Home>Discussions>INSULATION & HVAC>attic fan in post and beam structure
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allen wood works
attic fan in post and beam structure

i have a question that i cant get a straight answer on if anyone knows..
in regards to my 'attic fan' in my pre war post and beam shop. my building is an old post and beam style with no drop ceiling, just exposed and completely uninsulated 2" x 8" t&g roof sheathing. I have a rather large attic fan near the ridge which is 20' from the floor. The fan is off to one side, the opposite side that my huge window unit is on, building is approx 25 x 40.
i have been told by a few friends that i need to keep the attic fan on all the time when its hot outside, drawing the hot air out from the top of the room and keeping it from creeping down to the cooler air below. so is this right? makes good sense but then again makes sense that it's drawing hot air out and allowing cool air to rise and leave with it.
i know insulation is my best and only real choice but its a rented commercial building with a 5 year lease and i have zero interest in spending 4 grand to upfit someones building with spray foam or any other method.
so whats the consensus here?
also i have 2 more fans that an electrician buddy gave me that i could install one or both of in the ceiling nearer to the ac unit if this is a good idea.
whatever it takes at this point as yesterday got to 93 and the shop crept up towards 84 inside even with AC running full blast all day, obviously i would love to get that closer to 75!
thanks for the suggestions everyone.

Re: attic fan in post and beam structure

in my opinion there's no use in running the fan if there isn't a way for it to pull in fresh air. obviously if the window on the other side of the roof is open then the fan will be doing it's job properly. if the fan is running continuously and the building is sealed up tight then barely any air is being expelled. if regular wall windows are opened and the fan is turned on then the fan is pulling fresh air in from below and expelling hot air which sits at the peak of the roofline.

allen wood works
Re: attic fan in post and beam structure

makes perfect sense, thanks!
funny as i had previously envisioned a 'fresh air intake' that i could easily rig up with a squirrel cage fan mounted in the crawlspace pulling cool air in. The crawlspace under the building never gets above 80 or so even on the absolute hottest of days.
does this seem logical as an added way to get cool air in/expel roof line hot air without sucking all of my conditioned air right out of the building?

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