tub not a option, tank size?

[RichsBallPythons]

Ambient temps. Oil is expensive.Keep our house at 68-70 tops.

Then tub will be your option not a glass tank that loses heat faster than plastic does.

Cold rooms tanks dont do well unless a lot of effort and time go into it. Plastic tubs will help hold in the heat and humidity with simple UTH covering 50% of the bottom.