Unitary air conditioners are factory-made assemblies that normally include an evaporator or cooling coil and a compressor/condenser combination, and possibly provide heating as well. An air-source unitary heat pump normally includes an indoor conditioning coil, compressor(s), and an outdoor coil. It must provide heating and possibly cooling as well. A water-source heat pump rejects or extracts heat to and from a water loop instead of from ambient air. A unitary air conditioner or heat pump with more than one factory-made assembly (e.g., indoor and outdoor units) is commonly called a split system. General Design Considerations Types of Unitary Equipment Equipment and System Standards Air Conditioners Air-Source Heat Pumps Water-Source Heat Pumps Variable-Refrigerant-Flow Heat Pumps