Masonry heaters consist of a firebox, a masonry mass, and heat-exchange channels in the masonry mass through which gases from the fire pass and then are released to radiate heat. The firebox, where the wood burns at temperatures as high as 2000°, is constructed of low-expansion clay firebrick. A network of heat-exchange channels within the masonry directs the fire’s hot gases through the unit, which absorbs and releases heat for as long as 24 hours. So instead of venting wastefully out the chimney as with a fireplace or wood stove, the warmth created by the fuel radiates throughout the home for hours.
Zander’s designs evolved using centuries-old concepts that originated in the sub-Arctic climates of Northern Europe, employing materials and plans he has refined over years of research, engineering, knowledge and plain old Yankee ingenuity to comply with building codes and environmental standards.