It's a 110. Now, I'm completely confused, because the guy's video does NOT match up to his wiring diagram at all. Not to mention, his wiring diagram doesn't match up with the wiring diagram from the actual thermostat. The thermostat has the two bays connected, his diagram does not, and when you wire to his diagram, the thermostat won't even turn on. I found out WHY my stupid relay was fried (THANK GOD I bought a second one because I was being impatient!!!) The rat's nest that was in there from the original wiring and then Ed's additional rat's nest had everything all funky. I completely removed my indicator light on the bator, which was connected to the main power source, AND the relay, and that's where the power came from to fry the relay. Now, my indicator light will not work, because I honestly don't know how to wire that in, HOWEVER, the thermostat, provided that I get this all correct the second time around, has it's own indicator light. Now, I have to figure out exactly how to connect the two bays in the thermostat together, when one is supposed to be a DC, and it's supposed to also be connected to the relay, which is AC... Since I'm literally electrically retarded, this is extremely difficult for me. I look at a simple light bulb connection, which I know is easy, and I can connect the idea that it's easy enough and should be simple, I am just missing some kind of connection in my head that tells me HOW to do it. I can't even explain why it doesn't make sense to me, lol.