Rocket Mass Heaters: Superefficient Woodstoves ... -

An RMH typically features a J-shaped internal structure designed for maximum draft and heat extraction:

Rocket Mass Heaters: Superefficient Woodstoves Rocket mass heaters (RMHs) are a specialized space-heating technology that blends the high-temperature combustion of a rocket stove with the thermal storage capacity of a masonry heater. Unlike traditional woodstoves, which primarily heat air that quickly escapes, RMHs store heat in a heavy earthen "mass" that slowly radiates warmth for 12 to 24 hours after the fire has gone out. Core Components and Design Rocket Mass Heaters: Superefficient Woodstoves ...