Beyond LEED AP: Lessons From Certified Passive House Consultant (CPHC) Training

Beyond LEED AP – A recap from Certified Passive House Consultant (CPHC) Training

Last month, Weber Thompson sent Aaron Swain and I to take the Certified Passive House Consultant (CPHC®) training from the Passive House Institute US (PHIUS). As active members of the WT Sustainabiliteam, with strong personal interests in reducing our ecological footprints, we see a lot of value in the Passive House methodology because it sets a proven path to achieve ambitious, yet obtainable, energy efficiency goals.

Weber Thompson's Pike Passive project - a new, 42-unit apartment building in Capitol Hill
WT’s Pike Passive project – a new, 42-unit apartment building in Capitol Hill

The training was timely because the new PHIUS+ 2015 Building Certification Standard is the first passive house standard applicable to North American construction. While Passive House strategies have been embraced by European builders for many years, this new standard has inspired a new, rapidly growing Passive House movement in the United States. One of the exciting new projects in the pipeline is Weber Thompson’s own Pike Passive project in Seattle – a new, 42-unit apartment building in Capitol Hill for 13Pike LLC, a development partnership between Barrientos + RYAN and Cascade Built. Currently under construction by Cascade Built, the project is currently on track to be one of Seattle’s first Passive House Certified mixed-use, multifamily projects.

Originating in Germany, the Passive House building standard’s underlying premise is to build with an envelope so tight and well-insulated that one could “heat the home with a candle.” While this is a lofty goal, the energy efficiency metrics Passive Houses have achieved are impressive, consuming 60-85% less energy than comparable code-compliant buildings[1]. While the concept of an air-tight envelope paired with continuous insulation is simple enough in theory, in practice these two things must be carefully thought out, modeled and coordinated in every construction detail.

Energy model constructed in WUFI

The CPHC training was a week-long intensive program on the strategies used to achieve this performance, which included strategic solar orientation, high-performing windows, carefully calibrated ventilation, and high-efficiency lighting, appliances and HVAC. We studied the important role these components play in reducing the heating, cooling and ventilation loads of the building using a computer modeling program called WUFI to construct an energy model that quantified the total energy consumption of the building. We also delved into the energy performance implications of a variety of construction details, by reviewing the building science behind the design of various assemblies and used a computer modeling program called THERM to model the thermal bridging and moisture risk of specific conditions.

One of my key takeaways from the training was that the energy performance value of Passive House strategies is less about purchasing the highest end assemblies, systems or components, but lies in an added level of care for the coordination and study of the performance of each detail. At the end of the long week, Aaron and I returned with a new toolset to enhance the capabilities of our firm. I believe we will see a lot more of Passive House projects in the near future, and in the meantime this skillset can be broadly applied across all of our high-performing work here at Weber Thompson.


– Emily Doe, AIA, LEED AP BD+C

Emily DoeEmily is an Associate and Project Architect at WT with over 10 years experience. She brings a dynamic and detail oriented work method to all phases of design from pre-design through construction administration. She also uses her skills on a variety of project types including mixed-use and multi-family.

Learn more about Emily on our website.

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