Rheostats don't work with heat tape. However, if you end up using heat pads, I recommend them as a cheaper alternative to a t'stat. While they will still fluctuate, it helps keep control of the temps. But when it comes to heat tape, a top notch t'stat is the only way to go. I know there are all kinds of cheap t'stats, but honestly, if you want one to work (which you do, because without a working t'stat, the heat tape will burn your house to the ground, it gets that hot), you should be looking at $80+. As I mentioned before, Ranco and Johnson t'stats work wonderfully and are for a fair price (I got my Johnsons for $100 shipped).