Connected heat pumps and air conditioners - test and determination of performance characteristics

Last updated: 25 July 2020

ISO 13253:2017 specifies performance testing, the standard conditions and the test methods for determining the capacity and efficiency ratings of air-cooled, air-conditioners and air-to-air heat pumps.


ISO 13253:2017 is applicable to ducted air-cooled air conditioners and ducted air to air heat pumps.


ISO 13253:2017 is limited to

  •  residential, commercial and industrial single-package, and split-system air conditioners and heat pumps,
  •  factory-made, electrically driven and use mechanical compression,
  •  utilizing single, multiple and variable capacity components, and
  •  multiple split-system utilizing one or more refrigeration systems, one outdoor unit and one or more indoor units, controlled by a single thermostat/controller.


The requirements of testing and rating contained in this document are based on the use of matched assemblies.


ISO 13253:2017 is not applicable to the rating and testing of the following:

 a) water-source heat pumps or water-cooled air-conditioners;

 b) multi-split-system air-conditioners and air-to-air heat pumps (see ISO 15042 for testing of such equipment);

 c) mobile (windowless) units having a condenser exhaust duct;

 d) individual assemblies not constituting a complete refrigeration system;

 e) equipment using the absorption refrigeration cycle;

 f) non-ducted equipment (see ISO 5151 for testing of such equipment);

 g) ducted air conditioners and/or ducted heat pumps, rated at less than 8 kW and intended to operate at external static pressures of less than 25 Pa, controlled by a single thermostat/controller (refer to ISO 5151).


ISO 13253:2017 does not cover the determination of seasonal efficiencies, which can be required in some countries because they provide a better indication of efficiency under actual operating conditions.

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