(NAPSI)âSpring isnât just when we spring forward in time, it is also the time when we spring into action to clean those places that likely havenât been cleaned at all: your heating and cooling air ducts. That can be a problem because thatâs where dirt, germs, mold, mildew, pet dander and other allergens like to lurk. A six-room house can generate as much as 40 pounds of dirt, chemicals and pollutants in a typical yearâwhich this wasnât for many families. The contaminants make the heating and cooling system work harder, use more energy and wear out faster. That can get expensive. According to the U.S. Department of Energy, 25 to 40 percent of the energy used for heating or cooling a home is wasted.