Guides for purchasing a central air conditioner are found on a number of websites. Typically, these guides are available from home improvement organizations, such as Home Tips, consumer recommendation groups, such as Consumer Report and Consumer Search, and government bodies, such as the U.S. Department of Energy.
Generally, a number of electrical companies specifically furnish these guides in an effort to reduce electricity consumption. Spark Energy, for example, published a 2011 guide for purchasing an energy-efficient central air conditioner in the interest of saving consumers money on utility bills and reducing the electrical load of regional power generation companies. The electricity needed to run a central air conditioner in an average U.S. home creates approximately 3,500 pounds of carbon dioxide and 31 pounds of sulfur dioxide. This pollution is best mitigated with the purchase and use of a modern, energy-efficient central air conditioning unit.