Power consumption of fan controlled by dimmer

fan speed is controlled by dimmer ,..does it save power when it is rotating at lower speed or it consume same power as running in full speed??
i think when the speed is slow the potentiometer dissipate more power ??
plz correct me....

Re: dimmer??

I think at low-speeds, resistance to flow of current in circuit is more. So the power used is same in all cases. When speed is slow, excess power is converted into heat via resistance.

BUT I AM NOT SURE ON THIS ! Pls verify from some reliable source.

i think it depends on the circuit, if you are using a resistive potentiometer for varying the voltage to the fan then the consumption may be the same at high and at low speeds.