The basic types of air conditioners are room air conditioners, split-system central air conditioners, and packaged central air conditioners. We will discuss them more in depth below.
Room Air Conditioners
Room air conditioners cool rooms rather than the entire home. If they provide cooling only where they're needed, room air conditioners are less expensive to operate than central units, even though their efficiency is generally lower than that of central air conditioners.
Room air conditioners generally range from 5,500 to 14,000 BTU per hour. The size needed depends on the size of the room, local climate and shading.
Central Air Conditioners
Central air conditioners circulate cool air through a system of supply and return ducts. Supply ducts and registers (i.e., openings in the walls, floors, or ceilings covered by grills) carry cooled air from the air conditioner to the home. This cooled air becomes warmer as it circulates through the home; then it flows back to the central air conditioner through return ducts and registers.
Split System
In a split-system central air conditioner the main components include:
- an outdoor metal cabinet that contains the condenser and compressor;
- an indoor cabinet that contains the evaporator;
- in many split-system air conditioners, the indoor cabinet also contains a furnace or the indoor part of a heat pump. The air conditioner's evaporator coil is installed in the cabinet or main supply duct of this furnace or heat pump.
If your home already has a furnace but no air conditioner, a split-system is the most economical central air conditioner to install.
Text description of the Split Air Conditioning System diagram.
A labeled diagram of a central air conditioning and heating system showing how air circulates through a building and connects to indoor and outdoor equipment.
- Cooled air: Arrows show cooled air traveling upward through a supply duct and entering the building through an upper vent.
- Warm air: Arrows show warm air entering a return vent and traveling downward through a duct labeled Warm Return Air.
- Filter: Located in the return air pathway near the furnace.
- Furnace: Connected to the return air duct and the indoor cooling unit.
- Cooling unit: Located next to the furnace and connected to the outdoor unit by refrigerant piping.
- Outdoor unit: Contains a compressor and a section labeled Heat From Indoor. Arrows indicate heat moving outward from the unit.
- Refrigerant piping: Connects the outdoor unit to the indoor cooling unit.
Packaged Units
The packaged central air conditioner is usually located outdoors and consists of one cabinet that contains the evaporator, condenser, and compressor. The cabinet is usually placed on a roof or on a concrete slab next to the house's foundation. The packaged air conditioner is connected to the indoor air supply and return ducts through the home's exterior wall or roof.
Since these air conditioners often include electric heating coils or a natural gas furnace, this combination of air conditioner and central heater eliminates the need for a separate furnace indoors. This type of air conditioner is used to cool and heat homes as well as small commercial buildings.
Text description of the ackaged Central Air Conditioner image.
A cutaway diagram of an outdoor air conditioning unit showing its internal components and their arrangement.
- Expansion valve: Located in the upper left compartment, connected to a series of pipes and cylindrical components.
- Cooling coils: A rectangular assembly of closely spaced coils positioned near the top of the unit.
- Condensers: Horizontal cylindrical components located in the middle section of the unit.
- Compressors: Two horizontal cylindrical components positioned in the lower section, with smaller cylindrical connections extending from their ends.
- Located Outdoors: A label beneath the unit indicates its outdoor location.