Mr. Heater F242300 10,000 15,000 BTU HeaterCooker
Heated up to 79 degrees in a little less than minutes. LOL then Bought the 3800 BYU Little Buddy which is sized for my shelter. Use the Mr Heater for cooking lunch in a cast iron skillet outside the shelter. Worked great in 13 degress. Set up with my ice slead as little wind block to prevent blowout which can happen in strong winds.