SR237 The energy performance of heat pump water heaters (2018)

The energy performance of 11 heat pump water heating (HPWH) systems was examined by installing data-logging equipment to the systems. These 11 systems included both integral HPWH systems as well as split system HPWH systems. Three of these systems were from an earlier project examining solar water heating (SWH). The remaining eight systems were part of an audit subspace of a much larger (more than 160 systems) but less detailed study of HPWH system performance being undertaken by EECA.

The results of the data monitoring showed the performance of the integral HPWH systems was reasonably consistent, although the split systems had varied performance. The three once through split systems performed better than the integral system, and the one recirculating split system performed poorly.

Analysis of the energy consumption was made with comparison to the amount of water drawn off from each system as well as the ambient temperature the units were exposed to. The energy performance of an HPWH system is reduced as the quantity of the water drawn off from the system is reduced or if the HPWH system is operated in a cooler environment.