# Generator shed challenges?



## jeb (Feb 16, 2021)

Hi Folks,

For years, I've just garaged my portable 15KW generator and wheeled it outside when needed. This of course keeps the generator in a dry, insulated environment. 

I really need to get the space back in the garage...so contemplating pouring a concrete pad and either building a cover with ventilation(fan) and plumbing exhaust out...or just buying a pre-manufactured one like they have on Generator Enclosures | Soundproof Generator Sheds for example.


My question to folks that have done this:

1. Since you now have your genset outside in a non-heated, insulated environment, have you found more issues with maintenance such as corrosion?

Since the shed and cover will block rain/snow, etc. its not those directly hitting the generator that I'm concerned about...but more about the general air humidity that I'm concerned about.

2. Any issues with critters including ants, etc? Vents have screens...but ants and other small pests are necessarily blocked by the screens.
Maybe preemptively using granule pesticide around the genset would alleviate that.


Any other issues you've had to deal with?

Any feedback and personal experience would be apprecaited.

Thanks.

-J


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## exmar (Jun 29, 2015)

JMHO, buy it from Generac, everything fits, airflow and exhaust issues already addressed, and whatever they charge it'll probably be cheaper than imagineering and tinkering together something. Something else to consider, if there's a fire or other loss, your insurance company might be more forgiving of a packaged product rather than a DIY.


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## Old man here (Nov 5, 2020)

exmar said:


> JMHO, buy it from Generac, everything fits, airflow and exhaust issues already addressed, and whatever they charge it'll probably be cheaper than imagineering and tinkering together something. Something else to consider, if there's a fire or other loss, your insurance company might be more forgiving of a packaged product rather than a DIY.


Generac doesn't make enclosures for the portable generators unfortunately.
The price of those enclosures the OP linked to are out of this world.
As far as storage, I have a 12'x12' unheated shed I store mine in, no issues with corrosion, bugs, or mice.


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## jeb (Feb 16, 2021)

Old man here said:


> Generac doesn't make enclosures for the portable generators unfortunately.
> The price of those enclosures the OP linked to are out of this world.
> As far as storage, I have a 12'x12' unheated shed I store mine in, no issues with corrosion, bugs, or mice.


I actually thought I could build something like that myself and using a fan for airflow - similar to that setup. Yes, the cost is crazy with those boxes..but they sure look well made. I like the idea of being modular for easier maintenance of the genset if I have to get in there to do work.


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## Browse Deweb (Jan 16, 2021)

jeb said:


> I actually thought I could build something like that myself and using a fan for airflow - similar to that setup. Yes, the cost is crazy with those boxes..but they sure look well made. I like the idea of being modular for easier maintenance of the genset if I have to get in there to do work.


The enclosure in the video seems like it should cost around $500. To pay $1500-$2000 for that seems wasteful. I keep my generator in the garage and I like the fact that it isn't subject to temperature and humidity extremes. Mine also doesn't require sound dampening when running...it's super quiet. I can hear my neighbors generators before I can hear mine.


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## Old man here (Nov 5, 2020)

jeb said:


> I actually thought I could build something like that myself and using a fan for airflow - similar to that setup. Yes, the cost is crazy with those boxes..but they sure look well made. I like the idea of being modular for easier maintenance of the genset if I have to get in there to do work.


My main concern would be excessive heat inside the box. I also have the 15KW Generac.
My shed has an 8ft. wide door and a 24" vent fan, 2ea. 2'x2' windows, and vented eaves.
I run my generator with it setting several feet back from the door with a 6' long 1 1/2" dia. flex pipe exhaust extension. Of course I have two CO2 monitors in the shed.
It gets pretty warm in the shed from the heat produced by that big engine and generator head.


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## jeb (Feb 16, 2021)

So, if I have a 30HP motor which is equivalent to 76,333 BTU/hr, I'm assuming as long as I have enough airflow to push that out of the shed, I should be fine for heat? Not all of that is heat...but if I want to figure worst case scenario if I was generating all heat that is what I would need to move that out of the shed. I think the conversion to CFM is ~164BTU per 1CFM. So that means I'd need 465CFM (worst case) of airflow to move that heat. Again...that is no way near what I need...its just if the generator was a full on heater. Most attic fans can move 800+ CFM...so I'd imagine that would cover me...which is why it looks like those Zombie boxes are just using a glorified Attic fan for their air flow.


