Passive house Retrofit ENERPHIT Criteria Cork

Architects cork

Certification as “Quality-Approved Energy Retrofit with Passive House Components”
Criteria for  Residential-Use Refurbished Buildings
If the criteria for Passive Houses are met by an energy relevant modernisation, an old
building can also be certified as a “Quality-Approved Passive House”, based on the same
criteria as for new buildings.
Nevertheless, due to various reasons, for older buildings it is often difficult to achieve the
Passive House standard with reasonable effort. The use of Passive House technology for
each building component in such buildings, however, does lead to considerable
improvement in respect of comfort, structural protection, cost-effectiveness and energy
For quality assurance and verification of the specific energy values achieved, buildings that
have been modernised using Passive House components and that do exceed the Passive
House boundary values (for  existing building substance reasons), can receive the
“EnerPHit – Quality-Approved Modernisation with Passive House Components” certificate.
The certification criteria applicable to residential buildings are described below.
1 General requirements
The current certification criteria (to be found at are applicable initially; the
calculation method described in the PHPP  handbook and the PHPP programme are
subordinate to this.
Due to the numerous different requirements and  conditions for the modernisation of old
buildings, it is possible that exact requirements for  individual energy-related measures may
not be included in these certification criteria. In this case, the measures should be carried
out in consultation with the certifier in such a way that maximum energy efficiency can be
achieved, provided that, for the duration of their life cycle, the measures result in a financial
net profit under the normally expected boundary conditions for the building owner and users
collectively.  The thermal protection standard necessary for the building component will be
determined by the certifier in each case.
1.1 Energy balance
The energy balance of the modernised building must be verified using the latest version of
the Passive House Planning Package (PHPP).  This also applies for certification based on
the building component method  (Section 2). For the specific space heat demand, the
monthly as well as the annual method can be applied.  If the ratio of free heat to heat losses
is more than 0.70 in the annual method, the monthly method should be used.
The reference value (treated floor area TFA) is the net living area within the building’s
thermal envelope based on the living space regulations in Germany (WoFIV).
The whole of the enclosing building envelope, e.g. a row of terraced houses or multi-storey
bulding, can be considered for calculating the specific values.  An overall calculation or
weighted average values of several partial zones can be used to verify this.
Combining thermally separated buildings together is not permissible. Buildings that adjoin
other buildings (e.g. in city housing) must have at least one external wall, one roof surface
and a floor slab or basement ceiling in order to certify them individually.
1.2 Time of certification
All requirements for the building  must be met at the time of  issuing of the certificate.
Certificates prior to modernisations that are being carried out in several steps are not being
issued at the moment.
1.3 Restriction to existing buildings
Only such buildings will be certified (EnerPHit certification) for which the continued use of
existing building elements would pose such substantial problems for the energy relevant
modernisation that modernising to Passive House level would  not be practicable or cost
1.4 Location of building
Currently, only buildings located in the cool and  moderate Central European Climate are
being certified.
1.5 Heating demand
QH ≤ 25 kWh/(m²a)
Certification can be issued alternatively if the criteria for individual building components as
given in Section 2 are met.  In this case the requirement for the heating demand does not
1.6 Primary energy demand
QP ≤ 120 kWh/m²a + ((QH – 15 kWh/(m²a)) * 1.2)
The requirements apply to the total sum of the  heating, hot water, cooling, auxiliary and
household electricity.
1.7 Summertime comfort
Excessive temperature frequency (> 25 °C) ≤ 10 %
If calculatig the excessive temperature frequency is not possible due to very high daily
temperature fluctuations, a warning appears in the PHPP “Summer” sheet.  In case of
doubt, other suitable evidence of summertime comfort should be provided.
1.8 Moisture protection
All standard sections and connection details must be invariably planned and implemented
so that there is no excessive moisture on the interior surfaces or in the building component
build-ups.  The water activity of the interior surfaces must be kept at aw ≤ 80 %. In case of
doubt, evidence for moisture protection based on established techniques must be provided.
