Thanks for all the Passivhaus comments, and apologies for the group response. I Think my comments have been misleading and, perhaps, deliberately provocative. I think too, that you’re right – Passivhaus works and is perhaps THE appropriate standard for UK new build – certainly while there’s not a real alternative. I do believe my piece raised a key point though, though, but I think it is the margin of the conversation, not the main part and perhaps a distraction.
One off new builds in rural locations are not the main part of the conversation – the main conversation, of course, is what we aspire to do with housebuilding generally – and certainly I do believe Passivhaus approach is a good one here – particularly when the alternative is greater heating demand or primary energy use. The Code for Sustainable Homes has proved to be hollow – focussing on the wrong issue of theoretical carbon emissions, not actual energy use. So, categorically, I agree wholeheartedly with Passivhaus that the standard must be about energy demand.
So – I’m with you here, and I’ve only really had one key point (it’s a a fringe point, really) which concerns more particular buildings which have a more complex relationship with a site or use (the houses I’ve talked about). Yes, these buildings need to focus on actual energy use too, but I’m not convinced that heat recovery whole house ventilation systems would have been appropriate. That was my rather clumsy ‘one size fits all’ comment. But even so, all of those houses used core Passivhaus principles of orientation, insulation and efficient envelope, so I’ve never been a non-believer. The thing is, it doesn’t really matter too much if these houses aren’t certified.
There’s another point of not being convinced of using the Passivhaus standard in warmer climates – I’m a big believer in natural ventilation and thermal mass, still. But again I’m happy to be proven wrong.
Finally, I think it is this point – of wondering if natural ventilation (with thermal mass, of course) can still have a place in the UK – for some of the year (and the whole symbiosis with site thing) that has made me waver whether full Passivhaus certification is always appropriate. Maybe it is, and the answer, of course, is that the occupier has free reign to operate a building accordingly when he or she sees fit, and not when they don’t…
I suspect too, that my previous post was also provoked by the seemingly hallowed-and-beyond-reproach nature of Passivhaus, and I’m a big believer in prodding, poking, and turning inside out.
The big focus, though, has to be on raising the standard of the 95% of housing from the volume house builders that has zero design aspiration – Taylor Wimpey, Persimmon, Barratt, David Wilson – you know who they are – and, with this, if a first step was convincing them to begin adopting Passivhaus, it would be a great start, irrespective of ultimately whether Passivhaus is flawed in dealing with the particular or not.
Keep up the debate.
5 Comments
Piers, it was an interesting debate and thanks for raising it. As to the ventilation issue, I’ve always thought of it like this. if you want to use natural ventilation, (opening windows and doors) you can. There may be an ‘energy’ penalty, either heat loss or heat gain depending on external conditions. Of course this is also true in a ‘normal’ house. In a Passivhaus it may take longer to recover from it, but it remains the occupants choice. In practice, the penalty isn’t normally that great, and users soon instinctively understand it. The main point though, is that when external conditions mean it’s inadvisable, then you have an alternative, which you generally don’t have in a ‘normal’ house. I don’t believe the certification issue has any bearing on any of this. Certification is really just a good QA system, and limits the misue of the Passivhaus terminology, but in the end it’s just about energy and comfort.
Agree with Chris re certification, see article here on what it means to claim a building is a PH http://www.elementalsolutions.co.uk/books-and-free-downloads/building-and-energy/
PH+ magazine is very high quality and encourages warts and all sharing of results. Shame you missed the UK Passivhaus conference, plenty of warts and all sharing and plenty of questioning all aspects of Passivhaus in a very robust, open and humourous way.
Nick
I agree with Chris on this; thanks Piers, and I really would like this kind of debate to continue. It aids the understanding of Passivhaus as a methodology (rather than a standard) and also helps us to push Passivhaus in different directions that may make its application even more useful to the UK and a wider audience.
Great debate on twitter and here, well provoked Piers! 🙂
I second Chris’s comment – when we design buildings to the PH standard, we also design them to work fully with natural ventilation. (Thermal mass plays a small role too, but it is very minor when a building is well insulated in the UK climate.) We offer the end users education in running the building and fully expect that the mechanical ventilation system will be switched off outside of the heating season, unless the users see some specific reason to run it.
Personally I believe every innovation with environmental credentials has its place in modern architecture. The question I want to rise is how far do we have to go with gadgets, super windows and other effective but consuming large quantities of energy and environment while manufacturing innovations? Passive house is good in certain places at certain times while perhaps simpler solution would be more effective somewhere else. Would I really go to all the effort of building super passive house? Some would say, it would stay for 100’s years, I would say, technology and architecture like fashion are changing too quickly… When we plan the house, we should take into account our needs only! And life span on not more than 100 years… and think about its environmental impact when dwelling no longer needed.