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Musings of an Energy Nerd

Is This Building Passivhaus-Certified?

American and German certifying organizations disagree over whether this Canadian duplex, the Rideau Residences, meets the Passivhaus standard

The validity of the Passivhaus certification awarded to the Rideau Residences, a duplex in Ottawa, has been challenged.

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-e windows. The building’s air leakage rate was tested at 0.58 ach50.

On November 22, 2010, the Passive House 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…

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  1. user-1089563 | | #1

    Canadian passive houses

    This is a good report. I know many of the people involved and you treated them fairly. It would be interesting to know the status of the Montebello house mentioned: it seems to be waiting for certification according to reports in the Quebec press recently.

    It is too bad that reputable builders who have created an energy-efficient house are getting entangled in technicalities. I suppose that this is the downside of certification procedures.

  2. gusfhb | | #2

    Kind of sad when people working for the 'good' cannot get along

    The proof is in the pudding as they say, one wonders after all the fuss an bluster, whether the building performs as a Passivehaus

  3. GBA Editor
    Martin Holladay | | #3

    Response to Don Fugler
    Thanks for your positive review of this report.

    Anyone interested in more information on the Montebello passive house might want to read the September 2010 GBA news story that mentioned the house, Passive House Finds Friends in Canada.

    Further information (in English and French) can be found here: Backgrounder: Passive House.

    The images attached below came from

  4. dankolbert | | #4

    The road to hell
    etc. Although I guess the quality of the intentions is up for debate. Long Live the Pretty Good House!

  5. GBA Editor
    Martin Holladay | | #5

    About Dan's "pretty good house" comment
    Dan Kolbert and Michael Maines have been working on an article on the "Pretty Good House" -- a Maine proposal for a standard that differs in several ways (mostly by depending on something called common sense) from the Passivhaus standard.

    Stay tuned -- GBA will be publishing Michael's article on the Pretty Good House very soon.

  6. user-757117 | | #6

    I'm looking forward to reading about the "Pretty good house".
    I think I grasp the idea - I consider my own house that I'm building to be a "pretty good house".

    I've often wondered why people sometimes get so hung up on arbitrary certification standards...
    As though there needs to be a "brass ring" for people to be interested in building high quality enclosures...

  7. DrDanger | | #7

    "Pretty Good House"
    I too am looking forward to this article. I do like the overarching goal that PassivHaus represents, and that certification could be desirable. Why? It represents much better and energy efficient housing than code or what most LEED projects achieve. Some day I hope that their could be many of such homes on this side of the pond and people will be buying them. These folks won't necessarily know all that goes into creating a PassiveHaus, just like I don't know all that is going on inside my computer, however these people know that they are buying ahighly energy efficient structure. Better yet would be if houses (at least new construction for a start) were to be required to have a sticker on them like any of our appliances do showing how much energy that house will use, however I remain a pessimistist that I will live long enough to see this be come required. I used the PHPP software to help design and build my house. It taught me much, however it certainly has some limitations in its use in North America, chiefly its required window data requrements that are not available (frame factors mostly).
    I have read that to become Passive House certified all you need to do is acheive 0.6 ACH@50Pascals, and its 15 kwh per M2, which is not have to use their software. I certainly think their software can be reasonable accurate estimation, but why not allow (or better yet require) for objective measurement. The results could be used to refine the program over time.

  8. user-869687 | | #8

    Response to Kevin O'Meara
    You have a good point--if PH status could be based on actual energy use--something easily measured--then it wouldn't matter so much whether the brick ledger is accurately modeled. Results would be all that matter. A building could even have annual updates of its energy efficiency status, reflecting any modifications (e.g. adding a pool) and occupant behavior. Or, someone could build a "pretty good house" and later conclude that it meets PH efficiency, which may have less bragging rights but still make the owners happy.


    Compare the cost or certification to the cost of monitoring
    For about $2,000 I can get an eMonitor installed and watch the energy usage of my buildings as they are occupied and get immediate graphs representing system interaction with weather and client usage. I can see clearly how my reasonably well-built (HafassivHaus) homes are performing. The Bryant Residence ran through 57 KWh/sqM/yr during it's first twelve months and we have another that we have just finished a years worth of data collection and another where we are just getting started.

