I have a juvenile sulcata and we’re building his winter housing. It’s a small greenhouse, off the floor, with a custom built heating system below. In the pictures you will see two cut out holes in the floor where the heater underneath pumps the air (one for intake and outtake). It went down to 32 F last night outside and the overall temp of the cage inside, registering in the middle and up in the air (not ground level) was 52F at the lowest point. I’m assuming a few degrees warmer on the ground. Highest peak for the day was only 72F inside. My husband thinks one infrared bulb will be plenty to bring one area of the cage up to temp. I believe we need a true visible basking light. Our argument is visible light vs non visible light. I don’t think he can get true basking temp from a non visible light.