To mitigate the environmental impact of the building industry, the European Commission is promoting energy efficiency. Increasing the annual renovation rate of the building stock is a priority. Buildings must achieve a new standard: the Net Zero building. To be Net Zero, a building must produce enough renewable energy to balance what it consumes over a year. The Passive house institute points out two drawbacks in this standard: First, the storage losses of renewable energy are not taken into account. Second, the Net Zero definition is adapted and different in every EU country. The institute developed the EnerPHit standard to tackle these drawbacks.

The Net Zero concept has various definitions, the Passive House institute defines a Net Zero Building as a building producing enough renewable energy within its footprint to balance its annual primary energy renewable (PER) consumption. We introduce the Net Zero Potential (NZP) of a building: its energy production divided by its PER consumption. To evaluate the NZP of EnerPHit renovated buildings comparing to the NZP of national renovations, twelve study cases with different typologies and locations are analyzed. The buildings are located in Germany, Spain, Greece, and France. These locations have different climates, regulations, and energy mix. In this study, we consider photovoltaic panels as our unique renewable source, taking the LCA of the panel into account.

As a result, the EnerPHit NZP varies between -13% and +124% compared to the national requirement NZP. The results vary depending on the typology and location of the building. EnerPHit renovation have, on average, a higher NZP than national renovations. The gap between the NZP of EnerPHit buildings compared to the NZP of buildings renovated according to national regulations is higher in Germany than in the other countries, and for five-story buildings than for other buildings. The gap is smaller in Greece compared to other countries and for three-story buildings compared to other building types.