With two small heating pads, and all the other stuff we've done, they stay pretty warm. Before the heating pads, they were really cold and barely moved. Now they are happier and moving around a lot more. Kind of like in the warm summer we all love (and already miss lol). During the day it's wonderfully warm due to the sun, but at night it is freezing. There may be a draft at the base of the run letting the colder air in. We put it as close to the ground as we could, but it can leak right in down there. I'm not really worried about a fire starting. We keep the straw very thick, and the mats/wires are protected enough. The surge protector is higher up on the wall, and the unused outlets close to avoid anything getting in by accident. A lot safer than getting a heater like we were originally planning. They absolutely LOVE the heating pads.