I'm planning to use an inline fan for a range hood - I'm going to have the
canopy made by a metal fabricator. I'm putting the fan in the attic.
I'm looking for something

- about 300 CFM max
- can be speed controlled about all the way to 0.
- doesn't make a hum or whatever when speed controlled.
- Absolutely as quiet as possible.

I've heard that if you compare a small fan with a large fan that's turned
down with a speed control to move the same CFM as the small fan, the large
fan will be quieter.

Somebody at Fantech told me this wasn't true, that the noise just depends
on the CFM the fan is moving. I don't believe this (she said other very
dubious things), because I've heard elsewhere that a larger fan will be moving
with a lower RPM when it's moving the same amount of air, so it would be
quieter.

So, I figure I'd get about a 300 CFM fan and turn it down with a speed
control. My range is very small and it doesn't need a big fan.

Some fans make a low-voltage hum when you use a speed control on them.
Fantech said their fans do. Someone at Broan told me their inline duct
fan doesn't have a low-voltage hum when speed controlled. I don't know how big
of a deal the low-voltage hum is, compared to the noise from the fan
motor.

What inline fans are quietest? They don't have a standard way of testing
the noise from them, unfortunately.

I know stuff about reducing the noise that's moving through the duct -
duct silencer, liquid soundproofing you can spray inside the duct. Etc.
etc. My question though is about the quietest *fan*.

Laura