I heard of "old guys" doing this for rural cabins in Colorado. They would take old 4 cylinder VW pancake motors, convert 2 of the cylinders to compress air, ru

I heard of "old guys" doing this for rural cabins in Colorado. They would take old 4 cylinder VW pancake motors, convert 2 of the cylinders to compress air, run the remaining 2 on gas, and then use the waste heat to heat the cabin. Then you have compressed air, heat, and electricity (you use the motor to spin a generator)