A new evaluation procedure, focusing on “Primary Energy Renewable” (PER), serves as a basis for these new classes.
The heating demand of a Passive House may not exceed 15 kWh/(m²a). This will continue to apply, but with the introduction of the new categories, the overall demand for renewable primary energy (PER) will be used instead of the primary energy demand, which was previously used. In the case of the Passive House Classic category, this value will be 60 kWh/(m²a) at the most. A building built to Passive House Plus is more efficient as it may not consume more than 45 kWh/(m²a) of renewable primary energy. It must also generate at least 60 kWh/(m²a) of energy in relation to the area covered by the building. In the case of Passive House Premium, the energy demand is limited to just 30 kWh/(m²a), with at least 120 kWh/(m²a) of energy being generated by the building.
The sun and wind provide primary electricity. Some of this electricity can be used directly. However, storage capacities are necessary for transferring surplus energy to time periods with lower energy gains. These supply secondary electricity as required, and this is associated with losses. Depending on the type of energy application, the proportion of primary and secondary electricity varies, as do the losses for providing energy. These specific energy losses of an energy application are described as the respective PER factor. The demand for domestic energy is quite constant throughout the year, which is why the share of direct electricity is high and the PER factor is low. In contrast with this, heating is necessary only in winter. In order to provide enough energy in winter, electricity must in part be produced in summer and stored with very high losses for the winter, which results in a high PER factor.