Energiekennwerte

Energiekennwerte are standardized numerical indicators that express the energy performance of a building or system. They summarize energy demand into a single, comparable figure and are commonly used to assess and compare efficiency, prioritize renovations, and support regulatory or market instruments such as energy performance certificates.

Calculation and meaning: Energiekennwerte are typically derived from a building’s geometry, insulation, window quality, heating and cooling systems, hot water supply, ventilation, and climate data. They are usually given as annual energy use per unit of floor area and can refer to either end energy (Endenergiekennwert) or primary energy (Primärenergiekennwert). The resulting unit is commonly kilowatt-hours per square meter per year (kWh/(m²·a)) or an equivalent. The specific calculation method is defined by national or regional regulations and standards, such as Germany’s GEG, Austria’s ONR/ÖNORM guidelines, or Swiss SIA standards.

Applications: Energiekennwerte are a key component of energy performance certificates (Energieausweis) and are used in building permits, procurement, and labeling schemes. They enable benchmarking, help identify retrofit priorities, and support policy goals for reducing energy consumption and greenhouse gas emissions.

Limitations: These indicators are model-based estimates that assume standardized operating behavior and climate data. They do not reflect actual energy bills or occupant behavior, and comparisons should ensure consistent basis (Endenergie vs Primärenergie, same climate dataset and usage assumptions).

In practice, Energiekennwerte provide a concise, comparable measure of a building’s energy efficiency and are a central tool in planning, regulation, and market transparency in many German-speaking regions.