    Monitoring looks like a very cost effective way to make continual improvements in your building systems compared to modelling. I'm not saying to throw out modelling but only that modelling without monitoring is only half the process and that a building that can be shown to use 15 KWh/sqM/yr should be viewed as equal to Passivhaus regardless of the pine tree not accounted in the modeling. I think that Ted Clifton's projects are more than meeting this mark.

    Mine still have a ways to go but getting closer all the time thanks to all the great stuff I've learned from the community here and at the EVHA awards and NAHB Builder 20 and CGP-MCGP community.

  10. albertrooks | | #10

    Monitoring is "da bomb"!
    I look forward to the day when monitoring is accessible and dare I say... Common.

    Modeling with the PHPP, or with anything else, steers the project to a good design. Site QA keeps the execution on track.

    Monitoring provides what I think are the two significant benefits as stated above:

    1: Check the model and see if it works.

    2: It provides a continual feedback loop to the occupants. In the end, once these are modeled to very low, or no energy, it's down to the occupants and their use of DHW and plug loads.

    What was the blog? "No net zero homes, just net zero families".

    Passive House, Pretty Good House, LBC -All of these are great programs. As long as they don't get in their own way.

    In the end, it's all about the buildings. Not the programs.

  11. GBA Editor
    Martin Holladay | | #11

    Monitoring to see if a house meets Passivhaus?
    I'm all in favor of monitoring -- what we don't measure, we can't improve -- but the engineers and physicists who dreamed up Passivhaus have a false sense of precision. This amount of precision is unachievable.

    In the real world, occupied Passivhaus buildings don't all use the amount of energy predicted by the model. If there are three Passivhaus homes, all identical, all modeled to use X amount of energy per year, one family will use X, one will used 2X, and one will use X/2.

    The only way you can use monitoring to determine that a particular model of Passivhaus meets the standard is to build 1,000 of them, occupy them with 1,000 families, and divide the energy use of the 1,000 families by 1,000. And even then you have to normalize the data for weather!

    Chasing rainbows...

  12. homedesign | | #12

    Dewey, Cheatum & Howe
    Michael Chandler (AKA ShelterNerd),
    You are NOT authorized to use the term HafassivHaus
    It is too similar to my trademarked terms "Half Passive House" and "Half Assive House"
    I believe that Albert Rooks coined the terms "HalfassivHaus" and "HAHPP"
    we will be contacting our attorneys

    You MUST Cease and Desist...

  13. GBA Editor
    Martin Holladay | | #13

    John, your language is not strong enough
    You're not supposed to say, "you must." The correct legal phrase is, "we demand."

  14. Paul Eldrenkamp | | #14

    chasing rainbows?

    I don't think you're making a clear enough distinction between two evaluation methods in your post "Monitoring to see if a house meets Passivhaus?"

    Evaluating a building by means of a PHPP model is a way of gauging the quality of the building as a a tool. I think this is a useful thing to try to do with some precision. Looking at actual energy usage of that building, on the other hand, is a way of gauging how well that tool is used. Two very different things, obviously. A really good building (that meets the PH standard, for instance) may have relatively bad actual-usage numbers because the occupants don't know how to use the building, or don't really care. A mediocre building can have really good numbers because the occupants are really aware and careful. This is not news to anyone who reads these discussions.

    There's an ongoing debate about when to stop adding insulation and to start adding renewables. It seems like there could/should be a similar debate about when to stop spending money on the building envelope OR renewables and start investing in occupant training and feedback devices, as several people have suggested in this thread. I'm pretty sure some of my remodeling clients are achieving really good usage numbers just because they know we're looking at their utility bills with them periodically, and thinking about what the numbers mean -- that basic level of paying attention often saves more energy than adding yet another 1" of foam to the outside, and it's a lot cheaper.

