Oil filled heater with a built in thermostat that's set to "3." I think the scale goes up to 5... But then that's hooked to a hydrofarm on/off thermostat. Ceiling fan runs 24/7 for circulation. Keeps the room around 76-78. I also have the vent in the room open about halfway so the house heater/AC does affect the room a bit. I have to tweak the settings every season or so when we switch from AC to heat and back again. No night drop.
The door is also cracked open using this device: http://www.latchnvent.com. I have the cats' litter box in the snake room and this keeps the doggie with the hankering for kitty turds out. Also helps with circulation to keep the door cracked. Don't notice the heater working exceptionally hard (actually most times I go in there and its off).