Temperature speed fan controller?

There are a number of options. The most simple would probably be something like this.

I use this, which controls both a heater/cooler and a humidifier, though I find the humidifier is only rarely used.

Neither of these slow or speed fans, they just turn them on or off depending on temps. I have seen inline valves that gradually open or close based on desired temps but it involved a more complex setup. They're used for rooms hooked up to a central system that need finer tuning.

 

I don't think so....at least not that I know of. You could wire up a switch through a thermostat and get your fan to come on when it gets hot, but I don't know of anything to handle the speed of the fan to cover the heat. Doesn't mean it doesn't exist....maybe I just have never heard of it. LOL Not sure why you're worried about the fan speed. Let the thing blow and move that heat out away from your plants. TWW

 

Is your goal to always keep some level of air introduction...like to deal with humidity?

I'm about to step up my climate control setup so that I have a high/low temperature controller (two devices) and the same for a rH control.

I'll be able to...

Activate a heater at a designated low temp and a fan when it gets to a designated high temp.
Activate a humidifier at a designated low rH and a fan at a designated high rH.

Sure they'll kind of compete with each other at times but it'll probably only be in narrow ranges.

 

I'll bet that if you replace 1 or more lightbulbs in your house with cfls or leds you'll do better than managing fan speed.