CHICAGO — Passive House Institute US (PHIUS) and Fraunhofer Institute for Building Physics (IBP) have announced the release of WUFI® Passive 3.0, an advanced passive house modeling software tool. With this major update, a no-cost version of WUFI® Passive will be made available for download. 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 at

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

To prevent moisture problems in passive house concepts with superinsulation and very tight building envelopes, WUFI has become a useful tool to passive house designers. For that reason, in 2013, Fraunhofer IBP, PHIUS, and Owens-Corning Corp. 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 ensure long-term moisture avoidance at the design stage. Both the dynamic and the static modules of the software have been improved and extended in this first major upgrade.

“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 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.”

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Publication date: 6/22/2015

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