This is an international R&D project on the evaluation and demonstration of actual energy efficiency of heat pump systems in buildings. The project is within the framework of the EBC TCP on Energy in Buildings and Communities (EBC).

Certain heat pump systems in buildings have previously been found to exhibit low energy efficiency under low partial load conditions, while other heat pump systems have been able to maintain higher energy efficiency under the similar conditions. Therefore, technical guidance on how to improve the overall energy efficiency of such heat pump systems is critical information for many engineers and HVAC system designers. Further, public policy and decision makers require support on how requirements to follow such technical guidance can be implemented within building energy codes and regulations.