I agree with Spaniard -- you can get a cheap heat mat and rheostat for under $25. Stick it on the other side, and run it all the way at low if necessary.

Alternately, you could buy a room heater and bump the ambient air temp up a few degrees, and just turn your hotside UTH down (if that would even be necessary). Oil-filled heaters are under $40 at Walmart or Home Depot, and they are safe to run 24/7 as far as I know.