The purpose of the standard is to:
a) collate results from other standards that calculate energy use for specific services within a building; b) account for energy generated in the building, some of which may be exported for use elsewhere; c) present a summary of the overall energy use of the building in tabular form;
d) provide energy ratings based on primary energy, carbon dioxide emission or other parameters defined by national energy policy;
e) establish general principles for the calculation of primary energy factors and carbon emission coefficients. This standard defines the energy services to be taken into account for setting energy performance ratings for planned and existing buildings, and provides for this:
f) method to compute the standard calculated energy rating, a standard energy use that does not depend on occupant behaviour, actual weather and other actual (environment or indoor) conditions; g) method to assess the measured energy rating, based on the delivered and exported energy;
h) methodology to improve confidence in the building calculation model by comparison with actual energy use;
i) method to assess the energy effectiveness of possible improvements. This European standard is applicable to a part of a building (e.g. flat), a whole building, or several buildings. It is up to national bodies to define under which conditions, for which purposes and for which types of buildings the various ratings apply. This standard handles the energy performance of a building as a whole. The assessment of the energy performance of specific technical building systems is handled in the appropriate part of EN 15241, EN 15243 and EN 15316 series.