PHIUS+ for Architects & Engineers


The PHIUS+ 2018 Passive Building Standard provides a strong foundation for architects and engineers to build on. Science-based principles, state of the art modeling tools, and a community of excellence and collaboration are some of the many benefits of building to PHIUS+ 2018.

PHIUS+ is simple, straightforward, and applicable to all building types and climate zones

Five necessary criteria guide passive building design regardless of building kind: 1) Continuous Insulation, 2) Airtight Construction, 3) Optimized Window Performance & Solar Gains, 4) Balanced Ventilation with Heat & Moisture Recovery, 5) Tiny Mechanical Systems.

PHIUS+ Certified projects that zero out their source energy demand with renewables are also eligible to receive PHIUS+ Source Zero certification.


PHIUS is the most experienced passive building research institute in North America  

Passive House Institute US (PHIUS) is the leading passive building certification and standard-setting organization in North America. PHIUS has certified and pre-certified over 1 million square feet of passive buildings across 1,200 units nationwide.

PHIUS also provides professional training for Certified Passive House Consultants (CPHC®), Builders, and Raters through in-depth instruction on passive building principles and design, building science, modeling, and ongoing professional development opportunities.

PHIUS has the longest track record of dedication to passive building solutions using North American building science, construction materials, and processes for cost-optimal results.


Climate-based design is the best path to zero energy: for cost and performance

The PHIUS+ 2018 Standard makes passive building affordable by targeting the sweet spot between investment and payback to present a cost-effective solution to achieving the most comfortable and efficient structure possible for a given climate and location, while also offering the best path to zero energy and carbon.

Passive buildings consume so little energy that with the addition of a small renewable energy system they can achieve net-zero or even net-positive levels of performance.


The modeling software is state of the art 

WUFI® Passive is the most potent passive building-modeling tool available. Developed by Fraunhofer Institute for Building Physics in collaboration with PHIUS and Owens Corning, the software is uniquely suited to North America's varied climate zones. The tool is has validated under ASHRAE Standard 140. 

  • It calculates whole-building energy balances
  • It assesses three-dimensional thermal bridges
  • It performs hygrothermal verifications of all envelope components. 
  • It has static and dynamic modes capable of multi-zone modeling for large buildings— beneficial for multifamily projects. 

WUFI-Passive takes the guesswork out of complicated assemblies.


Quality control, assurance, and third-party verification are built-in

PHIUS’ staff has many years of experience in building science, energy modeling, and passive building design. We have reviewed more than 1,000 projects across many climate zones and building types.

Our certification team works collaboratively with your project’s lead CPHC, contributing as another expert team member.

PHIUS+ certification provides the third-party performance verification typically required by energy programs, utilities, and government agencies who offer incentives to passive building.


PHIUS+ is more likely to be understood by local officials

The PHIUS+ Standard is being called the 'next level of high-performance building standards' by the US Department of Energy (DOE) because DOE's extensive climate-based building science research laid the groundwork for PHIUS+ 2015.

PHIUS+ certification requires that projects also comply with DOE-accepted performance practices including the US Environmental Protection Agency’s Indoor airPLUS and WaterSense programs. 

PHIUS+ certified residential projects also qualify for the DOE’s Zero Energy Ready Home program.

By incorporating these programs that are widely accepted by ASHRAE, ICC, DOE, and other Government and professional organizations, we have cleared many of the hurdles perceived to accompany passive building. 


Expert support from the PHIUS Technical Committee

The PHIUS Technical Committee includes leading national and international building science experts and the most experienced passive-building practitioners in North America.

The Technical Committee advises PHIUS and its staff on technical inquiries, testing protocols, standards development, and certification protocols.


A robust community of North American passive building practitioners

The Passive House Alliance US (PHAUS) program is a membership-based chapter organization with over 800 members across 18 regional chapters with dozens of corporate sponsors. PHAUS is a robust support network of passive building communities across North America.

Members can collaborate, share resources, and attend regional meetups and the annual North American Passive House Conference (NAPHC).


Product data on high-performance windows and ventilation equipment

Accurate product data is essential to building precise energy models. To that end, PHIUS has verified the performance of over thirty North American and European windows. The data from each window flows right into the WUFI software, saving time, money, aggravation, and uncertainty.

Information is available in the online PHIUS Product Data Certification database.

PHIUS has also evaluated the efficiency ratings of various North American ventilation units as rated by the Home Ventilating Institute (HVI). We have evaluated residential products as well as Air-to-Air Regenerative Heat Exchangers (AARE) for commercial applications.

PHIUS provides adjusted efficiencies for passive building modeling for these units on the PHIUS website.