I've got pvc cages with both radiant heat panels and flexwatt. My house stays about 68 in the winter and with both running it usually ends up with the cool end 75-77, this isn't running them full blast but in hindsight I might have gotten larger rhp or maybe placed it differently or had the flexwatt on the cool end. I'd prefer my low end to stay 78-80 like it does in the summer without overworking the heating elements. I've decided to heat the room instead this winter with a radiator and hope that will be easier.