Heading to Frankfurt International airport with a handful of Passive House pilgrims from across the globe, a week in Darmstadt, Germany, has been anything but passive.
The 20th International Passive House Conference of 2016 has allowed this novice an insight into the truly remarkable world of Passive House Design.
From the concluding thoughts from the godfather of Passive House design, Dr Wolfgang Feist, I can only surmise that the Passive House movement is in very safe hands, expanding to warmer climates and fast becoming the benchmark for high performance/low carbon design.
A Brief History of Passive House
Back in October of 1991, the keys to the first Passive House homes in Kranichstein, Darmstadt, changed hands in a building not far from my hotel for the week. For the past 25 years, this air-tight, highly insulated and well-built concept has been continually put to the test as the home of Dr Feist himself!
While a definition of Passive House is likely to have been around upon the completion of the Kranichstein project, today we state that “a Passive House is a building in which thermal comfort can be guaranteed by post-heating of post-cooling the fresh-air flow for good indoor air quality without additional recirculation”… A bit of a mouth full, I know!
What it means, in essence, is that a building is provided with ventilation to facilitate human occupation, and that minimum rate of ventilation must be able to deliver the heating demand. Any increase from this level would affect efficiency and, most importantly, other comfort factors such as air movement (drafts) and dryness of the air.
With measurements of average heating energy consumption recorded around 9kWh a square metre a year, Kranichstein is now seen as a testament of stability and even today, its exceptional performance is still six times better than the latest requirements for new buildings in Germany.
Indeed, given the savings generated over the course of its 25 years of occupation and measurements, it could easily gain the title of the most energy efficient building in the world.
To celebrate its 25th birthday, Kranichstein has now been crowned with a brand new photovoltaic array, reducing its primary energy balance further to meet the new Passive House Certification, Passive House Plus.
Beyond the ubiquitous suppliers of triple glazed glazing systems – now adopted in as much as 80 per cent of all German new builds, the Passive House Institute tells me – the conference topics aimed to test the passage of time to systematically question the durability of components for building envelopes and services and the resileance of Passive House design.
Do buildings that are built air-tight remain air-tight? Has long-term and multi-climate experience in the operation of real-world projects revealed unknowns around moisture and hygiene risk? Is Passive House suitable for non-residential buildings from an investment point of view?
Using the backbone of the Passive House certification process, an energy modelling tool called the Passive House Planning Package, more than 110 presentations answered and sparked debates about these and many more topics, Illustrating an unparalleled focus in the detail of building physics and design.
In many cases, between 70-90 per cent of direct energy reductions against typical build quality were proudly displayed, supported by incredible levels of annual thermal comfort and design.
The lucky countries
And it wasn’t just the cold climates of Northern Europe, Scandinavia and North America to dominate the discussion. Warm climates or “lucky countries”, as they are known in the PHI (citing Donald Horne’s The Lucky Country, shared part of the discussion.
With case studies from Greece, Spain, Portugal, Italy, Turkey and Australia, early movers in the Passive House space tempted the audience into the lesser known world of summer design strategies and new markets.
How do we deal with heat waves and meeting the challenge of overheating? Is the PHPP design tool tested and sensitive to our warm climate? How do you get construction teams to not only learn, but embrace the change necessary for the delivery of truly high performance design? Are Passive House and LEED competing or complementary? Can I procure the construction material suitable for Passive House Certification? Many challenging, but none insurmountable.
While the representation amongst the 80,000 ongoing and completed Passive House projects are likely to be thin on the ground, the rate of adoption is still impressive, often in counties that are still recovering from the economic fallout of 2008.
China goes passive
Of the many detailed discussions and visual spectacles at the conference, the representation of Chinese delegates were second to only the Germans. The session, China goes Passive, presented current and future trends were typically impressive Chinese statistics.
With zero projects five years ago and no market experience, nine projects are now certified, 70+ of many typologies are ongoing. With some projects being typical of a larger home in Europe, around 150 sq m, others are as large as 40,000 sq m.
Over this same time period more than 100 Chinese designers and consultants have been trained by the PHI affiliated partners while 23 are now certified. Ten Chinese-made local windows and curtain wall systems have now been certified by the PHI under its strict Component Certification program (it can take up to a year to certify). The Chinese government also recently announced another 100,000 sq m of Passive House buildings to be delivered in the coming years, so momentum is building.
With no room to sit in the China-focused workshops, the expectation is clearly high for Chinese product and expertise development, as this will impact the viability and affordability of new and establishing markets across the globe!
The Cost Challenge
Passive House is a hugely diverse beast and varies not just region to region, but client to client. So far, the standard has ticked off numerous construction methodologies, with this year’s presentations focusing on solutions from typical precast concrete to strawbale. Partly for this reason, it is extremely difficult to pin down the precise ‘cost’ of Passive House, but experience is now telling us what’s possible at or below typical build cost in many areas.
In the colder climates off Canada, evidence suggests that pre-fab can be achieved on remote sites for less than the cost of an on-site build, as well as on social housing projects. Additional costs for Irish retrofit projects come in at a modest 9 per cent even with a number of unforeseen problems on site. Architype, from the UK, demonstrate time and again that school projects can be achieved on standard budgets, and sometimes less.
Closer to home, at this year’s South Pacific conference in Melbourne, New Zealand projects claimed to be also making some ground in lower-cost applications.
It would seem that the idea that Passive House costs more is being truly tested on an international scale and many are accepting the challenge. With the extensive development of products and experience in China, this will no doubt assist the cost of projects in that region, Australia and further afield. While capital costs are important, it should also be noted that this is potentially a short-sighted view without the inclusion of costs associated to comfort, health and wellbeing, carbon emissions and global warming.
Partners of the Passive House movement now include (among many) the UN, the EU and numerous high profile partners including the Cities of Frankfurt, Vancouver, Brussels and New York, with these cities now entrenching Passive House in their building codes. Some are seemingly seeing the value proposition of Passive House far more clearly than others.
A Future in Australia
In Australia, while we only have six officially Certified Passive House projects, there are dozens underway that promise to double or triple our certified projects in the coming year, and our experience and knowledge to boot. In the coming months, Australia will also have Certifiers based in Victoria, making the process easier and more cost effective than ever.
It would seem that given the rate of adoption and the innate focus on health, comfort and performance, Passive House has a bright future in Australia, a Lucky County where the effort to meet Passive House requirements is significantly less than our European counterparts!
For those interested in local activities, The Australian Passive House Association is a great please to start the journey.
Darren O’Dea is principal building physics (ESD) at Inhabit Group.