Central air conditioners work by moving air through a duct system, using supply ducts and registers to send cooled air to the home and return ducts and registers to send the warmer air back to the air conditioner again. There are two types of central air conditioners-split system units or packaged units. Split system units have an outdoor unit with a condenser and compressor and an indoor unit with the evaporator. The indoor unit will often be combined with either a furnace or the indoor unit of a heat pump. With a packaged unit, all components are combined in an outdoor unit that may be located on the roof or next to the house.
The most efficient air conditioners today use 30-50% less energy as air conditioners from the mid 1970's. Even replacing a 10 year old air conditioner has the potential to save you 20-40% of cooling costs. See the Energy Savers for more detailed information.
Estimate your potential to save energy and money by installing this product, please see the U.S. Department of Energy's Home Energy Saver calculator.