Types of Residential Air Conditioning Systems

Central Air Conditioning System

• Central air conditioning is a fixture in 63.6 percent of American homes, according to the 2007 American Housing Survey. This is likely because most modern residences have ducts that central air units use to transfer air. There are two types of central systems: split and package. A split system consists of an outdoor unit that contains a condenser and compressor, and an indoor unit that contains an evaporator. A package system houses all components in one unit that's placed outside the home. If your home doesn't have ducts, central air is most likely not an option. According to the U.S. Department of Energy, adding ducts is most likely impossible if you're in a finished multilevel or single-story residence. In most cases, ducts are only possible if you gut the home as part of a remodel. An alternative is to try mini-ducts; however, not all installers offer mini-ducts.

Portable Air Conditioning System

• As the name suggests, a portable air conditioning system is an air conditioner that doesn't require installation. It's possible to place the unit in any room -- as long as a window is available for the unit's exhaust hose. The unit includes a window bracket for the exhaust hose. To relocate the unit, unattach its hose and bracket, and reattach in the room of your choice. "Consumer Reports" suggests using a portable air conditioning system as a last resort when no other choice is available. Tests run by "Consumer Reports" show that portable units underperformed when compared with window and central air systems. However, if you must choose a portable unit, pick one that has two hoses and automatically evaporates the condensed water.

Room Air Conditioning System

• When you have a room air conditioning system, it means you have a window air conditioner. The unit isn't portable, and requires installation into a window. The U.S. Department of Energy reports that a window unit costs less to operate than a central unit, but it isn't as efficient. It's possible that you'll have to install a new electrical outlet. If the window unit requires less than 7.5 amps of power, then any 15- or 20-amp plug will do. On the other hand, a window unit that requires more than 7.5 amps might need anywhere from a dedicated 115-volt circuit to a dedicated 230-volt circuit.

Evaporative Cooling System

• An evaporative cooling system is a special system designed to work in hot climates with low humidity. Evaporative coolers, also known as swamp coolers, use evaporating water and a steady airflow to cool the residence. According to Home Depot, an evaporative cooling system can lower indoor temperatures by up to 30 degrees. Home Depot also states that an evaporative cooling system uses 75 percent less energy than traditional air conditioning systems. However, an evaporative cooler use between 3.5 and 10 gallons of water per hour. It's your responsibility to make sure the unit's reservoir stays full. A portable evaporative cooler is available, but you also can choose a whole-house evaporative cooler. A whole-house unit installs on the roof or through windows and walls.