    --Paul Eldrenkamp

  15. GBA Editor
    Martin Holladay | | #15

    Response to Paul Eldrenkamp
    I understand that modeling and monitoring have different purposes. I was responding to T.J. Elder's suggestion that maybe "someone could build a 'pretty good house' and later conclude that it meets PH efficiency." To me, that sounded like an attempt to use monitoring to verify whether or not a house met the Passivhaus standard.

    Let's say that there is a building -- perhaps the Rideau Residences -- that is the object of a dispute between two Passivhaus organizations. One group says that it meets the Passivhaus standard, and the other group says that it falls short. Do you think that you could resolve the dispute with monitoring alone?

    I don't think so, because there are too many variables. The weather normalization alone is a nightmare -- it involves both heating degree days and insolation, as well as several other possible factors. Moreover, one also needs to monitor the thermostat setpoint, which may change daily. Appliances affect internal heat loads, so if the occupants buy a plasma TV halfway through the winter, the heat load that needs to be satisfied by the space heating equipment will be reduced. There are several other factors that could affect the monitoring data, including how the occupants operate their mechanical ventilation equipment.

    With enough monitoring equipment and enough weather data, this may be achievable -- but I think that anyone who proposes using this method to determine whether a questionable house meets the Passivhaus standard will find the method daunting.

  16. albertrooks | | #16

    Upward spiraling costs
    I am also sensitive to the "Geewiz... We can do that now!? Lets add it in!!" issue.

    Regardless of all the crazy material and system suppliers that keep foisting complexity and cost onto these buildings (me included)... The central message and effort for the Passive House Community is the continual focus on CEPH: Cost Efficient Passive House.

    Sure there are big budget projects. What can you say? "A girls gotta eat" as the saying goes. However most of the people I interact with are continually working towards very high performance building for mainstream Americans.

    That's the "Golden Target". Passive Houses for the masses. The whole point in the "endeavor" is environmental stewardship after all. The "masses" are where the volume and the need is.

    I'm happy to share that we are hearing from a growing number of Habitat for Humanity chapters for PHPP's, air sealing questions and the like. Regardless of the fractures, Cost Efficient Passive House is growing at a really good rate in the US.

    Add other programs growing at a good rate, and it's really good news for future mainstream Americans' ability to live in a "Low Energy & Resilient Home"

    My point on monitoring occupant usage is not to say that we need to add more gadgets. The day I was looking forward to is the day when good monitoring of category usage (DHW, Heating/cooling, plug loads) are delivered by the utility. it doesn't look like it's out of reach if the country gets it's energy goals in focus. Simple metering, categorized and that is understandable to the occupants.

    I think it's a service that should be delivered by the energy supplier; Not the project owner.

    The modeling and building performance will not be an issue pretty soon. There are so many good tools and smart people using them. Once it's built, it's all up to the occupants behavior. I'm as bad as some of the worst of them. It was much worse when we had kids at home. There was, and still is no feedback loop to quantify and show you what your changes in behavior really do...

  17. albertrooks | | #17

    License's are available: HalfAssivHaus
    Micheal & John,

    Have no worries about apparent infringement on my trademarked property: Halfassivehaus, half assive house, half-assive-house in all of it's various forms.

    I'm a reasonable man. I'm willing to entertain granting a license for your use.

    For a fee...

  18. user-980774 | | #18

    A halfass, pretty good house built with common sense!
    I've always thought the Passivhaus Certification was just a ploy to sell overpriced German windows and HRV equipment. All good comments, but the basic disagreement is whether it is better to use very good locally sourced windows and equipment or "certified" windows and equipment from across the pond.

    I quit following all the infighting when no one could justify the 15 kwh/sq meter, REGARDLESS of climate. Talk about half assed lack of common sense! One size does not fit all!

  19. dankolbert | | #19

    Pretty good article
    Martin has raised expectations - the Pretty Good House was the subject of our building science local discussion group (subject of blogs by both Martin & Michael Maines on GBA). I doubt we'll come up with a "proposal." As others have noted (and as Katrin seems to be belatedly owning up to), different climates have different needs. A shocking revelation!

  20. GBA Editor
    Martin Holladay | | #20

    Response to Dan Kolbert
    Once Michael Maines's article is published, I'm going to solicit guest blogs from volunteers who want to write about the "Pretty Good Texas House," the "Pretty Good Florida House," and the "Pretty Good Oregon House."

