scope:

This standard gives a simplified calculation method for assessment of the heat use and energy needed for space heating of a residential building, or a part of it, which will be referred to as "the building". This method includes the calculation of: 1) the heat losses of the building when heated to constant temperature; 2) the annual heat needed to maintain the specified set-point temperatures in the building; 3) the annual energy required by the heating system of the building for space heating. The building may have several zones with different set-point temperatures. One zone may have intermittent heating. The calculation period may be either the heating season or a monthly period. Monthly calculation gives correct results on an annual basis, but the results for individual months close to the end and the beginning of the heating season may have large relative errors. Annex K provides more information on the accuracy of the method.