Mine tends to run continually because we don't keep our entire house at 77 degrees like I want my snakeroom to be at. Because I have a digital heater - I had to set my ranco at 85 degrees with my heater at 75 degrees - which means the ranco is only a safety shut off in the event that the digital built thermostat on the heater fails - so technically my heater is on most if not all the time.