Calculation of the energy index

The energy index serves as a measure of the energy consumption, which results from the interaction of the properties of the building shell, the selected eating system, other building services installations, the local climate, the mode of operation and the user behaviour. In order to be able to calculate the energy index, the reference value for energy reference area must be determined. The energy reference area is the sum of all areas, for which the use of heating is necessary. This usually includes all common rooms (living, dining, kitchen, sleeping, wet rooms and hobby rooms), but also stairwells and corridors. Unheated rooms such as laundry rooms, heating and technical rooms, garages and cellars are not included in the energy reference area.

Calculation of the energy index

• Heating including hot water = total heat
  
• All heated surfaces = energy reference area
• Total heat (kWh) / energy reference area (m²) = energy index Ew (kWh/m²)
  
  

If the energy requirement for hot water is included in the heating output, this must be deducted from the calculation.

Assessment