An article titled the “Fireless Furnace” appeared in the Oct. 25, 1948, issue of LIFE magazine. There, postwar America witnessed the emergence of a futuristic technology that Lord Kelvin, the king of cold, only dreamed about a century earlier. The fireless furnace avoided burning fossil fuels by piping water through coils in the ground and then through a heat pump. But the technology was too expensive—about $3,000 installed—and too new to gain acceptance. “However, as the efficiency of getting heat from the earth improves, it is almost certain that eventually the heat pump will be able to compete successfully with conventional heaters in most localities,” said the story.
Sixty years later, geothermal-heat pumps (GHPs) and related systems are competing. If designed to be efficient, these systems can produce more energy than they consume—three to five times as much on average—yielding a positive coefficient of performance (COP). But a system’s ability to save the owner money still remains a huge question, considering manufacturers’ equipment labels do not always match real-life performance due to loose regulations; engineers are still struggling with design complexities; contractors are demanding a wide range of drilling, trenching and fit-up fees; the varying geology and climate across the U.S.; and fluctuating energy prices.