I’ve been on the road a lot lately but let me thank you again for your thoughtful contributions and the
healthy debate sparked by my first blog post, “15kwh is Dead, Long Live 15kwh.” In the post I put forth PHIUS’ plans to modify the passive house standard to address the specific climate and market needs of the North American market. A quick summary of the changes and their value:
- Modifications will be based on the first and only large-scale analysis of passive house buildings in the United States and Canada – the 100+ buildings certified/under review by PHIUS.
- They will address the substantive and reasonable critiques (such as the small-home penalty) of leading building scientists in North America like John Straube, Marc Rosenbaum, and Martin Holladay.
- They will safeguard the high quality for which passive house is known by acknowledging
fundamental differences (e.g., building in high-humidity zones presents unique quality challenges).
- Modifications will calibrate envelope improvements more precisely for each climate and will be more cost effective than the one-size-fits-all approach. They will improve cost effectiveness in colder climates while maintaining comfort and quality of the envelope. And they will actually tighten the standard in climates where there is opportunity for more stringent targets.
The post touched off a great deal of constructive discussion and supportive comments – many folks expressing support for an idea they believe was long overdue.
Understandably, the prospect of change also caused some angst. Recently, a petition was circulated asking folks to sign-on in support of maintaining a single numerical standard associated with the term passive house. I fully understand the response – years ago, I might have signed on myself. But since then, based on the collective experience of passive house consultants who have designed and constructed projects across the continent, it’s become clear that adaptation is critical.
It’s also become clear that we at PHIUS need to get better at explaining the rationale for the modifications that we’re proposing and how they will help propel the market forward while maintaining the core principles of passive house.
To that end, I’d like to respond to some of the concerns and ensuing discussion around the petition mentioned earlier.
Let’s start with a sentiment expressed in a Green Building Advisor article related to the petition topic: It was expressed that the “beauty of the standard is its purity.” Purity implies uniformity, and my intended point is that 15kwh is not a universal truth, and therefore not practical for all climate regions. The rigor of passive house is universal. In the US, 15kwh is rigorous and practical in the Pacific Northwest but hat’s not the case in most of the other North American climate zones.
By the same token, in some areas of the United States – Southern California, for example – it’s technically and economically practical to do better than 15kwh. And it’s worth reiterating: adjusting the standard will allow us to do away with the small-house penalty (that being that it’s actually easier to achieve 15kwh in a larger structure than a small one, thereby presenting an incentive to build larger).
As mentioned in the first blog post, other parts of the world have already concluded that 15kwh is not universal. This is really not a new development.
More important, is the suggestion that modifying the standard creates market confusion. Three points argue against this being a concern:
1. Passive house is not a brand. Passive house is a generic term for structures that require little or no actively generated energy for heating and cooling. Put another way: “Passive house” is the equivalent to “hybrid automobile.” Car manufacturers now make their versions with their brands.
2. Passive house applies to the principles and practices – which are universal – required to build passive structures. Many of them — superinsulation, airtightness, energy recovery ventilation, managing solar gain — originated in the United States and Canada. They don’t belong to anyone. They are not brands. And they are available to all designers and builders who want to learn to apply them. They remain intact and powerful regardless of any number.
3. As more competitors arrive in a growing market wishing to offer passive house products clear branding of different passive house products (different trainings, quality assurance protocols or standard variations) is important to avoid confusion in the market place. PHIUS has differentiated its product by creating the PHIUS+ program.
Market size is a bigger concern. Passive house has come a long, long way in the past several years. But the market is still tiny. The imperative is to grow the market. And it will not grow if we adhere to a standard that isn’t practical in large swaths of the continent.
By making the standard applicable across the continent, and teaching professionals how to make passive house work where they work, we can help passive house principles go mainstream here in North America. We can make passive house principle best practice. And that will achieve all of our ultimate goals: Less energy, less pollution, more comfort. All thanks to passive house.