Fakten
Important physical parameters
Annual primary energy demand Q"p
The most important threshold value of the EnEV (Energy Conservation Regulation). It represents the result of a comprehensive calculation of the energy standards of building envelopes and engineering systems.
Transmission heat loss H´T
It represents the total heat loss of the building envelope. Since H´T is directly related to 1 m2 of heat transmitting envelope surface, it can also be referred to as the average U-value.
System expenditure factor ep
Describes the efficiency of the system equipment such as heating and hot water production. This includes all losses from production to delivery. The higher the efficiency of an energy system, the lower the system expenditure factor.
Annual heating demand Qh
Constructed heating demand, which is required to maintain a certain average room temperature. This value is also known as net-heating demand.
Year-end energy demand QE
Amount of energy that is needed for a building under standardized conditions for its heating and hot water supply. 10 kWh of final energy correspond to about 1 liter of fuel oil or 1 m3 of natural gas.
