Lisa White, PHIUS Certification Manager
Certification Update: PHIUS will not accept PHPP v9 for PHIUS+ 2015 Project Certification
Up until now, Passive House Institute US (PHIUS) has allowed project teams pursuing PHIUS+ Certification to use one of two passive house modeling tools to model their projects: 1) WUFI® Passive, the passive building modeling software developed by Fraunhofer IBP in collaboration with PHIUS and Owens Corning, and 2) Passive House Planning Package (PHPP), the passive house modeling tool developed by the Passivhaus Institut (PHI). However going forward PHIUS will not be accepting the latest version of PHPP v9 for PHIUS+ 2015 project certification.
Since the release of the PHIUS+ 2015 Passive Building Standard in March of 2015, PHIUS’ standard now differs significantly from the PHI standard. Specifically, the PHIUS+ 2015 Standard uses climate-specific targets for space conditioning energy use (the first such passive building standard to do so), limits overall energy use for residential buildings on a per person basis (rather than a square footage basis), and now uses a different metric for air infiltration.
For the first six months after the PHIUS+ 2015 Standard went live, project teams could elect to pursue either the earlier PHIUS+ Standard or the new PHIUS+ 2015 Standard. All new projects registered after September of 2015 are required to pursue certification under the PHIUS+ 2015 Standard.
Modeling Tools for Certification
Since the release of WUFI Passive in 2012, PHIUS has stopped teaching PHPP software during Certified Passive House Consultant (CPHC®) training and began exclusively teaching passive building energy modeling with WUFI Passive. PHIUS has since trained over 1,100 building professionals in the WUFI Passive software to date. In conjunction with the release of the PHIUS+ 2015 Standard, Fraunhofer released WUFI Passive v3.0, which includes a “PHIUS+ 2015 mode”. This software is uniquely suited to PHIUS+ 2015 projects, the North American passive building market, and is available for free on the Fraunhofer website.
Previously, project teams could use either WUFI Passive or PHPP for PHIUS+ project certification, and PHIUS continued to accept both modeling tools even after the release of the PHIUS+ 2015 standard. However, this was not without extra effort from the PHIUS project reviewers, as each PHPP submitted for PHIUS+ 2015 certification required a bit of “jury-rigging” in order to verify compliance with the PHIUS+ 2015 Standard. This adds time, and likely an extra layer of confusion, to the certification process.
In October 2015, the PHI released PHPP v9. While this new software offers a variety of updates and new calculation protocols, PHIUS feels this software is no longer appropriate to verify compliance with the PHIUS+ 2015 Standard. As these two passive building standards diverge, the verification software also suitably continues to diverge. This ultimately does not come down to which software is “better”, but rather is simply about which software tool is most appropriate for each standard.
PHIUS will continue to accept earlier versions of PHPP for PHIUS+ 2015 certification, from the “06-02-10” IP overlay of the 2007 PHPP up through PHPPv8.5, but will not accept PHPP v9 for PHIUS+2015 certification. Eventually PHIUS will only be accepting WUFI Passive for modeling of PHIUS+ 2015 projects, but the date for this has not yet been determined.
For project teams with completed PHPPs that would like to transition over to WUFI Passive, PHIUS is offering a new service for a “one-time conversion” of your project from PHPP to WUFI Passive. The flat fee of $1000 for this service also includes the creation of a SketchUp file for the building and a walk-through of the completed model with PHIUS Certification staff. Contact firstname.lastname@example.org for more information.
If you are a CPHC who has been meaning to venture into the world of WUFI Passive, PHIUS offers WUFI Passive training programs at various locations throughout the year to help get you up to speed on creating your own models in the software. Visit the WUFI Passive Training page for more information and to register for upcoming trainings.
Lastly, keep in mind that modeling tools are a small (albeit integral) part of the big picture. Try not to lose sight of the overall goal, which is to build energy efficient and resilient buildings that help to reduce the carbon footprint of the built environment. Regardless of your program preference, every step toward these goals is a step in the right direction.
 PHI allows project teams to pursue certification under previous iterations of their passive house standard as well as earlier versions of PHPP. However PHI’s new PER metric (the PE metric was used previously) requires using PHPP v9, the only version of the software able to calculate this. Thus PHPP v9 is not yet required for all projects; a sunset date for older versions of the standard and software has not yet been determined. For more information, see the “Criteria for the Passive House, EnerPHit and PHI Low Energy Building Standard” document on PHI’s website.
About WUFI Passive
WUFI Passive is a powerful modeling program that dramatically improves the quality and efficiency of the passive building design process for Certified Passive House Consultants (CPHC®). The software allows for calculation of both static passive building energy modeling, as well as dynamic energy modeling for comfort and hygrothermal analysis. The user-friendly interface allows for SketchUp & Revit import, incorporates a seamless toggle between SI-IP, and generates high quality results reports for communication with clients and the PHIUS Certification team. Learn more at the WUFI website.
About the PHIUS+ 2015 Passive Building Standard
Developed in cooperation with Building Science Corporation under a US Department of Energy grant, the PHIUS+ 2015 Passive Building Standard is the first and only passive building standard based upon climate-specific comfort and performance criteria aimed at presenting an affordable solution to achieving the most durable, resilient, energy-efficient building possible for a specific location. PHIUS+ 2015 is also the only passive building standard on the market that requires onsite QA/QC for certification.
Buildings designed and built to the PHIUS standard consume 86% less energy for heating and 46% less energy for cooling (depending on climate zone and building type) when compared to a code-compliant building (International Energy Conservation Code IECC 2009), resulting in an overall site Energy Use Intensity (EUI) of approximately 10-20 kBTU/ft2 year.