1.9 Airtightness
Limit value:  n50 ≤ 1.0 h
Target value:  n50 ≤ 0.6 h
The airtightness of the building must be verified using a pressurisation test based on
DIN EN 13829. If the value 0.6 h
is exceeded, a comprehensive search for leakages must
be carried out within the framework of the pressurisation test and each relevant leak, which
can cause building damage and affect thermal comfort, should be rectified. This must be
confirmed in writing as stated in Section 6.2.
1.10 Windows
It is strongly recommended that window frames which have been certified as “PassiveHouse-suitable components”, and triple low-e glazing (or equivalent) are implemented –
using the installation principles
recommended by the Passive House Institute (PHI). If this
recommendation is not complied with, evidence of the comfort according to the conditions in
DIN EN ISO 7730 should be provided or the low temperatures occurring near the window
areas should be compensated for by heaters.
2  Certification according to criteria for individual components
If the specific heating demand of 25 kWh/(m²a) given in Section 1.4 is exceeded,
certification based on the following criteria for individual components is possible instead. All
other general requirements of section 1 must still be fulfilled.
In this case it must be proved that all energy-relevant building components for which criteria
for certification by the PHI for “Passive-House-suitable components” apply, comply with
these criteria.  The criteria for components as published on the internet at
apply, provided that no other arrangements have been made in the EnerPHit requirements .
For products, which have not been certified  by the PHI as “Passive-House-suitable
Components”, the applicant is obliged to provide admissible proof of compliance with the
If there are no products available which comply with the criteria for “Passive-House-suitable
components”, regarding certification for individual cases, in agreement with the certifier, a
product should be selected which complies with the criteria as much as possible.
The required boundary values must be observed at least as an average value
.  Exceeding this value is admissible for partial areas if it can be fully compensated for by better values
Reasonable proof of the thermal transmission resistance (R-value) of the existing building
components must be provided if it contributes more than 5 % to the thermal transmission
resistance of the modernised component.  For  this it suffices to adopt the approximate
thermal conductivity of existing building materials from suitable tables.  If existing building
element structures are not clearly identifiable,  standardised assumptions from component
catalogues based on the construction year can  be used, provided that they appear reasonable.
In the event of an exceptional rule if a standard required specific value is exceeded, suitable
documents should be presented to prove clearly that the conditions for the exception have
been fufilled.
A selection of the most  important boundary values for  components (without claiming
completeness)  and the supplementary regulations for the EnerPHit certification in the
component method have been listed in Sections 2.1 to 2.11 as follows.
2.1 External wall and storey ceiling above outside air
Exterior insulation:  U ≤ 0.150 W/(m²K)
Interior insulation:  U ≤ 0.300 W/(m²K)
deviating from the criteria for “Passive-House-suitable components”
The external wall insulation  must be carried out externally on at least 75 % of the area.
Insulation on the interior of up to 25 % of the area is only permissible if external insulation is
not practicable, not allowed or definitely not cost-efficient.
2.2 External wall to ground
f * U ≤ 0.150 W/(m²K)
with f:  “reduction factor ground“ in the PHPP’s “Ground” sheet
2.3 Roof or top floor ceiling
U ≤ 0.120 W/(m²K)
deviating from the criteria for  “Passive-House-suitable components”
2.4 Roof terrace
U ≤ 0.150  W/(m²K)
2.5 Ceiling of unheated basement
f * U ≤ 0.150 W/(m²K)
with f: “reduction factor ground“ in the PHPP’s “Ground” sheet
If compliance with the thermal transmittance  coefficient given above using conventional
insulating materials(λ ≥ 0.032 W(mK) ) leads to clear room heights of < 2.00 m or to room
heights lower than those specified in the building regulations for the ground floor, the
thermal transmittance coefficient given above may be exceeded as is strictly necessary for
the relevant partial areas, in consultation  with the certifier. For thermal transmittance
coefficients ≥ 0.300 W/(m²K), the maximum possible insulation thickness with an insulation
material conducitivity of  λ ≤ 0.025 W/(mK) should be implemented, provided that insulation
materials suitable for the respective application are available on the market.  Due to
reasons of comfort, the interior surface temperatures of the ground floor flooring must be at
least 17 °C for the design conditions (PHPP: “Ground” sheet, “design ground temperature
for heat load sheet”; indoor temperature 20°C).
