Outside air conditioners provide cooling throughout the home, use existing furnace duct work, do not take up window or floor space, and are more efficient and quieter than in-home air conditioning units. Also known as central air conditioners, these systems provide cleaner air and the convenience of thermostat-controlled, consistent cooling.
Some outside air conditioners are split systems. An outdoor cabinet holds the compressor and condenser coil while an indoor coil sits on top of the furnace. Some packaged air conditioning systems require just the outdoor cabinet.
Swamp coolers are another outside air conditioning system suitable for use in areas of low humidity. Swamp coolers evaporate water into the air by passing warm air over water-soaked pads. All outside central air conditioning systems require regular maintenance. Duct leakage can result in up to a 30 percent decrease in energy efficiency if not assessed and corrected. In 2015, average installation costs for central air conditioning systems can run between $1,500 and $9,500.
Indoor air conditioners are less expensive than installing a central air system, but usually cool only one room and can be noisy. Portable air conditioning units drain water inside the home, and window units drain it outside; these problems aren't associated with outside systems.