Last edited 28 Jul 2017

Passivhaus

Passivhaus or 'Passive House' is an energy performance standard for dwellings, commercial, industrial and public buildings that can be adopted throughout the world.

It was developed in Germany in the early 1990s by Professors Bo Adamson and Wolfgang Feist. The first Passivhaus dwellings were constructed in Darmstadt in Germany in 1991. It is intended primarily for new buildings, although it can be applied to refurbishment projects, but this can be expensive.

Passivhaus suggest that, 'A Passivhaus is a building, for which thermal comfort can be achieved solely by post-heating or post-cooling of the fresh air mass, which is required to achieve sufficient indoor air quality conditions – without the need for additional recirculation of air.’ This means that a traditional heating or cooling system is no longer essential.

The Passivhaus standard can be achieved by measures including:

Shading.
Pre-cooling of the supply air.
Night purging.
Natural ventilation.
Ait-tightness.
Mechanical ventilation heat recovery (MVHR).
Insulation.
Avoidance of thermal bridges.
Passive solar gains.
Exploitation of internal heat sources.

Whilst Passivhaus adopts the principles of passive design, it differs in its imposition of an overall limit on primary energy consumption. This limit includes; domestic hot water, lighting, projected appliance consumption, space heating, fans and pumps.

The primary energy demand target must be met in all cases, and either the specific heating demand target or the specific heating load target must be also met. In addition, there are limiting values for the performance of the building fabric, doors and glazing, ventilation systems, air tightness levels and thermal bridging. See Passivhaus Outline specification for details.

The energy balance of the proposed building must be verified using the Passive House Planning Package (PHPP).

Certification is available in the UK from a number of organisations approved to assess and issue the Passivhaus Certificate, the EnerPHit certificate (for retrofit projects) and PHI Low Energy Building Certificate. See The Passivhaus Institute.