The first regulations for economising on heating energy came into force back in the nineteen seventies, as a response to the oil crisis. The first German Thermal Insulation Ordinance (WSchVO 1977) came into force in 1977. Just one year later the Heating Systems Ordinance (HeizAnlV 1978) came into effect and established a statutory basis for enhanced energy efficiency in systems engineering.
In the period that followed, a greater emphasis was gradually placed on climate protection due to climate change. Effective climate protection can, however, only be implemented on a trans-national scale. The European Union therefore introduced a directive in 2002 that was to increase energy efficiency in buildings.
In Germany, this directive was implemented into national law with the introduction of the Energy Saving Regulation (EnEV) in 2002. This new law on the reduction of the overall use of energy in buildings combined the thermal insulation ordinance with the heating systems ordinance. Whereas the thermal insulation of a building was formerly measured using the k-value, since the implementation of the Energy Saving Regulation (EnEV) the heating energy requirement is now calculated using the heat transfer coefficient U. Besides the heating and hot water demand this calculation also includes the heat losses through external elements and ventilation as well as the heat gain from the sun and electrical equipment in an energy balance that is used to determine the overall primary energy requirement of a building.
The standard of requirements for saving energy has been raised consistently and at shorter and shorter intervals over recent years. The EnEV 2009 reduced the limits that were set out in 2002 by approx. 30 % and for 2012 Uw-values of ≤ 0.95 W/m2K could be possible.
You will find further information and brochures on the Energy Saving Regulation online under www.enev-online.de