I built an air tight super insulated house, and needed my bathroom fan
on all night for air exchange [I know, I never got around to building
the heat exchangers because we started having kids.].
I had the super quiet mode fan, but I wanted lower flow and even lower
noise.
I got a dimmer switch that was rated for motors.
That way I could dial in the noise and air flow I wanted.

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A society that teaches evolution as fact will breed a generation of atheists that will destroy the society. It is Darwinian.