    Uh oh ... I forgot to ask ... have you guys in Maine already registered for a trademark on "pretty good house" and "PGH"?

  21. dankolbert | | #21

    Registered? Hell, most of us up here can't even read.

  22. user-869687 | | #22

    Monitoring and bragging rights
    Maybe it doesn't matter so much to compare houses normalized by weather data, or itemized by plug loads / appliances / internal gains, etc. If this is about joining the "energy miser" club and membership is based on utility bills, then bragging rights depend solely on that bottom line. For example, is it less meaningful to meet 4.75 kbtu/sf/a only with the thermostat to 63°F? If someone says, my household meets PH efficiency, would you say it doesn't count if they're always wearing a sweater (and maybe a hat)?

  23. wjrobinson | | #23

    I would say if a person stops
    I would say if a person stops buying energy.... BINGO.

    Next problem. 9% property tax increases, and 9% healthcare cost increases. Dwarfs this green planet problemo financially at least.

    $5,000+$15,000 now becomes $20k plus $60k= $80,000 annually in 2027. No 2% pay increases make a dent in these goofy numbers. Try to get a chunk of pre listing Facebook stock or grab some NG fract. land quick!

    aj PGH AFS (armchair and field self-certified)

  24. GBA Editor
    Martin Holladay | | #24

    Response to TJ Elder
    You wrote, "If this is about joining the 'energy miser' club and membership is based on utility bills, then bragging rights depend solely on that bottom line."

    I agree.

    "If someone says, my household meets PH efficiency, would you say it doesn't count if they're always wearing a sweater (and maybe a hat)?"

    Well, it depends. I think the PHPP software assumes 70 degrees F indoor temperatures or something close to it. So if someone has a Passivhaus and chooses to live at 60 degrees F during the winter and wear a sweater and a hat, then their energy use (all other things being equal, and normalized for weather) will be less than predicted by the modeling software.

  25. user-988403 | | #25

    Arbitrary or not
    Even though the 15 kWh/(sqm yr) derived from some calcs for central European climate I have yet to see a non arbitrary counter suggestion. Nobody here argues that California needs less insulation than Minnesota and the PHPP "knows that" too. I don`t argue that a Half- passive house can be a good house but having the standard allows owners to define better what they want and have a 3rd party quality control. It is to bad of cause if the 3rd party does not agree internally :-). Also I believe that if owners who really know what they want, work with professionals who really know what they are doing the standard might not be the optimal choice because the optimal choice is probably unique for each project, even within the same climate zone. After all the Passive House standard brought some good discussions here, some of them seem to be never ending.... . I also hope to see more monitoring and published results. I don`t agree with "Chasing rainbows..." because luckily statistics are pretty well understood.

  26. gusfhb | | #27

    Pretty Interesting graphs

    Things that strike me:

    Actual house to house error goes up dramatically as efficiency goes up. Kind of a 'duh' but interesting. I would be hard pressed to put a foot of foam under my slab when forgetting to latch a window would cost me more.

    Would love to see the year after year

    would love to see which houses are using energy IOW they are blaming occupant behavior[quite probable] but perhaps other things are going on

    The average German house is 10x passivhaus? I don't feel so bad

  27. user-988403 | | #28


    It is not surprising at all that the error goes up as efficiency goes up. The same energy goes out a open window in a efficient house and a not efficient house. Adding this "lost" energy to the total heating energy makes a much bigger difference (percentage wise) in the efficient house than in the inefficient one.

    Sorry I don`t get the abbreviation IOW but most of it is most likely consumer behavior but some of it could be a overlooked thermal bridge etc..

    The average German house includes the existing building stock. The difference is that the energy code for new construction and extensive remodeling is much stricter than here. Here you can still build a house that performs 10x worse than Passive House in Germany not. But you don`t have to feel bad anyway....

  28. GBA Editor
    Martin Holladay | | #29

    What the graphs reveal
    As I said, monitoring data from one Passivhaus won't tell you whether or not the building meets the standard.

