Just a cold weather data point, we've been comfortable in our gas Class A as low as -4 deg. F for a few days. We have two LP furnaces that do a great job of keeping the interior comfortable, and a small electric heater in the wet bay that kept everything from freezing except one small pipe to the accumulator tank. The only effect from that was the pump cycling more as if the tank wasn't there. Five minutes with a hair dryer fixed it. I will say we went through a lot of LP though, and were happy to move on to warmer weather.