Cupola exhaust fans?

Now I need cupola exhaust fans to fit in a 34" x 34" rough-in space.

They need to sit horizontally (so maybe all the gable or wall ones work, maybe they don’t?)

As many CFM as possible… and as quiet as possible.

The barns I have been in have a switch, but then also a thermostatic control so that when the fan is “on” it’s actually only on if the temperature rises above a certain level.

Some kind of grille on the lower side to keep birds out.

Anyone have any recommendations? I’m not finding the obviously right kind of fan at places like FarmTek or Grainger or Global Industrial.

Thanks!

I have a couple thoughts.
Did you see this thread from the past?:

I’m not seeing anything online that is a grilled fan to sit flat like that. What if you built a frame and mounted a closed motor fan and you would install a removable grill on the bottom for annual cleaning.

We have a house fan in our aisleway ceiling and it is simply amazing how much it cools the house in the summer. We barely need AC - however do have woods sitting behind us so the house goes in the shade by 5pm every day and that is huge.

I see big advantage to your cupola fan idea.

Thanks! I did see that thread. Sadly, there was no definitive plug-n-play recommendation that quite answered all my questions.

Just re-opening the topic in case someone since had figured this out.

ETA: And, yes, exhaust fans in the cupolas can help, appreciably. I live in the hot-n-humid Southeast and I worked in a barn one summer that had a fan in its cupola. You could feel the air being drawn past you in the aisle. It was a nice addition to the stall fans, plus easier to work around than a big, rolling drum fan.

And this barn is next to a line of trees to the West, so it does benefit from shade coming over it early-ish. But my goal with this whole building is to make it as cool and bug free as I can… or as I can afford to.

Have you looked at a manufacturer’s site to see what they recommend? Someplace that aims at dairy, poultry, greenhouses, etc. Rather than a re-seller, like FarmTek.

For instance J & D:

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Attic fans may help?
They come in all kinds and sizes:

https://www.google.com/search?client=safari&rls=en&q=Attic+fans&ie=UTF-8&oe=UTF-8

Ask an electric company, they will know what may work.

A friend put one of those about 3’ large ones high on the gable of his horse barn where there was a window.
It drew a nice airflow between front door and fan, all along the aisle, door under fan closed or open.

Might sound funny, but restaurant venting fan might be an idea. They vent upward up thru the roof, though I am not sure of the fan location or it’s mounted direction of horizontal or upright.

At 34" square, your best best is probably one of these 24" fans.

https://www.industrialfansdirect.com/collections/agriculture-box-fans

Are you early enough in the building process that you can resize your space to 36" x 36"?

ETA: the rough in on the 24" fans is actually 30"x30" so you’re not losing much.

if done I would include a auto shutoff switch that would detect a rise in heat, a fire shutoff switch

I think google suggested those, but they usually have flat, mushroom-looking caps on them. I think I need a more straight-forward fan as these will go inside a cupola that has louvers in it.

Yup, the 24" looks right. The fans I have known had thermostats built in somewhere. I don’t see any exhaust fans that have that, so I wonder if those are put somewhere else in the wiring between the fan and switch.

These cupolas are wired for fans and lightning rod protection. I just have to find the right fan, get my builder to install it… and hope that I never, ever have to go up there again. This barn roof his high and I think you’d need a scaffold to get up there.

The thermostat is sold separately, but it’s linked on the same page

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Hey, who is the vendor for this? I can’t find the thermostat on the same page if I find this fan at Global Industrial.

Also, in the specs, it’s rated for indoors (though it’s sold as an ag fan). To me, a cupola with louvers on it might be “indoors” enough, but I don’t know.

I’m not sure I understand your question. The screenshot is the 24" fan I linked above. Here’s the direct link to the thermostat.

I have this in my barn ceiling. It’s on a switch, kind of loud, but works great:

Cool Attic CX24DDWT Direct Drive 2-Speed Whole House Attic Fan with Shutter, 24 Inch https://a.co/d/4GjZ6w0

In practice does a cupola really work that much better than have a continuous ridge vent? Just curious.