  29. user-1089777 | | #30

    Why 15kWh/m2a?
    Martin, Richard (and clearly a whole lot of PH folks),

    The certification metric for Specific Space Heat Demand (or Cooling) has a firm basis in physics. It derives from the calculation of Energy Balance according to ISO 13790, and reflects the point at which it is reasonable and economical to offset the total heat losses of a building with free heat from internal and solar gains. The remaining Heat (or Cooling) Demand required was found to be around 15 kWh/m2a, hence the standard metric. Info on how this applies to other climates can be found here:

    I must also clarify that your statement: 'Space heat must be delivered through ventilation ducts' is a common PH myth. The rare instances when the Heat Load may be low enough to where heating can be supplied through the ventilation ducting is on very small PH projects, and or in climates where winter days are typically overcast. This alternate to the SSHD certification metric can only be applied to residential projects as the intermittent usage of other building types will not allow for sufficient continuous internal gains to maintain thermal comfort.

    It has been repeatedly shown that trying to heat PH buildings through the ventilation system is not typically a good idea. We are used to doing this with our conventional 'blast' furnaces, but when the air velocity and ACH requirements are reduced to the low levels needed in PH projects, delivering heat along with the air no longer becomes economical or effective. Smaller point source heaters do the job affordably and more effectively. There have been numerous papers presented at the PHI conferences documenting this and they're worth seeking out (ask someone in your local PH community to borrow their copy of the International Conference Proceedings for any of the last 4 or 5 years.)

    Since the certification of windows issue was raised, there certainly is a discrepancy in how the PHI calculates their performance metrics for windows and how the NFRC calculates them. This is a simple protocol adoption issue. (See here: NFRC adopted the use of ASTM protocols, while the PHI uses EN ISO 10077-2 and EN673. Some manufacturers have found a simple work-around. ( PHI has been made aware of the 'lost in translation' window inputs for the American PH market. I'm in dialog with folks on all sides and am hopeful an official solution can be found. However, it won't be ready any time soon!

    In the meanwhile, interest and knowledge in the PH concept continues to grow here in the US, despite the recent 'kerfuffles' on all sides. Like Albert, I'm seeing practitioners using the PHPP as the design tool it was intended to be. Projects are 'dialing in' their assemblies and getting creative with 'boxy.' Design is really where the real opportunities to optimize lie, and architects who learn to control the levers of performance will have the most success with PH. Projects where performance is front-loaded into the design, and not added as an afterthought will also be cheaper and easier for contractors to build. Design Build will ultimately be the most successful of all the project delivery methods.

    The PH community in the US still has a way to go before we fully grasp the complexity that the PH standard offers and requires of us. The projects built here so far are all admirable in their attempts to achieve the certification standard, whether they actually made it or not. There will be building failures, and indeed there are already a few projects experiencing overheating problems due to lack of understanding of the shading and cooling parts of the PHPP. However, I'm betting those failures will be fixable (and fixed) because the people I've met in the PH community across the globe are all passionate about quality - or they would never bother to attempt a PH level project. PH projects are also driving the local market to get serious about performance. New products are being introduced rapidly. (Serious Windows has an advertisement that states 'No need to buy German!') Imports will slow down when the local market provides reasonable equivalents, but right now the import market in the PH world is booming. It ultimately won't matter whether people have their buildings 'certified' or not and Dr. Feist himself has stated that he doesn't care - as long as they are modelled and built properly. The PH community is shifting the focus of the building industry to quality, which will not only improve performance, but will also last longer. Now isn't that Phundamentally what every man (and woman) wants?!

  30. GBA Editor
    Martin Holladay | | #31

    Response to Bronwyn Barry
    Thanks for you long and informative post.

    You wrote, "The certification metric for Specific Space Heat Demand (or Cooling) has a firm basis in physics. It ... reflects the point at which it is reasonable and economical to offset the total heat losses of a building with free heat from internal and solar gains."

