as a generic sound barrier would be a suitable set of walls with sound deadening insulation on the generator side. The idea is to aim the sound straight up rather than sideways toward the neighbors. There are many details that would have to be dealt with, though, making this a real engineering problem. You cannot have the walls closer than 3 feet on any side and they should be fire resistant. You will need two fresh air intakes - one for the engine and the other to cool the generator. It is critical that the generator is kept cool, so air flow control is a major issue.

Are the neighbors concerned with the noise at any time of day or only while they may be trying to sleep? If it's the second issue, can you do without power during the time that folks would be trying to sleep? That may be the simplest way to solve the problem.

I guess I'm kind of lucky that I live in a rural area with typically more than 150 feet between adjacent homes. I also have a line of dense evergreen trees between our home and the neighbor on the side where the generator is located.
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Old July 12th, 2011   #3
Canada_Guy
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A couple of long extension cords can help. Often neighbors are less critical if you offer them basic power that they can run their TV and a few table lamps.

You may want to plant some thick vegetation around the generator (leave sufficient space to allow heat for proper cooling/generator access). The vegetation will help absorb sound.

I wonder if there are some type of sound barrier panels that are suitable for all-weather installation?
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Old July 13th, 2011   #4
DanMay
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Default Generac Guardian 14kW noise reduction

Thanks Skip. The model is a Generac Guardian 14kw (http://www.generac.com/Guardian_Series_14_kW/). The spec sheet says the operational dB is 66 (Sound output in dB(A) at 23 ft. with generator operating at normal load). I live in a residential area, so there is about 30 feet between my generator and the neighbors bedroom window. In the summer, when we have an outage, they of course open windows and the noise bothers them.

I am working with them, and they are understanding. I just wanted to see what options others have used.

The generator is installed per code about 10 feet from a wall of my house, perpendicular so the exhaust is facing the neighbor’s house (and window). The is no vegetation or trees between us.

I have researched this a bit, and I think I have a few options.

1. Try to reduce the exhaust noise and engine noise from the generator itself. Has anyone found any luck using a quieter aftermarket muffler ?
Is there better soundproofing material or insulation that can replace what is on the inside of the generator cover/housing ?

2. Reposition the generator so the exhaust points away from the neighbor’s house. I am not sure how much that changes the noise level from their perspective.

3. Using think landscaping (evergreen bushes or shrubs) to absorb some of the sound.

4. Try to build an acoustic fence like this: http://info.acoustiblok.com/acoustiblok-products/

Daniel

P.S. I have offered an extension cord. It softened the situation, but we are both looking for a better long term solution. Since the power transfer is automatic, I really do not control when it runs. I would rather not selectively shut it off at night. That defeats the purpose of having it in the first place.
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Old July 13th, 2011   #5
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Quote:
Originally Posted by DanMay View Post
I have researched this a bit, and I think I have a few options.

1. Try to reduce the exhaust noise and engine noise from the generator itself. Has anyone found any luck using a quieter aftermarket muffler ?
Is there better soundproofing material or insulation that can replace what is on the inside of the generator cover/housing ?

2. Reposition the generator so the exhaust points away from the neighbor’s house. I am not sure how much that changes the noise level from their perspective.

3. Using think landscaping (evergreen bushes or shrubs) to absorb some of the sound.

4. Try to build an acoustic fence like this: http://info.acoustiblok.com/acoustiblok-products/
Daniel, the model number of your unit is probably 005884-0 based on the spec sheet. Look at the model/serial tag inside the unit to confirm that. If you are ever asking about specifics, that would be important.

Regarding your options list:

#1 - I seriously doubt that you'd ever find a third-party replacement muffler. In addition, adding any back-pressure on the engine may affect its operation. Thus, I'd forget this option.

#2 - If you can rotate the generator 90° so that the end where the exhaust exits the generator points away from the neighbor (as long as it does not point toward a reflective surface that would make the sound again go their way), that would be a definite improvement. As I walk around my generator (I have some very wide open space around it), the sound level is significantly greater in one direction than another. This would be the cheapest and probably the simplest to employ of your four choices and still could be quite effective.

#3 - This would be good but there are two problems. It takes a while for vegetation to grow. Vegetation does not perform the same sound-deadening effect all year round.

#4 - This type of solution may be the best option to pursue. Just make sure that there is plenty of clearance around the generator so that it won't tend to overheat. One possible down side is appearance.

I just came up with another idea, though it would be somewhat complicated to employ. You could build (if local codes would allow it) a fire-proof building around the generator. There would have to be at least three feet of space on each side of the generator and four feet above it. You would probably have to have a forced air supply (for both combustion and cooling) as well as an exhaust stack. The net result, though, is that you could contain almost all of the sound of the generator and drive it up the stack with the exhausted air. The building could be built in a way that it could be disassembled (either partly or completely) if you ever needed to get more access to the generator.

If you could sketch the area involved, we might be able to come up with some even better ideas.
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Old July 13th, 2011   #6
DanMay
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Default Generac Guardian 14kW noise reduction

Attached you will see pictures of the installation. I measure the dB 15 feet in front versus 15 feet from the side and there was a 4 dB difference (80 vs 84), so for sure I will turn it away from the neighbors house. Next, I will look at some foliage or a sound wall to absorb the noise.





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Old July 13th, 2011   #7
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Dan: Inform the neighbors about Ziller and or your installer, so they can buy their own generator, so they can close their windows and have a/c when the utility power fails.
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Old July 14th, 2011   #8
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You may be able to improve the sound deadening of the enclosure by replacing the original foam with some sound deadening foam that has a layer of mass loaded vinyl attached to it.

Not cheap, and while I've heard the stuff works very well I've never used it so I can't say how good a job it will do.
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Old July 18th, 2011   #9
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One option for 9 months of the year when A/C isn't necessary overnight, is to install a battery bank and inverter. I did that after installing my Generac so I can keep many things running overnight w/o running the genset. You get your best efficiency when its loaded near 100% so recharging a battery bank while it runs saves you money. I only have to run mine 8 hours per day for long outages - and most short outages I don't have to run it at all.

I will be converting my A/C systems to mini-split systems soon, and then I can keep 1 or 2 rooms cool overnight from the battery bank, so that will cover the other 3 months of the year. A 9000 btu unit only uses 260 watts on low, easily handled by a decently sized battery bank for 8-9 hours. But, you need to plan on spending $2500 for a mini-split, installed, and about that much again for batteries and an inverter. If you are interested look up "mitsubishi mini-split 26 seer".

Or, offer to buy your neighbor a window unit that they can keep in their bedroom closet and run from the extension cord you've offered.

Last edited by techntrek : July 18th, 2011 at 03:14 PM.
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Old July 18th, 2011   #10
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If it were mine I'd erect a sound deadning wall between the neighbors and the unit and a vertical exaust and muffler similar to an 18 wheeler to direct the exaust noise upward. A two and a half to three inch, three direction change muffler would significantly reduce the exaust noise without increasing backpressure. Install an exaust 'raincap' on top which swings up toward the neighbors to keep the rain out.
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