Recently, I had the opportunity to meet Richard Hawkes, whose very attractive house Crossways appeared on an episode of Grand Designs last year. His project has just gained Passivhaus certification, which is great. Congratulations!
When I met Richard and on his blog, he expressed his belief that the PHPP is a block to creating "joyous" buildings and, now that he has certification, that the PHPP is redundant. Indeed, the PHPP seems to be generally a Bad Thing; as well as interfering in the creative process, it is antithetical to collaborative working.
I am amazed that the PHPP, which is after all just an Excel spreadsheet, albeit a very sophisticated one, has such power over architects, builders and others working in the built environment that it can prevent them from producing beautiful designs or working collaboratively. My experience as the client and Passivhaus designer during the design phase of our project does not bear this out. We have found the PHPP to be a very useful tool in helping us to optimise our design, for instance by not over spending on unnecessary insulation or by focussing our attention on detailing critical areas correctly. However, the PHPP does not design the building for you. It is still up to the architect to use their creativity and experience to deliver a building that uplifts, that is "joyous". It is still essential to work collaboratively on the project, indeed collaborative working between client, architect and the builder (who should be identified and involved early in the project) is probably the most important success criterion in a Passivhaus project. The PHPP is merely one of the tools in the design tool-kit.
We have been more constrained by other factors, primarily by the fact we are refurbishing an existing property, rather than building from scratch. Also, our house is on an estate with a strong architectural character and it is this, other site constraints, financial constraints and the requirements of the planners that are driving our design, not the PHPP!
I think that Richard is right when he talks about experience. The Passivhaus design process uses a lot of rules of thumb, derived from many years' collective experience, to get the initial design broadly correct; this is something that an experienced, certified Passivhaus Designer can bring to a project. Having produced an initial draft of the plans informed by those rules of thumb, the PHPP is there to help to highlight potential problems in the design. It is still up to the architect, Passivhaus Designer, client and builder if they want to aim to use the PHPP to achieve Passivhaus certification. They may decide that a particular aspect of the design is more important than reaching the full certified Passivhaus standard. Using the PHPP properly means this decision is a concious one, rather than an unintended error. In that scenario, the PHPP can sometimes help identify other areas where the shortfall can be made up elsewhere in the design. In a world where Passivhaus design is the norm and understanding of Passivhaus design and methodology has been widespread for decades and is embodied in the DNA of all the professions working in the build environment, the PHPP would probably become considerably less useful. However, particularly here in the UK, where we are very far from this, the PHPP will remain a useful tool for a long time.
I would add that in a refurb, where nearly every project needs a bespoke design, the need for the PHPP is even greater. In a new build, provided that client, architect and builder have that "Passivhaus DNA", whether or not they would recognise it as that, and particularly in the less challenging (meteorological) climate of southern England, Richard Hawkes has shown that it is possible to reach certification. However, I wonder whether he could not have trimmed some elements of his design* and saved himself a bit of money by using the PHPP tool earlier on.
* I am referring to those relevant to the building's energy performance, not those that make it "joyous"
[edit 27 Jul] This recent article on the Centre for Alternative Technology's new WISE building continues the debate.