UTH do not contribute to ambient temps they are strictly for belly heat. I put my accurite digital hygrometer/thermometer in the front middle of my cage. That make it a little warmer on the hot side and a little cooler on the cool side. My heat gun measures the temp at the heat mat, on top of the hot hide and inside the hot hide on the substrate. My hygrometer/thermometer stays at 60% and between 80-81. I don't use a space heater. I have baseboard heating which never goes above 72 if ever. If you set up your tanks correctly you won't have an issue.