The Rocket Mass Heater Builderвђ™s Guide: Complet... Apr 2026

The system relies on a strong internal draft created by the temperature difference between the hot riser and the cooling exhaust in the mass. Key Building Sections

by Erica and Ernie Wisner is a technical manual for constructing ultra-efficient earthen masonry heating systems. These systems can heat a home using 70–90% less wood than a traditional woodstove by capturing exhaust heat in a thermal mass, such as a cob bench, which radiates warmth for 12–24 hours after the fire is out. Core Principles & Design The Rocket Mass Heater Builder’s Guide: Complet...

Covers site selection, floor load requirements (the mass is heavy), and navigating local building codes and insurance. The system relies on a strong internal draft

Includes firing practices to establish a draft and maintenance schedules for ash removal and inspection. Practical Benefits Core Principles & Design Covers site selection, floor

Forces extremely hot, clean combustion by keeping temperatures high enough to burn off soot and creosote.

The book provides detailed, step-by-step instructions across several phases:

Hot exhaust gases are routed through long horizontal channels (often inside a bench) that absorb and store heat instead of letting it escape up the chimney.