Garage fan vent advice


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Sep 22, 2023
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96 Cougar 4.6L
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I'd like to install some ventilation in my garage. The driving force for this was the fighting with that last lug nut on the Jeep. I soaked it in PB blaster and being my garage is connected to the house it stunk up the whole first floor something awful. I have a ceiling fan in there that's always on low for circulation, but that doesn't help drawing in fresh air.

I'd like a 2 stage fan that I can leave run on low constantly, but turn on high when stenches call for it. I was thinking of just putting in a bath fan, but was unable to find a 2 speed in my searches.

You guys got any advice? thanks.
How big is your garage? Is there a finished ceiling? Are you venting directly outside or into a plenum space of some kind?

I think most bathroom vents wouldn't have enough CFM to be effective at controlling the air quality in a room that large. Something more like this may be appropriate though, depending on your circumstances.
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For a garage, you're going to need something more substantial than a bathroom exhaust fan. At the high end, they're moving around 110 CFM, with some models I've seen going up to 160-200 through a 4" diameter duct. A heavy duty kitchen range hood that uses a 6" duct flows 1000 CFM. For the volume of a garage, you'd need a good bit more than that if you really want to get rid of odors.
25 years ago I worked residential HVAC construction. Bathroom fans are referred to as "Fart fans". They barely move air. On high dollar custom homes they would install real nice bathroom fans. Expensive stuff. Still wouldn't be what you are looking for.
Brandon and Irv are right. You need to look in a different direction.
Maybe I'm over thinking this but you might want a fan that won't ignite brake clean and PB blaster vapors passing thru it.

I have the 9155. And it works! Easy install if you have a window in the garage. I like that I can bring fresh air in as well as exhaust. This fan works so well the door will open if it's not latched due the suction.

I have the 9155. And it works! Easy install if you have a window in the garage. I like that I can bring fresh air in as well as exhaust. This fan works so well the door will open if it's not latched due the suction.
That looks like a nice option.
Single car garage, finished ceiling. There is a bonus room above the garage but the roof cover down to the garage ceiling so there is attic space that’s vented through the eve on the front and back of the garage space.

Unfortunately no windows.

Good points on the fart fans, was just thinking about getting some air flow.

I generally don’t work in the garage since it’s so tight. I have the jeep on stand to swap out the wheels and of course the very last lug nut was troublesome.
Find an old "squirrel cage" furnace fan and electric motor. Those things move air, and are mobile for where you need them. You can prop the garage door up with it and fill the other space with a 2*6 to keep rodents out. The upper part of the door becomes your cold air inlet. Not a good solution for when it's cold out... But otherwise great
A 20" window fan works pretty good, and you have to option of filtered air with 5 20x20x1 furnace filters. Works great for painting. :)
I use some old rotron 12" 220v fans I rescued from a dumpster, most of the time. 235 cfm each, they move some air!

We just installed these exhaust fans for fume hood extraction in a science building, all stainless duct. Not cheap. 😉
If the weather is nice out, I'll use this 30" whole house fan in my shop. It pulls from an open window/door and exhausts into the vented attic. Here's a shot of it from back when I was putting up the building, as all you can see now is the louvers beneath it.

fan installed.JPG

More often than not, I don't want to lose my conditioned air, so I run this scrubber. I built it with a direct drive furnace blower fan with a 10" x 8" wheel, and some odds and ends. I reuse the used 20"x20"x3.5" Merv 15 filters from our home HVAC unit and pre-filter with cheap 20"x20"x1" Merv 9 filters. It sucks up haze and fumes like mad.


IMG_8446 large.jpg
Are there any industrial equipment auctions near you? This is from a prop house downsizing their collection of junk

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