Well shit! did you all know about thermostatic fans? rhino do them (as I’m sure others do)
They allow you to set the heat you want, and the fan controls the temperature of your room/tent! this seems revolutionary…
please google um’ if you haven’t heard about them, and if you have one then please give me your review on it, as they cost a good… 80 bucks more, but for heat control! it sounds worth it - all info or personal exp with these appreciated.
peace
Funny, just read and replied to a similar post…
I was looking at something like this as well. Only thing I didn’t like is the fan is either on (if too hot) or off (if not too hot). I always want my fan on at least a little to keep neg. pressure to contain smell. Let me know how it works.
If you get one please post how you like it.
Oh… oh… I see. I thought they stayed on, but sorted heat problems out also = what a pain! surely you can keep it on and it changes speeds for heat but never turns off 
il get back to you with any info I find on what we both (and everyone no doubt) wants
The one I looked at was a digital setup with multiple outlets and it couldn’t always have them on at some low speed. It should have set points that it always stays between but I haven’t seen that. Haven’t looked very hard either though
Titan controls will do the same with less costly devices .
They cost a tone from what I’ve seen, cheaper to buy one with a controller than one of those separately. I think the plug into wall controllers (cheap as chips) look ok, 20$ for a decent one, and they seem to do the job for single speed fans
The cheap speed controls work fine no need to get crazy I personally like to keep my box in a negative pressure so I never turn off my intake or exhaust just slow them down if needed 
Happy growing