Test procedures are the basis for quality labels, calculation models and therewith an important element in governmental policy instruments. However world-wide there is a disturbing landscape with a great number of test methods for heat pump water heaters in use in different regions of the world, with major differences between them. As a result, manufacturers have to undertake a different set of tests to be able to sell their products on the worldwide market. Harmonisation of test procedures is urgently needed.

The ISO Working Group 12 on Heat pump water heaters of ISO/TC 86/SC 6/WG 12 on HPWHs has developed a harmonisation framework, for drafting  a test procedure now available as standard  ISO 19967-1:2019.

The European standard EN 16147 and the ISO 19967-1 standards are very similar and are assessing the water heating energy efficiency of the heat pump water heaters based on the rating of a coefficient of performance (COPDHW) over a 24h load profile (Annex presentation). Several load profiles, each one consisting of a series of draw-offs characterised by the hot water outlet temperature and the amount of energy tapped, are described and  allow to rate a large capacity range of heat pump water heaters. In addition, if the unit is provided with a smart control, i.e. self-learning of the hot water usage, the coefficient of performance can take benefit of this smart function. Other characteristics such as the standby power input and the volume of available water at 40°C within one single draw-off are also performance parameters of the heat pump water heater.

Quality Labels

Standards are used for various purposes at legislative level and for other purposes:

  • Energy performance labelling, like European ECO label, TOP Runner in Japan, China Energy Label (CEL), Energy Star and Energy Guide labels in North America
  • In practice, standards are also used for design purposes used in a number of (often commercial) calculation models.
  • Governmental information models, like the SAP (add abbreviation as footnote) and RdSAP models in the UK with which the EPC for the building is calculated
  • Also Heat Pump Associations develop models

Traditionally, energy efficiency standards and labels have set performance requirements for water heaters by type (e.g., storage electric water heater, gas instantaneous water heater, etc.), thus inhibiting the comparison across water heater technology classes.

Work to be done

Many of the test procedures focus mainly on air source Heat Pump Water Heaters (often mon-bloc), being the main stream, while there is a large number of alternative and often innovative new heat pump technologies supplying domestic/sanitary hot water. For these there are no standardized test procedures available or if available not acknowledged at international level.

Annex Report on Test Procedures

The Annex has in its collaboration analysed the work done on Test Procedures for Heat Pump Water Heaters. The Final Report on this is available and can be downloaded.