Billy_Big_Bud

i was wondering if some one could help me with a fan question? my room is about 50 cubic feet and my fan is 65cfm. i recently moved the fan from an intake to an exaust leaving a hole the same size as the fan which now has created a suction through the hole for fresh air. my question: is the hole which is the same size as the fan, a big enough intake hole? they are both 4" should the intake hole be any bigger?

highonline

High Bud.!

Well, i see no problem with this, i have a 300 cfm fan on a 4 inch pipe, as long as it's not whistling you are fine, you can't expell more air than you are pullin in, so.

You generaly want your intake bigger than your exaust, but the same size is still not a problem.

highonline.

gramma

Highonline

what would make it whistle?

if the intake hole is big enough would it handle any kind of a real strong exhaust fan without having a suck fan at the intake hole? just a big square hole with screen on it so no bugs can get in. am still trying to learn all i can.

gramma

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gramma

highonline

Got your e-mail gramma, sorry for not replying sooner, been busy these days!!

The reason you might get a whisle is if your fan sucks more air volume than what the pipe can permit, you will get a hum. just like when you put your hand on the end of a vaccum cleaner pipe, the motor whines and you get a higher pitch ( or more noise ) because the motor encounters some resistance making it work harder.

This is not an exact analogy but your get the idea!

You could have a 2 inch fan on a 4 inch pipe with no problem but try running a 2 inch pipe on a 4 inch fan and you'll understand. If you fan is mounted directly on the inlet/outlet and you do not have any piping involved then you are fine unless you have like a million cfm ( cubic foot per minute ) fan!

To answer you question, yes, you can run a fan on your exhause withour having one on the intake, no prob!

highonline.