The energy performance of a building shall be expressed by a numeric indicator of primary energy use in kWh/(m².y) for the purpose of both energy performance certification and compliance with minimum energy performance requirements. The methodology applied for the determination of the energy performance of a building shall be transparent and open to innovation.

Member States shall describe their national calculation methodology following the national annexes of the overarching standards, namely ISO 52000-1, 52003-1, 52010-1, 52016-1, and 52018-1, developed under mandate M/480 given to the European Committee for Standardisation (CEN). This provision shall not constitute a legal codification of those standards.

The calculation of primary energy shall be based on primary energy factors or weighting factors per energy carrier, which may be based on national, regional or local annual, and possibly also seasonal or monthly, weighted averages or on more specific information made available for individual district system.

Primary energy factors or weighting factors shall be defined by Member States. In the application of those factors to the calculation of energy performance, Member States shall ensure that the optimal energy performance of the building envelope is pursued.

In the calculation of the primary energy factors for the purpose of calculating the energy performance of buildings, Member States may take into account renewable energy sources supplied through the energy carrier and renewable energy sources that are generated and used on-site, provided that it applies on a non-discriminatory basis.

For the purpose of expressing the energy performance of a building, Member States may define additional numeric indicators of total, non-renewable and renewable primary energy use, and of greenhouse gas emission produced in kgCO₂eq/(m².y).

1. (a)

   the following actual thermal characteristics of the building including its internal partitions:

   1. (i)

      thermal capacity;

   2. (ii)

      insulation;

   3. (iii)

      passive heating;

   4. (iv)

      cooling elements; and

   5. (v)

      thermal bridges;

2. (b)

   heating installation and hot water supply, including their insulation characteristics;

3. (c)

   air-conditioning installations;

4. (d)

   natural and mechanical ventilation which may include air-tightness;

5. (e)

   built-in lighting installation (mainly in the non-residential sector);

6. (f)

   the design, positioning and orientation of the building, including outdoor climate;

7. (g)

   passive solar systems and solar protection;

8. (h)

   indoor climatic conditions, including the designed indoor climate;

9. (i)

   internal loads.

1. (a)

   local solar exposure conditions, active solar systems and other heating and electricity systems based on energy from renewable sources;

2. (b)

   electricity produced by cogeneration;

3. (c)

   district or block heating and cooling systems;

4. (d)

   natural lighting.

1. (a)

   single-family houses of different types;

2. (b)

   apartment blocks;

3. (c)

   offices;

4. (d)

   educational buildings;

5. (e)

   hospitals;

6. (f)

   hotels and restaurants;

7. (g)

   sports facilities;

8. (h)

   wholesale and retail trade services buildings;

9. (i)

   other types of energy-consuming buildings.