Summary: Air gets into and out of our homes from a wide range of places. Many of these can be fixed with some simple do it yourself handiwork. Undertake any of these and you’ll start to realize instant energy savings. According to the U.S. Department of Energy, American homes lose energy from the following places (in decreasing order of importance): floors, ceilings and walls (31%), doors and windows (21%), heating/air condition ducts (15%), fireplaces (14%), plumbing penetrations (13%) and all others (6%). Recognize that these numbers may vary based on home type, age, geographical region and other factors.