That's what I was curious about since I see so many setups with one strip of 3" and 4". The whole house thermostat is set to 69, but the room the cage is in is warmer. Our heat has been on the fritz lately, so that also might be causing that difference in temperature or at the very least adding to it. The enclosure I tried to mimic was this one with nearly identical materials (same wood, just different color). There is a gap of 1/8" from the top of the tub to the top of the rack, would that be doing it? The guy at Lowes cut the side pieces a bit higher than I had marked.

If I were to get a thermostat to regulate temperatures (I worry about the temperatures fluctuating with the rheostat since I have to manually adjust it), would there be an affordable (I see the Reptitemp 500r recommended a few times) one that I could plug two UTHs into? I was thinking of doing two flexwatt strips underneath, one regular and one with the rheostat to keep it lower for the cool side. Is this a feasible idea?