Insight
A Conversation About Passive House with Kate Theodoridis and Matthew Cox
Passive House is a building standard focused on energy efficiency, comfort, and affordability, achieving around 90% energy savings on heating and cooling through superior insulation and airtight construction, according to Passive House Institute. It maintains a stable indoor temperature and high air quality, reducing the need for conventional heating and cooling systems. The certification requires architects to meet rigorous standards for energy efficiency, thermal comfort, and airtightness, involving high-performance insulation, windows, and ventilation systems. This certification demonstrates architects' commitment to sustainable design and enhances their expertise in creating low-energy, environmentally friendly buildings.
What prompted you to get your Passive House certification?
Matthew Cox, AIA, NCARB, LEED AP BD+C, CPHC: Having completed a couple of LEED certified projects in the past, that led me to explore some of the other sustainability-focused certifications such as PHIUS & PHI, Living Building Challenge, etc. Ultimately, I settled on PHIUS’s passive house course and certification.
Kate Theodoridis, AIA, LEED Green Associate, CPHC: I learned about Passive House as a concept pretty early-on in my career, but I never knew it was a certification someone could obtain until 2018 when my project manager at the time got hers. Since then, it was always on my radar as a certification that aligned with personal values of how we should design buildings. The preliminary roll-out of the new energy code was ultimately what made me decide that it was time to finally dive in.
How does it help you with your current projects?
Matthew: Designing for passive house requires a much higher attention to detail. This rigorous approach to documenting and developing a project permeates through every project I work on.
Kate: Passive House training was really great in helping me understand the differences between different heating and cooling options for buildings. I believe I am a more well-rounded architect because of it, and Ican have more informed conversations with clients and consultants moving forward.
Has it impacted or changed your design process?
Matthew: Definitely! At all stages of design there are impacts that Passive House designs can bring: maximizing (or minimizing) solar heat gain through orientation of a building, highly insulated wall and floor assemblies to keep the building at a comfortable temperature, energy modeling to optimize the mechanical systems, and testing during construction to ensure the standards of design are being met.
Kate: Absolutely. Gone are the days of using curtain walls and glass everywhere. We are having to get creative with ways to daylight our spaces and maximize views. Some may look at it as a limitation, but I think it’s just another design problem that needs to be solved – and that’s what we’re good at!
Why is the Passive House certification valuable to firms?
Matthew: Firms should value Passive House certifications because it shows that their employees have a high level of knowledge about building science and design. It can also unlock the segment of the market where knowledgeable clients know that they want sustainable and energy efficient design from the get-go.
Kate: Agreed, I think a number of people get their CPHC not only because of the added expertise, but because they are truly interested inbuilding science. CPHC certification shows clients that we have an added level of knowledge but also excitement about sustainable design.
What differentiates this certification from others like LEED or Living Future?
Matthew: Other certification programs such as LEED and Living Future tend to take a holistic approach and look at all aspects of design. They may track material’s carbon footprint or access to public transportation or amount of plantings and greenery. Passive House may acknowledge that those other areas contribute to the sustainability of a project, but it focuses on maximizing energy efficiency.
Kate: Ever since ‘sustainability’ has become a buzz word, there has been an immense pressure on architects to specify the ‘greenest’ materials possible, or to draw our details perfectly so we can achieve the targeted EUI. While that pressure still exists no matter what kind of sustainable certification you are targeting, Passive House shines a huge spotlight on the trades in the field who are doing the work with a massive quality control component which other certifications lack. If it’s not built right, it won’t pass a blower door test, a method to measure the air tightness of a building, which means no certification, and that’s not acceptable.
What typically deters designers or clients from pursuing Passive House Certification? How do you think those challenges can be met?
Matthew: I think there is a stigma to the cost associated with “green” building design that the industry is still trying to move past. In my opinion this comes from a general unfamiliarity with what building sustainably entails. When integrated from the start Passive House projects can expect to see a 1-8%increase in capital costs (dependent on experience of the design and build teams) and can achieve up to a 63% reduction in energy usage, according to Passive House Network White Paper. This reduction in energy usage can lead to a relatively short payback period for the upfront cost increase. I think providing more education to the public and the industry is a positive thing for passive house builders, designers, and certifiers.
Kate: Agree with Matt. In addition, Passive House projects may have slightly longer schedules than a typical project because of blower door testing requirements. It’s typical that extra time is added in order to correct errors in the construction phase. I think setting expectations is key here in managing this challenge. The good thing is that once more and more contractors and builders become familiar with Passive House standards, errors will be minimized over time, and this may not be an issue in the future.
Passive House standards are typically applied to residential buildings. Can you explain how the standards benefit large-scale projects?
Matthew: Yes, it’s true that Passive House was started and originally aimed at promoting energy efficiency in single family residential homes. However, the scientific principles being applied to reduce energy use (airtight envelopes, thermal bridge free design, thicker insultation) may be used in any project type. PHIUS has since launched their own parallel requirements for commercial buildings as well as a different track for multi-family buildings.
Kate: The bigger the building, the higher the energy use. Passive House reduces energy use which keeps dollars in our clients’ pockets. The scale of that impact increases with the scale of the building.
Why should clients be interested in Passive House standards? What kind of benefits do they get out of certification as the building owner, operator, or user?
Matthew: A decrease in energy usage means utility smaller bills for owners and tenants! Smaller mechanical systems are often more resilient and require less specialized maintenance. An airtight building means less moisture intrusion and less repairs needed. Thermal-bridge free design means no more drafty spots on the exterior and more comfortable and happy tenants.
For clients who are interested in building a Passive House Certified project, where should they start?
Matthew: Call us! Our Passive House Certified (PHI + PHIUS) architects can walk you through how to apply PH principles to your project or even give you an overview of the certification process.
There are also many free resources online that can explain the principles and science of passive house design:
Likewise there are many books available, including:
- Passive House Details by Corner, Fillinger, and Kwok
Kate: Please reach out! We are available and excited to provide our guidance and expertise every step of the way.
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