Choosing the design approach
There are many factors influencing your approach to designing a building, including: location and site; your client’s brief, budget, and programme; funding requirements and regulatory standards; and your own design philosophy.
Passivhaus should be seen as one of the fundamental factors influencing design as it cannot be achieved simply by meeting each separate technical standard such as airtightness or window U-values. Passivhaus should become an integrated part of your design approach, underpinning, and even inspiring, all the other factors influencing your design.
To ensure that Passivhaus is integrated into the design of the very earliest ideas, its principles and standards must be understood by all members of the design team.
Key early decisions that may be difficult or impossible to change later – including siting, orientation, building form, and fenestration – have a major impact on the viability and economy of achieving Passivhaus.
It is recommended that the design is modelled using the Passivhaus Planning Package (PHPP) at the earliest opportunity, in order to test and shape these key early design decisions. PHPP should be seen and used as a powerful design tool, helping you to develop your design approach, rather than as a procedure for proving compliance later, when it might be too late.
Explore the impact of the building’s form-factor ratio, the area of external envelope through which heat will escape compared to the area of usable internal building area, and you will quickly discover that whilst almost anything can be made to work, the better this ratio is then the more economic the solution. Aim for a ratio of 0.3 or less.
Test the influence of altering the building’s siting and orientation, or the total and relative quantity of glazing on each elevation, and you will be able to understand the way in which simple environmental principles influence the energy efficiency of a building’s performance. Achieving good design requires not only the solving of a multitude of design challenges, but in the development of creative synergy between them.
Good Passivhaus design requires a fully integrated design approach, out of which an even greater creative synergy can be developed. This will produce buildings that not only meet the client’s brief, and look and feel good, but do actually work with proven energy efficiency and excellent comfort.