Is This Building Passivhaus-Certified?
American and German certifying organizations disagree over whether this Canadian duplex, the Rideau Residences, meets the Passivhaus standard
UPDATED February 7, 2012 with a response from Wolfgang Feist
The first residential Passivhaus building in Canada is the Rideau Residences, a duplex at 279 Crichton Street in Ottawa. The building has impressive specifications: an R-70 foundation, R-50 walls, an R-70 roof, and triple-glazed low-eLow-emissivity coating. Very thin metallic coating on glass or plastic window glazing that permits most of the sun’s short-wave (light) radiation to enter, while blocking up to 90% of the long-wave (heat) radiation. Low-e coatings boost a window’s R-value and reduce its U-factor. windows. The building’s air leakage rate was tested at 0.58 ach50.
On November 22, 2010, the Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. Institute U.S., an organization with headquarters in Urbana, Illinois, issued a document to the developer, Christopher Straka of Vert Design, certifying that the Rideau Residences met the Passivhaus standard.
Up until that point, the certification process had gone smoothly. But then the Rideau Residences story took a strange twist.
The certificate is challenged
One of the consultants involved at the early stages of the Rideau Residences project was Malcolm Isaacs, a civil engineer and founder of the Canadian Passive House Institute. Isaacs was eventually replaced by Ross Elliott, an energy consultant and the owner of Homesol Building Solutions. According to Isaacs, “I was the Passivhaus consultant on that project initially, but I was not involved in the construction of the house.”
Isaacs had partial knowledge of the project’s details — enough information, he felt, to bring a complaint to the Passivhaus Institut in Darmstadt, Germany. The essence of Isaacs’s complaint was that several as-built features of the Rideau Residences differed from the project documentation. In Isaacs’s view, these differences were serious enough to question the legitimacy of the building’s Passivhaus certification.
In a July 2011 e-mail to André Fauteux, the editor of a Canadian construction magazine called La Maison du 21e siècle, Isaacs wrote, “I repeated several times to Louise [Legault] that almost certainly this house does not come near the international PH Standard, and that this view is endorsed by the Passivhaus Institut in Germany, who are currently auditing it. … You can be sure that the Passivhaus Institut is treating this matter extremely seriously.”
Feist appears to endorse Isaac’s view
How seriously did Dr. Wolfgang Feist, the director of the Passivhaus Institut (PHI), take Isaacs's concerns? Very seriously, as it turns out — seriously enough to publicly accuse the Passive House Institute U.S. (PHIUS) of certifying buildings “without the requisite documentation.” Feist concluded that the certificate issued to the Rideau Residences was so unjustified that it was time to cancel all contracts between PHI and PHIUS.
In short, the certificate issued to the Rideau Residences was one of the causes of last August’s PHI-PHIUS divorce.
In his August 17, 2011 letter announcing the divorce, Feist wrote, “Evidence of PHIUS’s certification of Passive House buildings without the requisite documentation has threatened the integrity of the standard and forced PHI to terminate PHIUS’s status as an accredited Passive House Building Certifier.”
On October 5, 2011, Ross Elliott gave a presentation on the Rideau Residences at the GreenBuild conference in Toronto. He explained that the complaint filed with the Passivhaus Institut alleged that there were several possible problems with the project:
- A thermal bridge at the brick ledge wasn’t properly accounted for.
- The solar heat gainIncrease in the amount of heat in a space, including heat transferred from outside (in the form of solar radiation) and heat generated within by people, lights, mechanical systems, and other sources. See heat loss. calculations failed to account for a pine tree that partially shades some of the building’s lower windows during the winter.
- The project’s HRVs and windows hadn’t been certified by the Passivhaus Institut in Germany, rendering their specifications suspect.
For North American Passivhaus designers, this last issue has been a bone of contention for some time. According to Mike Eliason, a designer at Brute Force Collaborative in Seattle, Washington, “Utilization of certified Passivhaus components ensures the values entered into PHPP are verified and accurate. This can be crucial and have significant implications when it comes to HRV/ERV(ERV). The part of a balanced ventilation system that captures water vapor and heat from one airstream to condition another. In cold climates, water vapor captured from the outgoing airstream by ERVs can humidify incoming air. In hot-humid climates, ERVs can help maintain (but not reduce) the interior relative humidity as outside air is conditioned by the ERV. efficiency. If the product is not certified, 12% must be deducted from the heat recovery efficiency. For a (currently) uncertified product like the UltimateAir Recouperator, which claims 95% efficiency, we can only utilize 83% in PHPP.”
Katrin Klingenberg defends the certification
After Dr. Feist accused PHIUS of issuing an undeserved certification, Katrin Klinenberg, the director of PHUIS, defended the process used to certify the Rideau Residences.
In an August 19, 2011 letter to Feist, Klingenberg wrote, “We were asked [by PHI] to provide all the drawings and documentation for the certification and we were told after an unusually quick review of what we submitted, that the PHI had concluded that this project is not anywhere close to the standard. … The [heat-recovery] ventilator data turned out by PHI’s own rules to be just fine, just as we had it entered in the PHPP.”