    As stated, this is an economic assessment, not one based on physics. Many U.S. builders disagree with your assessment that 15 kwh/m2 is "reaonsable and economical." It is easy to choose actual Passivhaus projects where it's hard to see why it is "reasonable and economical" to spend an additional $10,000 for insulation (or Siga tape) to achieve an additional $100 per year in fuel savings. Your definition is circular; it has nothing to do with physics.

    You wrote, "It has been repeatedly shown that trying to heat PH buildings through the ventilation system is not typically a good idea." Then why is the definition of Passivhaus at the very top of the Passipedia web page -- a site I was directed to by Dr. Feist himself, who recommended it as an authoritative resource -- still misleading people? That definition states, "A Passive House is a building, for which thermal comfort (ISO 7730) can be achieved solely by post-heating or post-cooling of the fresh air mass [ventilation air] which is required to achieve sufficient indoor air quality conditions – without the need for additional recirculation of air.”

    You wrote, "indeed there are already a few projects experiencing overheating problems." Those of us who designed and built passive solar houses in the 1970s can see at a glance that this will be a problem with many Passivhaus designs. But we are basing our judgment on experience, not the PHPP.

  31. user-723121 | | #32

    PH and overheating
    I was in the Smith House in November for the 2nd Annual Passive House conference, home tour. The day was sunny, outdoor temp about 30 and it was warm in the house, over 80F I would guess. This home has a lot of south facing glass (high and low) and the direct beam goes way back into the house. The house was filled with a whole bunch of energy enthusiasts (at least 40) so I am sure this raised the indoor temperature a bit (Martin can do the human Btu calc, they probably all had a lot of hot coffee that morning).

    The Smith house would and maybe has benefited with a better trellise/pergola on the lower bank of south facing windows and some additional interior thermal mass. A bit of overheating in the winter in a cold climate is not the worst thing, kind of feels good in January when the outdoor temp is -30.

    I take my hat off to the Passive House folks, they are in large part responsible for the advanced discussion we are having today here at GBA and elsewhere.

  32. user-1089777 | | #33

    Circular thinking
    Hi Martin,

    You're right about the circular thinking in my explanation of the SSHD number. I've reached out to some people who are smarter than I am to help clarify.
    Regarding the issue of heating though the ventilation supply: the definition of PH does not state the fresh air must be heated (or cooled) exclusively in the ventilation ducts. It just needs to be heated at some 'post' supply point. Whether that occurs partially within the ventilation system (and some climates require this) or totally outside the ventilation system is up to the mechanical systems designer. The main point is that the air in a PH only needs to be heated once, because the overall energy loss is so massively reduced by the efficient building envelope. The interior air does not need to be heated, and then re-circulated and re-heated multiple times such as occurs with a typical furnace 'ventilation' system. Is that a little clearer - at least on that subject?!

  33. GBA Editor
    Martin Holladay | | #34

    Response to Bronwyn Barry
    This is just another red herring, I'm afraid. The air in a Passivhaus only needs to be heated once? How do you make sure that happens?

    Let's say a Passivhaus designer chooses to install an electric resistance baseboard heater -- or wall-mounted electric heaters like I saw in Dan Whitmore's Passivhaus in Seattle. Is each molecule of nitrogen and oxygen somehow given a tag, and told that they only get to approach the electric resistance baseboard heater once? And if the same molecule drifts too close after being heated once, what type of Passivhaus contraption prevents that molecule of oxygen or nitrogen from being reheated?

    Whenever you have a heat source in a home, there is a strong likelihood that some of the gaseous molecules of air will get heated more than once. And so what if they do?

  34. lindawhaley | | #35

    I want to play red herring too!
    Naturally there will be air molecules being recirculated and possibly heated more than once (especially if you are fortunate enough to live in a "Passion House"!) Of course there may also be more mundane re-heating of air molecules, but not to worry - we'll get the PH-olice on the case!

