The trend of continually rising market shares of compression heat pumps operated by electricity used for heat supply in buildings will continue in the future. Although people still opt for this technology mainly due to economical reasons, the ecological aspect becomes increasingly important in the decision-making process. The energy provided by heat pumps is defined as regenerative by the recently introduced Renewable Energy Heat Act (EEWärmeG). The EEWärmeG seeks to increase the share of renewable energy used for the heat supply. For the evaluation of both, economical and ecological factors, the proven efficiency of the heat pump systems is of central importance as well as the future potential of this technology.

In the framework of the project "WP Monitor" an independent and high-quality measurement of almost 100 heat pumps will be conducted. In order to determine the seasonal performance factor (SPF), essential factors will be taken into consideration. Measuring additional data and gaining minute values allows for much detailed analysis. Thus one can focus more extensively on process temperatures or issues such as operation times. The serially manufactured heat pumps are provided by twelve German and Austrian manufacturers. Each pump is analyzed for at least 30 months which guarantees the consideration of at least two heating, i.e. winter and summer periods.

The project's primary objective is to independently evaluate current heat pump systems of individual manufacturers and to determine characteristical values. In this context systems which had not been considered in the project "WP-Effizienz" (e.g. direct evaporation systems or plants with speed-controlled compressors) should also now be taken into consideration. As already done in previous monitoring projects of the Fraunhofer ISE, further optimization possibilities should be identified and errors (installation) by heat pump systems should be uncovered. The acceptance of heat pump technology can be promoted further by presenting the results and making them available to the public. Smart Metering is another interesting topic, particularly for the energy suppliers who are among our project partners. The possibilities to connect Smart Metering and heat pumps will be examined in detail as well.