describe your setup.. is it a glass tank?

Temperature in your enclosure will be a function of insulation, ventilation, and energy(heat) output of your heating elements.

If I was trying to heat a glass screen top enclosure, I would use an under tank heater and a heat lamp with a 60+ watt bulb/CHE, and I would insulate 3 of the sides and cover most of the screen top with aluminum foil.

Humidity becomes a huge issue if you need to heat a tank greatly above room temps. Humid hides, wide water dishes, and heaps of moistened moss will help.

The issue of cold rooms is a good argument for rack setups for ball pythons. I use sterilite tubs for my snakes that are prone to humidity problems in the dry climate I live in.