Passive house encourages designers to address all aspects of the design at an early design stage, including the types of materials/systems that will be used. A wholebuilding system approach i.e. one where the materials have been pre-selected and developed into a holistic system, can help designers make their design decisions with confidence that the final outcome will meet the passive house requirements. This chapter highlights the key areas that should be addressed when adopting a wholebuilding system approach.
Passive house encourages an approach to design which considers the building as an interconnected whole. Holistic concepts should be applied to the orientation and form of the building, as well as the design of mechanical services and fabric performance. Designers can address all these interconnected principles/requirements through their own work, for example, through their PHPP calculations. Alternatively, there are now multiple companies that offer a ‘Whole building system’ approach to achieving the passive house standard. This may offer a simpler approach, especially for inexperienced designers or clients, as the system providers will have undertaken much of the work to ensure compliance with the passive house standard.
In addition, the systems are built in state-of-the-art factories by highly skilled technicians, which allows for closely monitored quality control without the need for multiple on-site visits during varying weather conditions. However, they may not be suitable for all sites, designs or situations!
All whole-building systems should deliver on passive house requirements, including the following principles:
- Fabric U-value 0.08-0.15 W/(m2.K)
- Air tighness
- Window U-value less than 0.8 W/(m2.K)
- Fresh air ventilation 30 m3/h/person
Excerpt from “How to build a Passivhaus: Rules of thumb”, chapter by Kym Mead, Passivhaus Trust, April 2015.