  35. Jesse Thompson | | #36

    PHIUS Conference 2011 Rideau House Presentation
    For those actually interested in the specific project at hand, Ryan Abendroth from PHIUS made a really thorough and interesting presentation on the Rideau House and the events that surrounded its certification and the back-checking that went on after the complaint about its certification. He talked a lot about the shading issues that only became clear after the complaint was filed, as well as the thermal bridging issues that resulted from poor detailing. Here is a link to his presentation, no words, but lots of interesting graphics and photos:,%20Ryan%20-%20QAQC%20Vert%20DesignSM.pdf

    The other presentations from the PHIUS 2011 Conference are at this link, there's lots of good things there:

  36. Lyndon Than | | #37

    The Real Story
    The behaviour of people in this article is the real story. I have always been impressed by the elegance and comprehensiveness of the Passive House concept and the PHPP - and consequently by the people who offerred this system to the world. Sadly, I guessed from the first news last August about PHI and PHIUS's split that the the issue had to do with the challenge of the Rideau House Project. I find it amazing that PHI could be so erroneously and negatively influenced by one person's challenge of one project - Perhaps there have been other issues coming to a boil - but still - throwing away PHIUS based on what seems such a cursory review of evidence - of issues which turned out in the end to be of miniscule proportions IE the PHI-PHIUS bond was broken over perhaps half a kWh/m2a - on one project. I can only conclude (and with much compassion) that there is something significantly dysfunctional at PHI.

  37. Mike Eliason | | #38

    One could make a

    One could make a similar conclusion based on the actions of PHIUS over the last year, that it's not the PHI that is significantly dysfunctional...

    In the end, it's probably a combination of both that led to where things are, though.

  38. GBA Editor
    Martin Holladay | | #39

    Ryan Abendroth's presentation and finger-pointing
    Thanks for the link to Ryan Abendroth's presentation. One possible conclusion: all of the various PHPP iterations of this disputed building are relatively close, in the grand scheme of things, and the number of BTUs that these organizations are fighting about is relatively small.

    Concerning finger-pointing: we have two organizations. They are both pointing across the Atlantic Ocean, shouting, "They done me wrong!"

    Sadly, I see plenty of evidence that both organizations are accurate in their complaints.

  39. Jesse Thompson | | #40

    Certification & success
    Ryan was very candid during his presentation. I may have mis-heard, but my memory of the narrative was that the project was not designed from the beginning to be a Passivhaus, but the project goals were instead to be a very low-energy building constructed with only North American building components. It was implied that Passivhaus came late to the design, and that there were many details that would have been built differently if Passivhaus had been the goal from the beginning.

    As well, my impression is that issues like this have been one of the major reasons why PHIUS has developed their PHIUS+ Certification (, which, unlike PHI in Europe, involves site inspection of projects before Certification, because PHIUS is so nervous about "bad" projects leading to controversies like this one.

    Personally, I don't think this project is a failure at all, but instead is a tremendous building caught up in a turf battle between Certification entities, because as you said Martin, we're dancing on the head of a pin with the differences between the range of modeled energy use, let alone actual energy use.

    As well, the 20,000 built Passivhaus in Austria seem to follow the model of this project as well, get building quickly and don't worry so much about precise certification of every single building, too much attention to detailed certification only gets in the way of ramping up the construction of low-energy buildings as fast as we desperately need right now. Since I'm not a Certification entity, I will always bias towards more projects built close to a target, rather than all or nothing. But I can understand why a Certification entity would have to see things differently.

  40. user-988403 | | #41

    $10,000 for 100$/YR?
    Martin, you where throwing some numbers at us earlier I was wondering if they were an educated guess or based on project estimations? I doubt them a little because they do not correspond very well with what I usually see. So if we`d take a approx. 2000 SF house heated with natural gas (5 Cents/kWh now but who knows the prices down the road) you are estimating that it costs $10,000 to bring the project from 25 kWh(/m^2YR) to Passive House !? I think that bringing the project down to 25 kWh(/m^2YR) is already such a huge step compared to normal construction that all it takes for passive house (15 kWh(/m^2YR)) is smart design, detailing and maybe a couple bucks for more cellulose! Nevertheless I am OK with 25 kWh(/m^2YR), if you make that a standard I might be using it :-). How about a standard where the roof area has to be big enough to potentially offset the operational energy?

