In 2013 our friend Merlin Jacov bought the "Love Bus" to live in but soon found himself spending more on propane to heat the darn thing in Cleveland winters than he would have spent on the rent he couldn't afford--about $30 per night. He heard how our home made rocket heater had dropped the heating bill for our double-wide from $1000 some months for propane to less than $100 per year for hardwood scraps from the flooring mill down the street. So he brought the bus to us and we fitted her out with a rocket heater made mostly from scrap metal and a DragonHeater cast refractory core. If I were to do it over I would use a 6" core (35,000 btu per hour) instread of a 4" core (20,000 btu per hour and fit at least a couple hundred pounds of cob mass in the upper barrel for longer lasting heat like we do in our newer CottageRockets. Jacov found he could gather enough scrap wood or twigs to heat the bus for the evening in a park or by the side of the road in a matter of minutes. Not having a mass battery like most Rocket Heaters means the bus is quick to heat up but it is also quick to cool down, so he still sleeps in a sleeping bag but his gas mileage didn't suffer any more than it already does from hauling around a big chunk of cob.