A rack system would likely be the better option to maintain temp/humidity. The AP T8 is very good however, but if you're living in a draftier home then I would see about getting a Radiant Heat Panel for the warm side, and you can run a small piece of heat tape on the cooler side, just make sure it's dialed in around 82ish. This way by the time it penetrates through the PVC & substrate it'll be in the higher 70's. It's a little bit more expensive of an option, but that's why I said a rack would likely fit your price better.

Another option is to heat the room with something like a space heater.