A rocket mass heater is an earthen masonry heating system which provides clean, safe and efficient warmth for your home, all while using 70-90% less fuel than a traditional woodstove. These unique and beautiful installations provide luxurious comfort year-round. In cold weather a few hours of clean, hot burning can provide 20 or more hours of steady warmth, while the unit's large thermal mass acts as a heat sink, cooling your home on sizzling summer days. Packed with hard-to-find information, includes: Earthen masonry heating systems are well-suited for natural and conventional builders alike. A super-efficient, wood-burning, rocket mass heater can help you dramatically reduce your energy costs while enhancing the beauty, value and comfort of your home.