Worried about energy consumption? Install a programmable thermostat inline with your exhaust system! I made this tutorial to show just how easy and cheap it is to add automation to buckets and totes. If you don't like programming your own system with a Raspberry Pi or an Arduino, here is a cheap and easy solution that you can use as a template. I used a 12v Relay LED digital thermostat switch sensor. I don't recommend using this for more than 24v. The power supply is 12v and 6A: overkill for one PC fan and a thermostat, but that leaves me room for upgrades. I added a diagram of the 4 wire cord and 4 port terminal connections. Switching is done after the load (which is not normal) but control wiring is a different game.