Quote Originally Posted by TimNA View Post
I built one just like this, in the summer it's great but in the winter as you are worried it's hard to keep the ambient without a heated room. Since it is open it wont hold heat at all. I ended up having to get a oil filled heater to heat the room. Only way around not heating the room would be to make it with the front/back enclosed & only open on the small end, (if that makes any sense).

I also use 11" flexwatt & no it wont heat the cool side at all. I have it measured at 1ft long which covers about 1/3 the tub but, a few inches away from the flexwatt it's ambient temp.
I originally wanted to design an inner and outside layer of the rack. Use something like a very thin cardboard like base to surround the tubs with. Then layer that with insulation [foam], followed by the 3/4 inch shell around that.

Currently i use a heat lamp to keep the ambient temperatures up. When the winter first started and the temperatures dropped to about 68 (Normal winter temperatures) i went to fire up the heat lamp and it was broken. So Lilly went with out a heat lamp for about two weeks (which is about two feeds). I noted that the feeding response was normal and her hot side was still averaging 92-93 degrees.

Its noted that i do plan to seal all sides of this rack except the front.

One method i had in mind
Buying another ranco thermostat which would hook up to yet again another piece of 11" flex watt which i would use to try to bring the cold side temperatures up. [Assuming heat rises, i could essentially set the thermostats to 92-93 degrees for basking, and 80-85 for the cool side]