2.6 Basement stairs
A continuous space between the heated  area and the unheated basement is not
permissible.  As a rule, either a closed, airtight and insulated door must be present or the
basement must be accessible from outside the thermal envelope of the building (e.g.
staircase from the garden).  The same criteria apply for the enclosing building components
of the basement exit as for the basement ceiling (Section 2.5).
The door between the living area  and the unheated basement must have
UD ≤ 1.60 W/(m²K).
Reducing the insulation thickenss of the enclosing building components of the basement
exit is permissible in consultation with the certifier, if the usability of the basement exit or the
adjacent rooms is unduly restricted.
2.7 Floor slab on ground
f * U ≤ 0.150 W/(m²K)
with f: “reduction factor ground“ in the PHPP’s “Ground” sheet
Because the insulation on the floor slab is interior insulation, it must be checked whether
problematic moisture accumulation can occur in the floor build-up.
If insulation on the floor slab with the required thermal transmittance coefficient is not
possible using conventional insulation materials (λ ≥ 0.032 W(mK) due to practical reasons
(e.g. room height, door lintels), the insulation thickness may be reduced to the level still
possible.  For thermal  transmittance coefficients  ≥ 0.300 W/(m²K), the maximum possible
insulation thickness with an insulation material conductivity of  λ ≤ 0.025 W/(mK) should be
implemented, provided that insulation materials suitable for the respective application are
available on the market. In this case the additional application of an insulation apron around
the floor slab should be considered and if applicable, implemented.
Due to reasons of comfort, the interior surface temperatures of the ground floor flooring
must be at least 17 °C for the design conditions (PHPP: “Ground” sheet, “design ground
temperature for heat load sheet”; indoor temperature 20 °C.
2.8 Windows
Uw,installed ≤ 0.85 W/(m²K)
( ) g W m K ≥ U g⋅1,6 /
The requirements for Uw,installed are considered to have been fulfilled if the average value for
all windows given in the PHPP “Windows” sheet complies with the limit value given above.
If the Uw,installed value for individual windows in living  areas is greater than  0.85 W/(m²K),
evidence of the comfort conditions according to DIN EN ISO 7730 should be provided or the
low temperatures occuring at the windows should be compensated for by heaters.
2.9 External doors
UD,installed ≤ 0.80 W/(m²K)
According to the supplementary sheet, standard values for the recommended installation
situations can be used for the installation thermal bridges if applicable.
2.10 Thermal bridges
The thermal building envelope should not have any linear thermal bridges with
Ψ > +0.01 W/(mK), or punctiform thermal bridges with χ > +0.04 W/K.
This limit value does not apply for thermal bridges which are part of the standard
construction of a building component (e.g. statically relevant dowelling of a thermal
insulation composite system).  These are taken into account in the standard thermal
transmittance coefficient of the building component.
If a thermal-bridge-free detail formation is clearly not economical or  impracticable, the
thermal bridge should at least be diminished as far as economically and practicably
possible, in agreement with the certifier.  Requirements for moisture protection (Section 1.8)
must be complied with in every case.
2.11 Ventilation
ηHR,eff ≥ 75 %
Electrical efficiency of the ventilation system: ≤ 0.45 Wh/m³
All rooms within the heated building volume must  be connected to a supply air and exhaust
air system with heat recovery or be part of a transferred air zone.  Exceeding the criteria for
“Passive-House-suitable components”, ηHR,eff
must be adhered to for the whole ventilation
system, i.e. the heat losses of the warm air ducts in the cool area or the cold ducts in the
warm area should also be included.
Dr. Wolfgang Feist
Rheinstr. 44/46
D-64283 Darmstadt

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