Hello MasonM, Have you thought about one of those Tube Heaters for a Greenhouse that you can get from ebay for about £12/16 ? It should be enough to keep your little Grow room warm when your lights are off or if you use CFL's.
And your Right about being Cold... I live in Wales on top of a Mountain and it's Trying to Snow as i Write this to you
Ive got to take my Dog for a walk in a bit... Not looking forward to that lol...
Take Care & Happy Growing.
Ps. if you need a link to the heaters that i mentioned give me a PM and i'll send you a link or 2.