Here's a pic of what I use to dial down the fan speed. It's called Dial-A-Temp, and if I recall correctly, it's used generally to dial down the fan speed on fireplace fans and such. I can't remember where I got it, but it was online somewhere, and wasn't expensive. I got a fan speed controller when I bought the fan too (the fan's an Eco Plus 6" 440 CFM fan), but wasn't sure enough about the wiring involved, so I looked for a simpler alternative and Dial-A-Temp was it. The plug in the bottom of it, that's where the fan is plugged in.