Klingenberg continued, “Now 8 months after we initially certified the project, the window company finally agreed upon our insistence and inquiries to provide the actual THERM files for the window brand, which they previously had refused. The window values were slightly worse than we had initially assumed. … PHI has never provided us with the accurate calculation method for window frames even upon inquiry (I am assuming it is to protect their product certification as proprietary) so we were left like everybody else to make an educated guess as best as we could based on the information that was available to us last year.”
Concerning the brick ledger, Klingenberg wrote, “We had been told that the angle holding the brick veneer would be thermally broken with aerogel. That had not been documented in the drawings but communicated verbally. This was not implemented on site. … This pointed to the need for more standardized on-site quality assurance and third-party field verification, which we have actively created with the PHIUS+ program.”
Klingenberg noted that it is difficult for a certifying agency to verify all of the specifications submitted by an architect. “The certification protocol currently does not require proof of exact shading calculations. … The experience here shows that higher insolationAmalgamation of the words “incoming solar radiation” that means the total amount of solar energy that strikes a given surface in a given time. It is commonly expressed in kilowatt-hours per square meter per day. in North America needs a more strict quality assurance requirement and we would like to suggest adding to the blower door test and commissioningProcess of testing a home after a construction or renovation project to ensure that all of the home's systems are operating correctly and at maximum efficiency. protocol the requirement for a solar pathfinder study, to avoid these kinds of problems.”
In a January 5, 2012 e-mail to André Fauteux, Klingenberg summed up the situation: “Documentation was all there. Except the altered detail which was communicated verbally and not confirmed on site as there is no provision for that type of Quality Assurance from the certifier. We have to rely on the architect, builder, etc. And aside from that, this detail was really minor in terms of lessening the performance. At that point we are really talking peanuts. They are prejudiced and think that there can't be a good North American ventilator (they want to sell the expensive European stuff!), so they assumed we were using the wrong values because they were meeting their specs. Turns out, indeed, Lifebreath is meeting it. So, their beef was wrong. Last and most important issue, that did kick the project out of the certification range, is entirely on them. There is no site verification if the shading assumed in the PHPP is actually correct (solar pathfinder etc not required). In this case, if it had been required, we would have caught the mistake in the theoretical shading assumptions.”
Duking it out in public
This public dispute raises several questions, including these:
- Is the skepticism concerning the performance of Canadian materials that aren’t certified by the Passivhaus Institut reasonable or biased?
- Could any Passivhaus building in any country stand up to similar under-the-microscope scrutiny by someone looking for minor flaws or discrepancies?
Once the dispute between PHI and PHIUS became public, Elliott quickly realized that the building under discussion was the Rideau Residences. Referring to the buildings mentioned in the public letters, Elliott wrote, “Might that be the PHIUS-certified Canadian house Malcolm Issacs has declared definitively and publicly on several occasions (including recently to very influential Canadian green building media trying to promote PH) was ‘nowhere near Passive House’? The one he flew to Germany to complain about and re-open eight months after Katrin passed it in November 2010? … Is it about solid, impersonal spreadsheet numbers adding up correctly, or about personality clashes and intransigent opinions on how someone should build and what products they should be allowed to use? Are we learning from or competing against each other?”
When I spoke to him recently, Malcolm Isaacs told me, “We did ask PHI some questions. I was the person who raised these questions, because the building was aiming to be the first passive house in Canada, and we needed to be sure that it was. I have been in contact with PHI on this, and they have not said anything yet.”
Isaacs also said, “I have managed to ruffle a few feathers.”
The building is still certified
Editor André Fauteux wrote, “We contacted Wolfgang Fiest, the founder of PHI and the author of the [August 17] letter, and asked him whether or not the Ottawa duplex satisfied the requirements of his organization, and if the certification that had been issued to it would be rescinded. Dr. Feist has still not answered our questions.” [Update: On Februrary 7, 2012, Feist responded to questions about the Passivhaus certificate awarded to the Rideau Residences; his response has been included at the end of this article.]
Since PHI has publicly disassociated itself from PHIUS, Dr. Feist has apparently washed his hands of any involvement with PHIUS’s certification decisions. Since PHIUS's certification procedures were found wanting by PHI, none of PHIUS’s certifications meet international standards anymore. As a result, the certification issued to the Rideau Residences — a type of certification that is recognized only in the U.S. — still stands.
The developer of the Rideau Residences is Christopher Straka of Vert Design, a design/build firm in Ottawa. As far as Straka is concerned, his building is Passivhaus-certified. Straka told me, “I have never received a phone call or letter indicating that the Passive House certification for the building has ever been challenged.”
When discussing the way his building was challenged, Straka takes the high road. “The Rideau Residences were a great learning experience,” he said. “Overall, a bit of controversy behind the curtain doesn’t hurt anyone as long as the questions are positive, with the mission of getting better building methods.”
