This article covers the role of WUFI® Passive in passive house design and how to use cove.tool alongside WUFI Passive in pursuit of a Passive House Institute US, Inc. (PHIUS) certification for PHIUS+.
Our consulting services offer assistance with PHIUS+ certification documentation. Reach out to our sales team to learn more about this support.
What is WUFI®?
The WUFI® family of software, developed by the Fraunhofer Institute for Building Physics, provides realistic simulation for one- and two-dimensional heat and moisture transfer within wall assemblies. WUFI® is an acronym for Wärme Und Feuchte Instationär—which, translated, means heat and moisture transiency. WUFI® software uses the latest findings regarding vapor diffusion and moisture transport in building materials. The software has been validated by detailed comparison with measurements obtained in the laboratory and on IBP’s outdoor testing field. Different versions of WUFI® can be used for materials, components, and entire building systems. Building component simulations (WUFI® Pro and WUFI® 2D) are assembly-by-assembly modeling tools to evaluate thermal and hygric properties across the assembly. Whole building simulations (WUFI® Plus and WUFI® Passive) address the conditions on the interior of the building, as well as indoor climate simulations and energy calculations.
WUFI® Passive is a building energy modeling tool that is part of the WUFI® family of products. It was developed in collaboration with PHIUS in order to create a tool tailored to North American climates and improve the design process for Certified Passive House Consultants (CPHC).
WUFI® Passive brings energy modeling and WUFI’s hygrothermal analysis together in one tool, using both static and dynamic modeling and compatibility with SketchUp and gbXML importing. One of the critical aspects of WUFI® is its ability to move between static and dynamic modeling and the availability of high-quality reporting. It allows users to validate PHIUS+ criteria, and it is the only accepted method for PHIUS CORE 2021 and ZERO 2021 compliance energy modeling
How does WUFI® Passive relate to the Passive House standard and PHIUS?
PHIUS+ is a calculated standard for building energy performance that incorporates quality insurance inspections and low-moisture risk design solutions. This is the leading building performance certification in North America, and the program certifies the U.S. Department of Energy’s (DOE) Zero Energy Ready Home status, the U.S. Environmental Protection Agency’s (EPA) Indoor airPLUS label, and the RESNET HERS Index score as part of the certification.
You can read more about PHIUS, their certification system, and how cove.tool relates to it here.
WUFI® Passive and cove.tool
WUFI® Passive is commonly used for design and validation in pursuit of the Passive House standard, serving as the primary compliance model for PHIUS CORE and ZERO 2021. While cove.tool can complement the PHIUS workflow, we also have internal tools to enable early-stage design evaluation for key Passive House criteria.
After completing early design simulations and evaluations in cove.tool, users can export their project geometry from their preferred modeling software into a gbXML format and import it into WUFI® Passive to validate results that comply with PHIUS+ criteria. Cove.tool can help support early-stage design flexibility and analysis for users using our consulting services, helping users align with PHIUS+ requirements for space conditioning and source energy.
