This test procedure was developed to provide a uniform method of testing for rating the seasonal efficiency of multipurpose heat pumps, referred to herein as combined appliances, which perform space conditioning and water heating in residential applications. The heat pumps may also provide additional functions, such as ventilation and/or dehumidification. This procedure pulls together past test procedures and U.S. Department of Energy waivers dealing with special design equipment into a single comprehensive procedure covering all existing and anticipated multipurpose heat pumps.

This procedure is voluminous but covers six different basic systems: single capacity air-source, dual capacity air-source, variable capacity air-source, single capacity liquid-source, dual capacity liquid-source, and variable capacity liquid-source systems. Some material is repeated for each system type in order to minimize the need for the reader to refer to other sections of the procedure.

The 2024 edition of Standard 206 updates references.