The impetus for my journey to Frankfurt, Germany in April was the 17th International Passive House Conference. As I walked toward the venue it occurred to me that this is my 10th anniversary at that event…
…and that we’ve come a long way on this side of the pond. It looks like we might be able to match participation this year at our upcoming 8th Annual North American Passive House conference in Pittsburgh. Overall participation in Frankfurt, according to the distributed participants list, was 650 people.
Ninety exhibitors were on the exhibit floor. Among those were quite a few very large companies such as Saint-Gobain and Sto, who have embraced passive building solutions. One company struck me as especially interesting for the U.S. market: Compacfoam. They offer very simple thermally broken solutions using their compressed and structurally stable foam product. Those work for window installation, thermally broken point connections of curtain wall facades, point connections for balconies or porches attached back to the house structure as well as for the insulation of window frames. Those solutions could easily be implemented in the United States. All we need is the material.
Overall on the trade show floor, the innovations seemed to have leveled off some. In many cases the innovations presented were refinements of an already existing product. This is rather good news as it signals that passive in Europe has truly become mainstream. The smaller numbers of participants and exhibitors at the conference can be explained that way as well: other larger more general building conferences have absorbed the topic and are offering equally qualified information. Passive building is everywhere!
Some significant updates from the passive building modeling front: This year, only one year after the last 2012 PHPP update came out, a new 2013 PHPP version has been published. Word is that the PHI significantly improved the cooling demand and latent load algorithms to be more appropriate for hot and humid climates. A new latent demand annual budget had already been included in the overall cooling demand certification criterion for 2012.
Newly unveiled to the European market (it was released earlier here in the States) at the conference: WUFI Passive developed by Fraunhofer IBP. The new passive modeling tool — that in addition to just a static calculation method also includes hourly dynamic simulation capability and hygrothermal assessment — was presented to the worldwide passive building community. Overall it was good to see that everybody in the field is working diligently on passive modeling tools that are accurate for all climates including the more challenging hot and humid ones.
Back to the PHPP update: be aware that if you still use the older versions of PHPP (2007 through 2012) for your passive designs, it is very likely that your results may not be as accurate as they could be. You should consider upgrading. If you are working in more complex and challenging climates (very cold climate zones starting at 8 as well as mixed humid, hot humid, hot and dry climate zones, plus all zones with very high solar radiation) PHIUS very strongly recommends to use a dynamic model in addition to PHPP (or to use WUFI Passive which does both calculations — passive static verification and dynamic modeling).
Some caveats: The stated improvements/changes in the algorithms in PHPP 2013 are a great step – it marks an acknowledgement that cooling latent issues were indeed not properly addressed until now. But, these changes for cooling and latent have not yet been verified in the various North American climates. Moreover, with more built examples and data now available, the larger question is: How accurate can a limited static representation relying only on monthly climate data really be? It is very likely that it does not afford enough granularity to accurately predict very complex interactions of buildings with a multitude of climate factors.
For those more complex climates with heating, cooling, latent and solar climate factor combinations dynamic modeling appears to be quite a bit more accurate, allowing designers and consultants to limit the inherent risks in modeling: under or over-predicting performance as well as verifying that comfort conditions are assured throughout all rooms and spaces.
PHIUS is not alone with this recommendation of combining a dynamic model with a simplified static one for the best results. Belgium, the country that recently made the news with its decision to make Passive Standards code by 2015 for all new and retrofit construction projects, also requires all designers to back up the static passive house model with an additional dynamic model! Hence, the Belgian representatives of the Plate-forme Maison Passive I met with in Frankfurt were very interested and excited to learn about the advent of WUFI Passive.