. . . Not long ago, in an effort to learn why some heaters work better than others — and with the eventual goal of building an effective, affordable high efficiency fireplace — New Mexicans Bob Christensen and Alex Sanchez began to research various stove designs. The pair initially concentrated on modifying the basic shape and configuration of the "standard" firebox . . . but when they discovered that plate steel couldn't be easily conformed to the pattern they wanted, the inventive Southwesterners decided to try a different tack. . .

Build a High Efficiency Fireplace (90% Efficient!) - Do It Yourself - MOTHER EARTH NEWS