SRE
The energy reference area (SRE, or Energiebezugsfläche in German) is the sum of a building's heated or air-conditioned floor areas under standard SIA 380/1. It is the denominator of energy performance indicators and the basis on which cantonal subsidies paid per square metre are calculated.
The energy reference area counts the internal areas of rooms whose heating or cooling is part of their intended use, including internal walls and partitions. An unheated garage, a cold attic or a cellar outside the thermal envelope are excluded. The reference is standard SIA 380/1, adopted by the cantonal energy regulations harmonised through the MoPEC model.
It should not be confused with gross floor area, which measures construction capacity and is used to calculate building rights. The two look similar but answer different questions: gross floor area tells you what you may build, the energy reference area tells you what you have to heat. On the same building, they almost always differ.
This is the figure that drives the money. Most cantonal renovation programmes pay an amount per square metre of energy reference area: façade insulation, window replacement, heating replacement. A misestimated area moves the entitlement directly, up or down.
It also drives regulatory requirements: heating demand indicators, MoPEC thresholds, energy certificate classes. Two buildings of equal volume but with differently heated envelopes are not subject to the same obligations.
Add up the floor areas of every room inside the thermal envelope, measured inside the external walls, and exclude unheated volumes. The Federal Register of Buildings and Dwellings (RegBL) publishes an energy reference area per building: the most reliable starting point, to be confirmed by a survey if the building has been altered since it was declared.
Gross floor area measures construction capacity and feeds the building-rights calculation; the energy reference area measures heated area and feeds energy calculations and subsidies. An unheated basement may count in one and not the other.
Because most cantonal rates are expressed in francs per square metre of energy reference area. The amount is therefore directly proportional to it, usually with a cap per measure.
The RegBL publishes a value per building, identified by its EGID. It works as a starting point; a subsidy application still requires an energy certificate or a professional survey.
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