In 1993, heating and cooling accounted for 58% of energy consumption in American homes. By 2009, according to statistics gathered in the Residential Energy Consumption survey conducted by the Energy Information Administration, that number decreased all the way down to 48%. Several factors contribute to this trend, including more efficient heating and AC systems, better insulation, and windows that help temperature control. However, that trend also depends on heat and cooling service experts who are able to make sure that systems run efficiently on a consistent basis. Without the right maintenance and upkeep, heating and air conditioning units could encounter a number of problems that cause them to burn more energy than they need.