After Dresden (2010) and Innsbruck (2011), this year’s trip to Leipzig was my third visit to the International Passivhaus Conference organised by iPHA. It is clear that the passivhaus movement has come a long way since my first visit.
In recent years, more EU cities and municipalities have encouraged and adopted passivhaus as a way of meeting ever-stricter energy standards, and Leipzig has also joined this initiative. I hope others will soon catch up with this increasing trend (and congratulations to Exeter for paving the way in UK).
The conference was a great platform to meet old and new friends, put twitter profile pictures against real people and share mutual experiences. After all, it is about people who care and feel passionately about what they do.
With an increasing number of cheaper high-performance passivhaus components hitting the market, it is easier for designers to pick and choose appropriate products, freeing up their creativity. Aluminium clad timber windows can now be specified as slimline 56mm profiles – unthinkable even a few years ago. Emerging in-wall MVHR (mechanical ventilation with heat recovery) units also present an interesting space-saving concept that could change the way ventilation is designed in buildings, particularly in retrofit situations. External walls with passivhaus levels of insulation don’t need to be over 300mm wide – in densely populated areas where space is at premium, wall assemblies as thin as 110mm are now possible.
Designers have never had it so easy, however so much choice can also lead to distractions, so careful evaluation is needed to specify the right products appropriate for each intended use.
Nick Grant’s talk ‘Designing a Better Passivhaus School’ (full paper available here) nicely summarised how simpler design can improve overall performance and reduce costs, (does every school really need BMS, automatic window controls, complex ventilation?). Simpler solutions lead to greater resiliency and durability of buildings, there’s much less room for unforeseen control errors.
Beautiful buildings are also part of the sustainability equation. The best examples of recently completed passivhaus projects, ranging from residential and educational to museums and retrofits, have been selected for the 2nd Passive House Architecture Awards and are free to view here.
New emerging passivhaus classes integrating renewables were presented, these now include Classic, Plus and Premium. ‘Primary energy’, used previously for assessing overall energy consumption, has now changed to ‘Primary energy renewable’ and combines the use and generation of energy. New classes will be available with Version 9 of PHPP (Passivhaus planning package). I understand the political reasons behind the new standards (aligning passivhaus with EU directive for NZEB buildings by 2020), however this may also mean that certain clients will start to demand ‘Premium’, as ‘Classic’ does not sound quite special enough. It will be harder for us to argue that ‘Classic’ is still an excellent and right kind of target to aim for. It should be noted that to achieve Plus or Premium requires not only the addition of a specific amount of renewable energy generation, but also a significant improvement in energy efficiency, through a reduction in primary energy consumption – so these will be tough standards to achieve.
Back in the days of my university studies in mid 90’s I have come across Saskatchewan Conservation House, a quirky-looking building co-designed by Harold Orr. It was a privilege to see Harold being awarded Passive House Pioneer Award by Wolfgang Feist and listen to his humble story of the project. The design focused on high levels of insulation and excellent airtightness. Both these attributes work perfectly to this day, unlike the active solar heating and hot water system that was originally installed for the cost larger than the rest of the house! ‘Fabric first’ approach at its vintage best. What a great and inspiring end to a very intense two days’ event.
On the final day of the conference we visited a number of completed passivhaus buildings – my tour included a new primary school, fire station and a new sports hall built as an extension to an existing listed school building. It’s always fascinating for an architect to look around and analyse someone else’s buildings.
It was interesting to learn that space standards in German schools are two or three times more generous compared to the ones in UK, greatly affecting internal heat gains assumptions. I noticed the relative complexity of shading systems deployed on German schools – motorised external blinds or louvers, linked to light sensors, adjusting the shading according to the position and intensity of the sun. When asked if these worked, our guide said ‘yes, of course, since yesterday!’ so even in Germany they struggle with automated building control systems.
This is quite different to simple, durable solutions we have been developing on our UK schools: brise soleil and roof overhangs, simple cascade ventilation. On the other hand, it was refreshing to see blackboard and chalk in German classrooms – quite a contrast to energy-sapping interactive white boards now mostly used in UK.
Driving back to the UK the following day with Nick, Derrie and Scott, we were digesting impressions of the past few days as we passed huge smoke-belching power plants as well as fields of solar PV’s and wind turbines quietly producing clean power. I felt optimistic that we have the knowledge and options to help shape a better future.
Until next time!