Barn fan part 2...cfm ?s...

[Fuddy1952]

I'm removing my new but defective horse barn cupola mounted fan tomorrow and found this squirrel cage one I had. It's old but I lubed motor and fan bearings and it runs great. Opening is 14"X16" (exhaust). It seems powerful, bench running blowing stuff around the garage. Heavy...it was in loft above 2nd story, I got it down by myself.
GE motor is 1/3 hp.
Any guess how it compares to the 36" square direct drive whole house blade fan?
They're both about same 5.4 vs 5.5 amp 120v. Neither fan gives cfm. This one I'd use plywood to cover 3ft opening, cut open for this fan. Thanks.

 

[ponytug]

Efficiency is everything. My WAG would be that the newer direct drive would move more air than a squirrel cage fan that are designed to move air at a higher pressure (and thus wasted if all you are doing is exhausting the air). However, there are direct drives with lousy fan blades, poor motors, and badly designed louvers...

As an example, the radiator fan for my tractor comes in three versions that range in cfm volume by nearly a factor of three, but only a factor of two in power, so yes, one of the fans draws only slightly more than the other two, but moves nearly 100% more air than the middle range fan.

All the best,

Peter

 

[WM75Guy]

I not so sure you will be happy with it. My Morton stables has a 18" 4220 CFM fan in the cupola. It is variable speed. From a quick search it looks like a 1/3 HP motor on a squirrel cage that would be common for a 2-ton HVAC unit would put out 800-1000 CFM. And that is a newer direct drive unit.