Undersized vent fan - good for anything?

[JHZR2]

My one garage building has a 1000sf loft, no roof insulation, but it does have a ridge vent. The building is leaky, it is not climate controlled or sealed in any way.

In the last heat wave, it was super hot up there. Natural ventilation via the ridge vent wasn’t sufficient. Metal tools on the loft were hot to the touch, too hot to comfortably hold, and this was well into the evening after the sun wasn’t as strong.

So that brings me to airflow. Because of some work I did on the building, I have a few 3” holes through the upper walls.

This my idea - the $21 50CFM vent fan. I could install 1-4 of them, let’s say, and flow up to say 200cfm.

Sure there are much more expensive fans available, and of course ceiling fans or similar could also be used. But the $21 vent fan is… $21.

Yeah, I get it that it isn’t 5-6 air changes per hour, or 1cfm per sf, which are rules of thumb that I’ve seen.

But if I want to induce some air exchange to manage the heat levels in there under hot summer conditions, would this make sense?

Yes, I could put a box fan in a window. Blowing in, out, or through. But then I have wide open windows with fans in th. Not great when 4” of rain shows in an hour like we had yesterday…

Thoughts? Exercise in futility?

 

[dishdude]

That's like emptying the ocean with a teaspoon. Get a real attic fan or don't bother, those cheap 50 CFM fans can't even keep a small bathroom dry.

 

[Pablo]

That's like emptying the ocean with a teaspoon. Get a real attic fan or don't bother, those cheap 50 CFM fans can't even keep a small bathroom dry.

This.

 

[JohnnyG]

That's like emptying the ocean with a teaspoon. Get a real attic fan or don't bother, those cheap 50 CFM fans can't even keep a small bathroom dry.

Right.
Maybe just a good whole house fan, but I see they are much more expensive.
$279.00 @ Lowe's

https://www.lowes.com/pd/Cool-Attic...MI9p2hvPHAlQMVZIrCCB33sjNJEAQYBSABEgIE4PD_BwE

 

[AZjeff]

Less than 4 of your $21 fans and moves 2338 CFM. You need to draw replacement air from somewhere.


https://www.homedepot.com/pep/iLIVI...exDwHMc_8Yng3Jg370zxIkJqnSSamtpBoCr-EQAvD_BwE

 

[JHZR2]

That's like emptying the ocean with a teaspoon. Get a real attic fan or don't bother, those cheap 50 CFM fans can't even keep a small bathroom dry.

Problem with that logic is that when I put a 1700 cfm box fan on the window it stayed hot. Too much latent heat.

The key would be to just have it on a timer or run it continuously in advance to not let it get as bad as it was. But that said, perfect is the enemy of good enough.

Don’t really want/need to spend a ton, since it’s typically closed and unoccupied, and has been fine for over 100 years.

 

[dishdude]

I was thinking something more like this.

https://www.lowes.com/pd/Air-Vent-1...zed-Steel-Electric-Power-Roof-Vent/1000402231

 

[JHZR2]

You need to draw replacement air from somewhere.

The building is porous.

 

[JHZR2]

I was thinking something more like this.

https://www.lowes.com/pd/Air-Vent-1...zed-Steel-Electric-Power-Roof-Vent/1000402231

Hindsight is 20/20 I just did my roof and should have had one installed.

 

[Nukeman7]

My friend installed one of these through-the-wall fans near the peak of the gable end in his 20' x 16' stand alone un-insulated garage. It made a huge difference in the ambient temperature during the summer months.

iLIVING 18" Wall Exhaust Fan

 

[spasm3]

If its that hot, i don't think 200 cfm is going to do much of anything.

I would think about this.

https://a.co/d/00W3LG1e

 

[IndyIan]

If its that hot, i don't think 200 cfm is going to do much of anything.

I would think about this.

https://a.co/d/00W3LG1e

One of those in the peak of the roof should move a lot of air.
Is there lots of exposed steel roof on the interior side? I think with a steel roof, the thermal radiation from exposed steel will still heat up items in your attic. Maybe try a section of roof rafter channels, then the ridge vents will work better and there's much less thermal radiation too? Or just tack a roll of house wrap across all the rafters, might be cheaper and faster than rafter channels?