Tuesday 18 October 2011

The Passive House: A method rather than a building style (author: Dr Wolfgang Feist)

The Passive House standard is a universal standard for the construction of low energy buildings. The Passive House standard can be adapted for different regions throughout the world. Although regions might have differing climates, the principles of passive house will remain the same.

The main aim of the Passive House is to reduce living costs through energy efficiency, and to create a comfortable, efficient, living environment. The standard specifies that the peak heating load is not to be above 10w/m2. This is because below this level the mechanical heat recovery ventilation system (MHRV) can be simplified and used as space heating, thus reducing costs as a separate heating system is no longer required. The MHRV’s function is also to maintain good indoor air quality.

Achieving a heating load of 10w/m2 will be relatively easy in a warmer climate, but would need more consideration and planning in a colder climate. Achieving a “Zero Energy House” is not as desirable in economic terms, as the investment needed to increase construction standards to zero energy is much greater that the return on investment in the operation of the building. Also the environmental impact of a Passive House is so low as to be considered negligible.

Some rules of thumb:


  • Comfort should be considered. A good indoor climate can easily be achieved using the standard.

  • Simpler affordable solutions in relation to present building practices should be used.

  • It is acceptable to minimise energy demands using conventional sources rather than aim for a “Zero Energy House”

  • Insulation is recommended in all climates.

  • Shading is needed in all climates that have high levels of solar radiation.

  • Heat recovery is needed in all climates. This is also needed to maintain comfortable indoor air-temperatures and humidity levels.

  • Using very low energy MHRV systems is very important.