What is the specific heat demand for heating?

The specific heat demand for heating is the quantity that represents the thermal insulation properties of the building no matter how efficient the heating system and the heat source. It represents the amount of heat per unit area (kWh / m2 / year). This is an energy output from an object that is caused by the loss of the envelope.  

There are several types of calculations that set the limit for calculating the specific heat demand. It is controlled by standards ČSN EN ISO 13790, ČSN 73 0540-4, ČSN EN ISO 13789.  For low-energy houses, ČSN 73 0540 applies.