Passive House projects are at the forefront of a transition in the AEC industry, as high performance building standards are becoming increasingly popular.
In this post by CopelandBEC consultants Gert Guldentops and Autumn Dean, you will get a crash course introduction to Passive House.
Passive House is a performance-based certification rooted in the principles of building physics and administered by the Passive House Institute US, or PHIUS.
The ultimate goal of Passive House is to reduce energy consumption, improve durability, and enhance occupant comfort, be it for high-rise buildings, academic facilities, or single-family homes. This is accomplished through three main strategies:
- Thermal control to limit heating and cooling loads through passive measures (e.g., high performance windows, continuous insulation, ERV/HRV systems)
- Airtight construction to prevent convective heat loss and avoid moisture issues (e.g. comprehensive air sealing, balanced ventilation)
- Solar radiation optimization to balance heat loss and gains (e.g. climate-specific building orientation, shading measures)
- Limits on heating and cooling loads for space conditions that incentivise passive energy conservation measures (e.g., high performing windows, efficient mechanical systems, etc.).
- Source energy limits that encourage use of efficient equipment that meet reduction targets with a “conservation first” goal.
Passive House standards result in highly efficient and resilient buildings that consume 40-60% less energy than their code-minimum counterparts. Beyond energy targets, Passive House strives for long-term durability by implementing several moisture management measures throughout design and construction. Passive House also leverages improved indoor air quality and thermal comfort to prioritize occupant wellness.
Passive House Standards
PHIUS offers multiple building standards to accommodate different building types and project goals. The two primary standards are PHIUS CORE and PHIUS ZERO:
- CORE is the legacy standard that focuses on optimizing the design through either energy modeling using WUFI Passive software or by adhering to a prescriptive checklist. Only single-family and townhomes are eligible for the prescriptive checklist, while all building types can be certified using the performance-based pathway.
- ZERO builds upon CORE by requiring renewable energy to offset the building’s energy use and excluding the use of fossil fuels. This standard can be applied to all building types and does not offer a prescriptive path.
A common misconception about Passive House is that it’s only applicable to single family homes, but there are actually CORE or ZERO pathways available for all building types and scales, including retrofit projects.
Several states and municipalities – including New York, Denver, Massachusetts, and Washington – now allow Passive House standards to serve as an alternative pathway for building code compliance, further increasing incentives for adoption.
Project Team
A successful Passive House project relies on several key experts:
- Certified Passive House Consultant (CPHC) – CPHCs are responsible for WUFI Passive building energy modeling, the enclosure design (with an emphasis on thermal control, air control, and moisture control), and coordinating the mechanical systems with the project’s MEP engineer. They play a critical role in guiding projects through the Phius certification process, from initial design to final construction.
- Certified Passive House Builder (CPHB) – CPHBs are construction professionals specifically trained in passive building. While Passive House projects are not required to be built by CPHBs, engaging builders with this credential further supports the success of a project.
- Certified Raters and Verifiers – Raters and verifiers conduct on-site inspections and performance testing throughout construction to confirm that the building is in compliance with Passive House standards. Raters oversee residential projects, while verifiers commission commercial (non-residential) projects.
- PHIUS Staff – staff from PHIUS provide guidance and compliance oversight throughout the lifespan of the project.
Passive House Consulting
CPHCs can provide several services over the course of a project to elevate projected performance and fulfill the Passive House requirements:
Concept Phase:
- Coordinate the integration of the construction team early in the design process to review the passive house process and requirements.
- Assist or lead design charettes to facilitate the development of conceptual or schematic designs.
- Identify high-level goals and challenges related to building science and desired project outcomes.
Schematic Design to Design Development Phase:
- Study the feasibility of Passive House certification for a concept design through a peer review of the drawings and a preliminary WUFI Passive model to gauge compliance and offer recommendations for success.
Design Development to Construction Document Phase:
- Perform Passive House energy modeling to compare design options and confirm the design is on track to meet the compliance criteria.
- Review or assist in preparing design documents for building enclosure systems, confirming the design will meet all prescriptive requirements and conforms to the energy model.
- Analyze building enclosure details to determine thermal performance (U-factors, SHGC), thermal bridging (psi-values), and condensation risk.
- Coordinate with the mechanical engineer to establish heat/energy recovery ventilation, space heating, and space cooling systems.
- Collect documentation for project precertification at the end of the design phase.
Bid and Negotiation Phase:
- Participate in pre-bid meetings to present the Passive House certification process and respond to bidder questions related to Passive House certification requirements
- Review bid proposals and confirm Passive House scope items are accurately captured in bid proposals
Passive House certification requires a deep understanding of building science, energy modeling, and meticulous coordination across disciplines. By integrating Passive House principles early in the design process and maintaining rigorous coordination throughout construction, project teams can achieve superior energy efficiency, durability, and occupant comfort.
More Passive House
This post is part of a Passive House series. Be sure to check out Passive House: Bringing Passive Building into the 21st Century and Passive House Certification: A Practical Guide to Staying on Course as well.
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