“Our mission is to advocate for the adoption of passive house design and construction and high performance buildings in the Austin, TX architectural and building community.”

— Passive House Austin

A Message From Passive house Austin (PHIUS alliance austin) President, Eric Griffin

Austin is an intelligent, thoughtful, vibrant and progressive city that in many ways has lead the nation in local energy efficiency standards and high performance construction. However, engaging the community and creating a Passive House culture in a hot and humid climate has been a challenge. As conventional dialogue for high performance buildings has focused on heating dominated climates with minimal consideration of hot and humid climates with substantial cooling loads, the old Passive House standard was a non-starter for the design and construction leaders in our market. Thankfully, PHIUS released the PHIUS+2015 building standard, which has reinvigorated our chapter. There's finally a climate zone appropriate, economically justified, performance based reason to re-think your perception of Passive House. We all understand that thoughtful design and implementation of building science principles is imperative for successful outcomes for owners and occupants in humid climates, finally there's a Passive House organization that does, too.

What Is Passive House?

Passive House (or Passivhaus in German) is a building standard that focuses on creating highly energy-efficient buildings with minimal energy consumption. The Passive House standard was first developed in the late 1980s by Dr. Wolfgang Feist and Bo Adamson in Germany, and it has since been widely adopted in Europe and around the world.

The goal of a Passive House is to achieve a comfortable indoor environment while minimizing the building's energy demand. This is achieved by optimizing the building's envelope (walls, roof, and floor) to minimize heat loss and gain, while also maximizing the use of passive solar energy. Passive Houses typically achieve this by using high levels of insulation, high-performance windows, airtight construction, mechanical ventilation with heat recovery, and other energy-efficient features.

But to know what it really is, let’s talk about what it isn’t. We need to clear up some common misconceptions: Passive House is not the same as the passive solar building design, although they’re not necessarily mutually exclusive. Passive House also isn’t a house that uses only passive technology. Passive House buildings aren't just houses either. They can be high-rise office towers, multifamily apartment buildings, schools—really any building type.

Simply put, Passive House is the most thoughtful, well organized, science based and performance focused building standard available.

In North America, only two distinct and independent Passive House standards and certifications are available: one administered by Passive House Institute (PHI, based in Darmstadt, Germany) and the other administered by Passive House Institute US (PHIUS based in Chicago, Illinois). The two organizations are not affiliated with one another, however the Passive House Austin group is a subsidiary organization of the Passive House Institute US (PHIUS).

Through most of their early existences, the passive-house standard was similar for both, and you could certify a building with either or both—depending on where the building was located or your personal preference.

Around 2012, that began to change, as PHIUS looked to make performance targets more relevant and cost optimized for North America’s many climate zones. Designs for Germany’s climate don’t exactly work in Chicago, Houston, or Las Vegas, etc. To improve building performance in hot, humid, cold, and mixed climates, PHIUS worked with Building Science Corporation under a grant from the U.S. Department of Energy to write the Climate Specific Passive Building Standard. This is an actual standard, available for jurisdictions to use as a model for building codes. PHIUS also worked with the Fraunhofer Institute of Building Physics to modify their WUFI hygrothermal modeling software into a design and verification tool for passive buildings tailored to North American climate zones and weather data.

We encourage you to read more about the PHIUS standard on their website, but don’t hesitate to get in touch with us to find a local professional or connect with our community. If you’re interested in getting started, you'll have to determine whether you want to opt for PHIUS’ modeled path, which allows you to optimize your assemblies with the WUFI Passive software or whether you want to simply comply with PHIUS’ prescriptive path. If you want to go the modeled route, you'll need to get in touch with a Phius Certified Consultant or CPHC and eventually a PHIUS Certified Rater and a PHIUS Certified Verifier for larger projects. If you want to go the prescriptive route, you can check out their requirements and enter your project's info into their snapshot tool to see how it shakes out.

In any case, happy learning and don’t be a stranger!