Local versus imported materials
One of the questions raised by l'affaire Rideau is this one: Is it better to use local materials, or materials that have the stamp of approval of the Passivhaus Institut in Germany? Isaacs and Straka have different answers.
“We cannot use Canadian HRVs in Passive Houses, simply because they perform so poorly — a sad truth,” Isaacs wrote. “I installed a highly rated VanEE [heat-recovery ventilator] unit in my own house (‘80% efficiency’). I have measured the supply air temperature coming into the house when the exterior is at -10°C, and it is around 5° - 7°C. For the Paul [HRV] unit we used in Montebello [a different Passivhaus project in Canada], the supply air is guaranteed to be at 17°C. This makes a huge difference to annual energy use!”
Taking an opposing position, Straka says, “I do believe that Canadian-made construction materials and systems can be combined to create Passive House buildings. … I believe that limiting the selection of components a project team can use (to those recommended by the Passivhaus Institut) will stifle innovation and limit the adoption of the Passive House standard in Canada.”
Straka told me, “I believe that we can build better buildings by building local buildings, with materials sourced from your region or country. That is better than reaching overseas. That’s not to say there aren’t great products produced overseas. But we should strive to be getting our materials by driving across town instead of getting materials from 6 time zones away.”
One more twist
When researching this dispute, André Fauteux sent an e-mail to Katrin Klingenberg, asking several questions about the Rideau controversy. In her e-mailed answer to Fauteux, Klingenberg commented on an unrelated technical matter: “Yet Dr. Feist and his followers still claim that 15 [kwh per square meter] is valid equally in any climate and anywhere in the world. It is almost impossible in very cold climates as far as I can tell. I have not been able in all those last 12 years that I have been working with the German PHI to receive a good physics-based answer for this claim. Have come to the conclusion that there is none. The best explanation I can find is that 15 is the arbitrary result after applying the low load physics relationship between ventilation air and peak load in the central European climate.”
Until last year’s PHI-PHIUS divorce, Klingenberg publicly defended the logic behind the standard’s annual heating energy limit, so her recent challenge to the requirement is surprising, to say the least.
When Fauteux forwarded Klingenberg’s e-mail to me, he pointed out that her words are eerily similar to ones I wrote in my April 1, 2011 blog on this topic: “The next problem with the Passivhaus standard is that the annual space heating limit of 15 kWh/m²∙year is arbitrary. The requirement is easy to achieve in a mild climate, but tough to achieve in a cold climate. Where did this limit come from? It appears to simply represent the space heating energy required to heat a well-built superinsulated home in the climate of Central Europe, with the following assumptions:
- Space heat must be delivered through ventilation ducts.
- Ventilation rate = 0.3 to 0.4 air changes per hour.
- Temperature of ducted air = no higher than 122°F.
- The best windows in Europe are U-0.14 windows; the best achievable air tightness is 0.6 ach50.
With these limits specified, the best houses in a central European climate need 15 kWh per square meter per year for heating.”
Needless to say, I agree with Klingenberg on this issue. The Passivhaus standard's heating energy limit of 15 kWh/m²∙year is arbitrary.
Dr. Wolfgang Feist responds
On Feburary 7, 2012, Dr. Wolfgang Feist, the director of the Passivhaus Institut in Darmstadt, Germany, responded to questions about the Passivhaus certificate issued to the Rideau Residences.
Feist wrote, “The Passive House Institute has developed the Passive House Planning Package (PHPP) design tool to facilitate the design process and has instituted a rigorous (voluntary) certification process. ... The certifiers are entrusted with upholding the standard and ensuring the quality of the buildings they certify. They thus carry a great responsibility in their work and must diligently document the building as well as the quality of the components used. Should it become clear that an accredited Building Certifier is not up to this task, it is the Passive House Institute’s duty to revoke this Certifier’s rights to certify in the Institute’s name so as not to undermine either the Institute’s principles or the Passive House Standard itself.
“PHIUS’ assessment of the Ottawa house, unfortunately, was just such a case. In fact, much of the essential documentation necessary to determine energy balances — the foundation for the entire certification process — was not available when requested by PHI. Even on the basis of the partial data provided to PHI, it was clear that any properly conducted energy balance would result in an energy performance far removed from the Passive House Standard. PHIUS’ latest statements have shown that the organization is not even trying to claim that either the 15 kWh/m²a heating demand criterion or the 10 W/m² heating loadRate at which heat must be added to a space to maintain a desired temperature. See cooling load. criteria have been met. On the contrary, they claim that these criteria do not make sense. There is no question that an organisation taking this position did not take and, indeed, could not have taken its responsibilities as an accredited Building Certifier seriously and was acting to the detriment of the Standard. It is simply irresponsible to misguide the public by claiming that such changed criteria lead to the same proven results as the well-recognized Passive House Standard does. Those choosing to use different criteria should at least be so honest as to not use the term ‘Passive House.’ ”
Last week’s blog: “Service Cavities for Wiring and Plumbing.”
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