When choosing a central air condition unit, it is important to consider size, cost and type of unit. The choice of size is particularly important, as an improperly sized unit can result in severe loss of energy efficiency and other problems.
Many contractors urge a purchaser to select an air condition based solely on the size in square feet of the home. The United States Government's "Home Energy Saver" guide, however, suggests a more thorough process. The contractor should measure each room, including ceiling height, as well as length and width. He or she should also consider the number of occupants, roof color, and insulation, as well as local climate.
There are two main types of central air conditioner: a split system with a condenser outdoors and a blower indoors, or a system with all of the main components outdoors. The first of the two is much more energy efficient, though some homes are not equipped with the proper duct work for such systems. In these cases, there are various solutions that allow central air to be installed, though sometimes at a loss of energy efficiency. A greater outlay of money at the point of purchase can often result in a much more efficient overall system, which is not only good for the environment but can result in large savings throughout the life of a system.