Ralph Waldo Emerson never said “Build a better mousetrap, and the world will beat a path to your door.” The mousetrap that likely inspired the misquote was invented seven years after his death. Unfortunately, many people take it literally. GHPs have all the hallmarks of a better mousetrap: They do the job of heating and cooling a building more efficiently than any other option. Despite the larger up-front cost, they are a mature technology and usually the most economic option for buildings that can accommodate them.
Not only can GHPs cut energy costs for heating and cooling by up to 80%, they can also provide other benefits such as essentially free hot water when in cooling mode, lower reliance on fossil fuels, and the elimination of above ground outdoor equipment. These advantages have earned GHPs a small but dedicated cult of true believers, but not broad market acceptance.