Snake viv how to heat questions?

I would get a larger heat pad and I wouldn't put any heat source that a snake can lie on that doesn't have a thermostat. You should have the probe from the thermostat at the level of the heat pad under the warm side hide. Get a decent digital thermometer and put the probe on the cool side to see what your temps are there at substrate level. Your house should not be that cold. Even if it's 13 outside, I'd suspect you don't keep the interior of your house that cold. If it's tolerable to you, it is to the snake. It's possible that the snake is going to shed. Mine routinely spend more time on the warm side at that time. Otherwise they utilize the cool side.