Civil Engineering Reference
In-Depth Information
§ 5 Common requirements for statutory ordinances
(1) The requirements established in ordinances (…) shall be achievable
according to the available technology and cost-effective for buildings of the
same type and use. The requirements are cost-effective if the necessary
expenditures can in general be paid back with the occurring energy savings
during the useful lifetime of the measure. For existing buildings, the useful
lifetime, which can still be expected, has to be taken into consideration.
3.2.2 Energy Saving Ordinance (EnEV)
The EnEV was first introduced in 2002 and was then revised twice in 2007 and
2009. The next amendment of the ordinance is expected in 2013 (2014) although it
was initially planned for 2012. The regulation serves as a guideline and establishes
minimum requirements, calculation methods and recommendations for new resi-
dential and non-residential buildings, as well as for buildings undergoing moder-
nisations, reconstructions and extensions. For example, the ordinance prescribes
maximum primary energy demands, U-values of building elements, air tightness,
transmission losses, etc. The primary energy requirements and average specific
transmission heat loss (residential buildings), respectively average heat transfer
coefficients (commercial buildings), are defined by means of a reference building
which corresponds to the real building in terms of geometry, net floor area, ori-
entation and utilisation, but whose technical structure is defined according to
Appendix 1, respectively Appendix 2 of the EnEV ('reference building approach').
Furthermore, the EnEV establishes the start-up and maintenance of heating, hot
water, cooling and ventilation equipment and determines technical DIN norms
which have to be applied.
Chapter 5
of the ordinance engages with the issuing and
implementation of energy performance certificates and gives recommendations on
energy
efficiency
optimisation
techniques
(Regierung
der
Bundesrepublik
Deutschland
2009
).
As for residential buildings, the requirements for new commercial buildings are
also defined by the annual primary energy demand and U-values of components.
However, in addition to the energy demands for heating, hot water and air-con-
ditioning, the balance sheet also includes the proportion of energy for cooling and
lighting installations. The new comprehensive calculation method is defined in the
new German standard DIN V 18599 (dena
2013
). Figure
6
shows the chrono-
logical development of EnEV requirements.
According to the EnEV, a refurbishment, triggering technical requirements, is
defined as 'a change of an outer building component that exceeds 10 % of the total
building area of the respective component'. Example: If you exchange two old
windows with an area of 3 m
2
and the total window area of the building is 20 m
2
,
then you exceed the 10 % threshold and thus have to comply with the EnEV
requirements.
