Fraunhofer IBP and PHIUS Release Upgrade of WUFI® Passive Software, Including a No-Cost Version

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The no-cost version can be used to certify passive building in the PHIUS+ program.

WUF Passive 3.0 is the most powerful, user-friendly passive modeling tool on the market.

“We’re thrilled that Fraunhofer has made a free version of WUFI Passive available to the growing community of passive building designers"--Katrin Klingenberg, PHIUS Executive Director

Passive House Institute US (PHIUS) and Fraunhofer Institute for Building Physics (IBP) today announced release of WUFI® Passive 3.0 software, the most advanced passive house modeling tool on the market. With this major update, for the first time ever, a version of WUFI® Passive will be made available for download at no charge. The free version will enable users to model passive buildings for the purposes of design and PHIUS+ project certification.

The no-cost WUFI Passive will not include certain advanced features such as user defined database entries, results export and hygrothermal analysis capabilities for components. Licenses for the fully featured version of WUFI Passive are available for purchase. Both versions of the software are now available for download and/or purchase from the Fraunhofer IBP Web Shop.

“Fraunhofer IBP’s WUFI products have long provided powerful capabilities for identifying and avoiding potential moisture issues in buildings,” explains Hartwig Künzel, Head of Hygrothermics department at Fraunhofer IBP.

To ensure moisture safety in passive house concepts with superinsulation and very tight building envelopes, WUFI has become an indispensable tool to passive house designers. For that reason, in 2013, Fraunhofer IBP, PHIUS, and Owens-Corning Corporation partnered to develop a version that integrates the advanced features of WUFI with the ability to do “what-if” modeling for passive buildings of all types.

This new version of WUFI Passive now couples the static passive house design methodology, and a sophisticated hygrothermal dynamic building simulation tool. It offers instant energy demand calculations for the PHIUS+ certification process and dynamic simulations to guarantee long-term moisture-save and hygienic conditions at the design stage. Both the dynamic and the static modules of the software have been improved and extended in this first major upgrade.

Updates and new features of the static passive house design methodology:

  •     PHIUS+ 2015 climate specific certification criteria
  •     Updated inputs for lighting and plug load calculations
  •     Advanced geometry import options
  •     Exhaust air appliance calculations

Updates and new features of the hygrothermal dynamic simulation:

  •     Inter-zonal airflow model
  •     3D-thermal-bridge calculation
  •     Parallelization for improved simulation performance

“We’re thrilled that Fraunhofer has made a version of WUFI Passive available at no charge to the growing community of passive building designers. Experienced designers will love its professional, user-friendly interface and advanced features, while new users will experience a much shortened learning curve,” said Katrin Klingenberg, PHIUS co-founder and Executive Director.

“We wanted to make WUFI Passive’s powerful modeling capabilities accessible to the entire passive building community,” said Florian Antretter, Group Manager of Hygrothermal building analysis at the Fraunhofer IBP. “We also believe it’s a great first step for designers to learn about the range of advanced features available in the full version of WUFI Passive.”

Visit the WUFI-Site ( for more information on WUFI Passive and the entire line of WUFI products.


PHIUS is a 501(c)3 organization committed to making high-performance passive building the mainstream market standard. PHIUS is the leading North American provider of professional training for architects, construction professionals, and quality assurance professionals. Through its PHIUS+ project certification program, PHIUS provides design review and certification and quality assurance of passive building projects. PHIUS also the leading passive building research organization in the United States. In partnership with Building Science Corporation (BSC) under a U.S. DOE grant, PHIUS recently completed a study produced a new, cost-effective and climate-specific passive building performance standards. In addition to the DOE and BSC partnerships, PHIUS has established strategic relationships with RESNET, Carnegie Mellon University School of Architecture, Parsons The New School for Design, University of Oregon, Habitat for Humanity, Rocky Mountain Institute and others.

About Fraunhofer IBP

Building physics is one of the keys to a successful building project. The Fraunhofer Institute for Building Physics IBP focuses its work on research, development, testing, demonstration and consulting in the various fields of building physics. These include noise control and sound insulation in buildings and solutions for improving energy efficiency and optimizing lighting technology. Fraunhofer IBP’s work also covers issues of climate control and the indoor environment, hygiene and health protection, building material emissions, weatherproofing and protection against heat and moisture, preservation of building structures and the conservation of historic monuments.

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