Energy Saving Regulation EnEV

The Energy Saving Regulation EnEV sets out thermal insulation standards that have to be observed in new buildings and in refurbishment projects. It is first and foremost aimed to save heating costs and to reduce environmentally harmful greenhouse gases such as CO2. The current energy saving regulation came into force in 2009 and is generally referred to as the EnEV 2009.

Key data:

  • The EnEV 2009 defines demands on energy efficiency in new buildings and renovated buildings
  • Energy efficiency is measured using the annual primary energy requirement of a building as well as the thermal insulation of the building envelope
  • It is expected that the ENEV 2012 will raise current requirements by a further 20 % (expected Uw–value ≤ 0.95 W/m2K)
  • Inoutic window systems already satisfy the expected values for 2012

Product overview Windows and Balcony Doors


EnEV 2009: The most significant values for windows and doors

Old buildings:

Windows Uw      1,3 W/m2K      (previously 1.7)
Front doors             
     2,9 W/m2K      (unchanged)

New buildings reference value:

Windows Uw      1,3 W/m2K
Front doors             
     1,8 W/m2K

(Uw=window, Ud=door )


The U-values (heat transfer coefficient) are the most important reference values for the Energy Saving Regulations. The heat transfer coefficient >U< indicates the amount of energy that flows through a surface area of 1m2 in one hour, when the two temperatures, on the inside and outside of the window, differ by 1 Kelvin (= 1 °C). The lower the U-value the better the thermal insulation.

Important: The given values relate to the required overall value of the window Uw. The Uw-value is a function of the U-value of the window frame Uf, the U-value of the glazing Ug as well as the linear heat transfer coefficient of the edge seal.

You will find more detailed information on U-values and the calculation thereof on our Info Page U-values.


Reasons behind the Energy Saving Regulation – the goal is climate protection

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 on or at one of our Inoutic partners near to you.

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