July 31, 2020


Yesterday saw the sixth, and final, day of the North American Passive House Network’s virtual conference, PH2020: Choose Your Future. As with previous days, the program ran from 1–4 ET and the sessions were divided up to include two pairs of 1‑hour presentations held simultaneously and a plenary panel, which in this case was led by Passive House Accelerator’s own Zack Semke, to close out the day.

Regulations Are Changing Everything: How Passive House Helps Mitigate Growing Risks

  • Ryan Cattley, CPHD – Senior Project Engineer, Jaros, Baum & Bolles
  • James K. Lin, P.E., LEED AP, CPHD – Associate Partner, Jaros, Baum & Bolles
  • Dylan Martello – Senior Building Systems Consultant, Steven Winter Associates

High-Performance Highrise Enclosures

  • Graham Finch, MASc, P.Eng – Principal & Senior Building Scientist Specialist, RDH Building Science

Buildings of Excellence: Case Studies in Elevated Expectations

Summer Comfort & Cooling: Designing Future Resilience

What Next? A Closing Plenary Discussion

  • Zack Semke, CPHC – VP of Marketing, Zola Windows; Director, Passive House Accelerator
  • Jessica Grove-Smith – Physicist, Passive House Institute
  • Andrew Lee, LFA, LEED AP, BD+C, Assoc. AIA – Director, Energy + Carbon International Living Future Institute
  • Bronwyn Barry, RA, CPHD – Principal, Passive House BB and NAPHN

Regulations Are Changing Everything

The first session of the day focused on New York City’s Local Law 97. The law uses more stick than carrot to encourage owners to be more energy conscious. They can accomplish this by either making their buildings more efficient or relying on carbon offsets (such as adding onsite renewable energy generators). Starting in 2024, the law will place clear limits on energy use in buildings over 25,000 square feet, and those who fail to comply will face significant fines.

Not all forms of energy use are equal, however, and each type of utility—natural gas, electricity, even steam—is assigned a different carbon coefficient based on the amount of carbon released into the atmosphere when the building takes from the utility grid. In 2030, these limits will become even more restrictive and owners could face very significant fines if they fail to comply.

Currently, electricity has the highest energy coefficient, but this will change as power production in New York becomes greener. As James Lin reminded listeners, the reason the grid’s carbon coefficient is so high is because the plants that feed into the system are still dirty. As the state is committed to converting the energy grid to 70% renewable by 2030, and 100% by 2040, the coefficient will diminish until it eventually zeros out once power generation throughout the state becomes 100% renewable.

This has the potential to confuse a lot of people, particularly owners. As a concrete example, consider the difference between a domestic hot water system that runs on natural gas and an electric domestic hot water system. Currently, the gas system has a smaller carbon coefficient than the electric one. In 10 years, however, New York’s grid will be far less dirty. Consequently, the electric system will have a small carbon coefficient.

As Dylan Martello and Ryan Cattley explained during the session, this not only may cause confusion; it may also lead owners to feel as though they have a false choice of either being burdened by some fines now to avoid compliance issues in the future or complying now and facing fines in the future. There is a far more sensible option, of course: Upgrade to Passive House.

As more owners are realizing, Passive House may be a significant capital expense, but it significantly reduces operating expenses, it increases tenant comfort, and it is a healthier alternative to code-built homes by providing hygiene ventilation. These three factors have made it far more popular, especially as more people throughout the world become cognizant of the importance of constructing healthy buildings.

As Passive House emerges from its position as a niche building standard and elements of the Passive House principle begin to be incorporated into building and energy codes across the country, more developers will realize that it not only the most efficient and sustainable model, but the most financially sound one, as well. Lin also noted that legislative trends will likely continue to move the industry in the direction of Passive House, particularly in the Northeast, and that this will further drive innovation.

“It’s an exciting time for high-performance buildings,” Cattley said.

Summer Comfort & Cooling

Similar to the issue of fluctuating carbon coefficients is the issue of designing to the Passive House standard in a changing climate. As Jessica Grove-Smith explored in her one-woman session, one of the primary objectives of the Passive House standard is to keep occupants comfortable in terms of relative humidity levels and air temperature. Optimally, relative humidity should remain within the range of 30 percent to 60 percent, and indoor air temperatures should not exceed 77° F more than a few days each year.

To ensure buildings stay within these ranges, designers rely on climate models that provide rough approximations of weather conditions around the project site. These models not only inform building orientation; they also influence design choices. In the context of preventing overheating, they let designers know if the building can be outfitted solely with passive features that can be easily controlled by occupants (like shading components or ventilation systems that rely on nighttime flushing of hot air) or if the designer has to install an active cooling systems.

If these models are no longer reliable due to climate change, then this presents some serious problems for designers. What should they do?

As Grove-Smith advised, controlling solar gains and designing mechanisms that allow for night ventilation are one way to mitigate this issue, but it may not be enough. Teams should be running stress tests during the energy modeling phase of design to see how the building responds to extreme and protracted heatwaves. If designers find that there could be a high risk of overheating frequency (interior temperatures exceeding 77° F on more than 10% of days), then it is probably best for the long-term performance of the building to incorporate active cooling features rather than to hope for the best and be forced to install these systems in the future.

What Next?

The conference’s final plenary session began with a presentation by Zack Semke. Semke opened by retelling the parable of the 1,001 days in the life of a Thanksgiving turkey, as made famous by Nassim Taleb in his 2007 book, The Black Swan. In the story, the first 1,000 days of a turkey’s life are consistently pleasant. The humans give them food, water, and shelter. If a turkey gets sick, they are given medicine. If a turkey is injured, they receive care.

For the turkey, such generosity is proof of humans’ benevolence. For 1,000 days, this belief is only reinforced.

Day 1,001, however, is very different. This is because day 1,001 is Thanksgiving (or perhaps slightly before for those who buy their turkeys at the store), and that means the human’s relationship to the turkey goes from that of caregiver to that of slaughterer.

This kind of experience is known as a black swan event. It is unforeseen and it upsets all models created prior to the event.

Throughout the world, there appears to be several concurrent black swans. Some, most reading this would agree, are negative: the election of increasingly authoritarian and incompetent leaders in formerly liberal democratic states; climate change; the coronavirus pandemic. Others, most reading this would agree, are positive: the massive protests following the murder of George Floyd and the reinvigoration of the Black Lives Matter movement; the surge in awareness about climate change due to the work of individuals like Gretta Thunberg. As Semke noted, the lesson that emerges here is that black swan events may seem disastrous at first, but that they can also inspire mass movements to emerge from seemingly out of nowhere.

He then asked, What do we have to do enact this kind of change?

This was not just a rhetorical question. Following Semke’s address, it was asked to each member on the conference’s final panel: NAPHN President Bronwyn Barry, Passive House Institute physicist Jessica Grove-Smith, and Andrew Lee of the International Living Future Institute. For Barry, the answer is to be nimble. For Grove-Smith, it is to be louder. For Lee, it is to listen more.

To listen to not only the rest of this panel, but the roughly 30 hours of sessions that took place over six days, you can still register to have access to the conference archives. If you’ve already registered, but haven’t had the opportunity to listen to this discussion yet, it is highly advised that you do.


Jay Fox
Jay Fox
Jay Fox is a writer and musician based in Brooklyn. His work has appeared in Crain's New York, Salon, Stay Thirsty Magazine, Aethlon, and…

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    Our coverage of PH2020 was made possible in part by generous support from Zola Windows.

    Our coverage of PH2020 was made possible in part by generous support from Zola Windows.

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