Again...this is all on paper and the crazy things I'm thinking about since I've been out of power for 6 days and running on generator power 


-J


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## Old man here (Nov 5, 2020)

jeb said:


> So, if I have a 30HP motor which is equivalent to 76,333 BTU/hr, I'm assuming as long as I have enough airflow to push that out of the shed, I should be fine for heat? Not all of that is heat...but if I want to figure worst case scenario if I was generating all heat that is what I would need to move that out of the shed. I think the conversion to CFM is ~164BTU per 1CFM. So that means I'd need 465CFM (worst case) of airflow to move that heat. Again...that is no way near what I need...its just if the generator was a full on heater. Most attic fans can move 800+ CFM...so I'd imagine that would cover me...which is why it looks like those Zombie boxes are just using a glorified Attic fan for their air flow.
> 
> 
> Again...this is all on paper and the crazy things I'm thinking about since I've been out of power for 6 days and running on generator power
> ...


Jeb,
I applaud you for digging in and doing all of those calculations! I have no doubt that proper air exchange and air flow cannot be achieved in one of those enclosures. 
Look at the Generac enclosures for their standby generators. Apparently they work and allow the generators to operate in any climate, without regards to outdoor temps. 
The only thing I would want would be to have some way to monitor the temp in the enclosure while the generator is running.
I think it's about time we all get a break and a trip to somewhere warm, have a few beers and say "wow glad that's all over for awhile".


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## Ground Fault (Jun 9, 2020)

Or, _if you have the space_, consider building another garage/mancave with dedicated space for a separate utility room containing your generator and all ancillary equipment for it. Store and run it from there, stay out there most of the time and enjoy your life, and tell her you are working on the generator. I've got one, that's what I do, _and I STILL want that Zombie box..._


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## tabora (Sep 6, 2018)

Build one... This was an afternoon project.

I used a SunCast BMS2500 shed with a 16" 1,200CFM iLiving ILG8SF16V Exhaust Fan on the right side; the generator is turned so that the exhaust faces the bottom of the fan and exhausts with the airflow. There is a 17" 5NKN4 Dayton gravity operated inlet shutter on the left side. I have a thermal remote monitor mounted top center on rear wall, and a second one mounted outside on the propane tank. The internal alarm is set at 80F and has never gone off in 3 years of operation (about 60 running hours so far).


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## Bluwolf (Nov 8, 2020)

I did something very similar to tabora. But I started with the Suncast BMS4700. It allowed me to put 2-40 lb. propane tanks in the shed with the generator and store my empty 5 gal gas tanks in there as well. Even though it's never had gas in it. I will not run gas in the generator unless I absolutely have to. When the generator is running the gas cans and the shelf pop out. I have an RV automatic switchover set up for the propane tanks.









The shed has a large vent on the left end and an attic fan on the right side. There are also 2 vents up high on the doors. They all have noseeum (tiny little biting gnats) screen behind them. The noseeums are everywhere here in SW Florida. It's very common for all the pool enclosures to use them on the sides of the enclosures. The screening is a much smaller hole size. I also caulked all around the vents to fill in all the fake siding gaps.



















I bought custom screen window kits to make the screens to fit all the vents. They're easy to build and work great.



















If I didn't have dogs I would do what you suggested and use the granules around the shed. Instead, I just use the liquid insect spray around the inside perimeter. I also put a tarp over the shed to keep the sun off it. The sun is brutal down here along with the heat. Which means we have insects and critters year round even in the "winter". With this setup the shed, inside and out, looks as new as the day I built it.

You can buy kits for all the stuff to go in the sheds here. I didn't, but you could if you wanted one stop shopping.

PowerShelter Kit II - for storing and running portable generator inside a shed

They also have something similar to the zombie boxes, but seem much less expensive. It says they're out of production right now. But they're only $999. There is also a bigger one for $1499. They look pretty nice and still cheaper than the zombie boxes.

Powershelter III
PowerShelter III - enclosure for storing and running portable generator

Mike


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## jeb (Feb 16, 2021)

Cool. Thanks for sharing the info.
Looks like I have some options.


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