Certification of terraced houses and semi-detached/duplex houses according to Passive House Institute criteria
With version 10 of the building criteria, these supplementary provisions were integrated into the Building Criteria document: Criteria for the Passive House, EnerPHit and PHI Low Energy Building Standard
For terraced houses there are two alternative ways of verifying compliance with the criteria (in the following the term “terraced houses” also includes semi-detached/duplex houses, i.e. houses that have two units side by side):
- The criteria are met by the row of terraced housing as a whole, whereby individual houses (usually the end-of-terrace houses) can have an energy demand that is slightly higher than the requirements. A collective PHPP energy balance is prepared for the entire row of terraced houses. Alternatively, verification of the area-weighted average values of the results of the individual PHPP calculations for each terraced house may take place. Each homeowner may be given a copy of the certificate and the certification booklet for the entire row.
- Each house in the row of terraced housing fulfils the criteria in itself. For this, a separate energy balance is prepared for each house using the Passive House Planning Package (PHPP). With this method, the end-of-terrace houses usually require a better standard of thermal protection on account of the larger envelope area, while the mid-terrace houses comply with the requirements with a slightly lower standard of thermal protection. After completion of the certification process, each house will receive its own certificate and the certification booklet with the energy balance calculation for each house.
Method 2 makes sense if it is important that each terraced house complies with the criteria individually or if the planning for individual terraced houses of a row is carried out by different parties.
Method 1 is appropriate in all other cases. This reduces the expenditure for planning, implementation and certification because the same standard of thermal protection (insulation thickness etc.) can be implemented and only one PHPP calculation is necessary. Despite this, the energy demand for all terraced houses in total is not higher than with method 2. However, it is important to take into account the usually higher heating load of the end-of-terrace houses when dimensioning the heating system (supply air heating alone may not be sufficient).
The end-of-terrace houses are part of a larger Passive House unit (row of terraced housing) and therefore comply with the Passive House criteria of the Passive House Institute. This case is comparable to an (owner-occupied) apartment in an apartment block that has been certified as a Passive House building. Here too, it is sufficient for compliance with the criteria if the entire building meets the requirements – even though individual apartments might have a higher energy demand when calculated separately.
Both methods were also already admissible in older versions of the building criteria of the Passive House Institute. It is advisable that the chosen method is expressly agreed on and set out in written form at an early stage by all relevant stakeholders.
It is possible to certify one unit/dwelling which is part of a row/terraced housing development. In this case the certification is valid only for that specific unit/dwelling and not for the entire row/terraced housing development. The zoning regulation which applies as a general rule can be found in the section “Boundary conditions for the PHPP calculation” of the Criteria for the Passive House, EnerPHit and PHI Low Energy Building Standard.
As of 04 November 2021