How are you keeping his warm side warm?
What are you measuring temps with?
Is it a tank, tub, or other type of enclosure?
Do you have a thermostat?
Is there any substrate or is it paper towels / newspaper?
Need just a bit more info to help. 75 is a bit low in my opinion - I keep my ambient around 80*F +/- a degree. Esp being in Utah, I imagine your house is cool in the winter so this isn't something you want to wait on.