That work's or you can do something a bit easier. Get a room heater, and make sure its very secure where you put it. If you get cold at night get one of those window units that have heat and such. The easiest thing you can do however is goto lowes or home depot, and get a dimmer switch, put it where you need to for the day, mark it, and then put it where you need to for night and mark it. Then just move it from day to night as needed. It's cheap, it works great.
My parents wouldn't let me use a room heater, so I had to try anything haha to get the temps up.