  41. GBA Editor
    Martin Holladay | | #42

    Response to Philipp Gross
    First, I want to admit that I was pulling numbers out of the air to make a point. (I was thinking of a Passivhaus built last year in Lancaster, N.H. by Ben Southworth. According to Ben's PHPP calculations, that house required an R-78 floor — he ended up using 12 inches of polyiso — and an R-148 ceiling.)

    Here's another real case: Marc Rosenbaum was running the numbers on Claudia King's house in Maine. They started out with 4 inches of polyiso on the exterior of the wall sheathing (with more insulation between the studs), but the house still fell short of Passivhaus. The team calculated that bumping up the exterior polyiso from 4 inches to 6 inches would cost at least $2,880 -- probably more. They decided not to do it, however, because the extra foam would only save 950 BTU/sf/year. I forget the size of the home, but if the home measures 2,500 square feet, that's 2,375,000 BTU per year, which you could supply with a ductless minisplit for about $41 per year

    I'll admit that the Claudia King example shows I was exaggerating when I referred to spending $10,000 to save $100 a year. It would have been more accurate to talk about spending $2,880 to save $41 per year. But you get the point.

  42. Katrin Klingenberg | | #43

    15 is dead. Long live 15.
    Thank you Martin, for a very good article. The Rideau residence is in certification range, I think that much is clear (thanks Jesse for referencing Ryan's presentation above). If in doubt they might just have to kill the one coniferous tree and turn it into biofuels... :)

    I think it is an awesome project and I congratulate the Team Straka to have built this first certified project in Canada in a very difficult climate and best of all using all North American materials and components!!! They have shown that it really is true, you don't have to use expensive European imported goods to get there. This project will help hugely to make the case to the government that Passive House is a valid option for Canada. Well done and keep on building!

    The discussion about the reason behind 15 is a nice segue way into my brand new Klingenblog that is launching today, with more discussion on this topic. The title: 15 kWh is Dead. Long Live 15 kWh.

    Should be fun, to read more go here:

  43. GBA Editor
    Martin Holladay | | #44

    Response to Katrin
    Thanks for your kind words, and congratulations on your new blog and your bold proposal.

    I look forward to reactions from readers.

  44. ecdunn | | #45

    So what
    I, for 20 years, have promoted sustainable building in Northern Arizona and the Flagstaff area. I have designed over 45 passive solar sustainable homes and I have built 30. When I read about the Passivhouse requirements a few years ago, I was pleased to see that the method followed the accepted principles of passive solar design; tight, well insulated, oriented to sun, glass, mass, and ventilation.

    When Coconino County and the City of Flagstaff formed the Coconino County Sustainable Building Program about 8 or 9 years ago, I helped develop the checklist for building a sustainable home. It exceeded LEED as it promoted the idea of passive solar. LEED for residential eventually came around to the idea, but not very much. It was also noted that LEED promoted larger houses to get the max points and LEED homes did not seem to perform as well, even though they might be platinum. I suspect the same could happen with PH certification, if folks are not careful. It becomes a game of chasing points rather than achieving true sustainability. Smaller, simpler homes do this.

    I would not be so concerned about the certification, rather, use the checklists as guidelines for designing and building. It's not the points, it's the performance that counts. I actually have high performing homes that are not certified at all. The occupants are very happy with near zero energy bills, the great comfort and the knowledge that they know how much carbon was emitted in the building of their home. Certification is often used as a selling point for a home, but most all of my clients are in their homes for the rest of their lives so this is not a concern.

  45. AndyKosick | | #46

    It's easy, it's not easy
    15 Kwh/m2 is easily achieved anywhere, you just start turning down the thermostat... I'm just saying:)

    But seriously, a little perspective from the trenches of the vast majority of our housing stock. I like standards as bench marks but as an energy retrofit contractor who generally works for people with modest incomes (that would be most people who live in existing houses) this infighting at PHI is depressing me. Spitting hairs on a house that's more efficient than almost anything I'll ever work on isn't very inspirational. I work very hard to get anywhere close to a pretty good house.

    I for modeling as a guide and monitoring as a certification. That gets the occupants in on it and they're often the biggest part of the equation.

  46. user-869687 | | #47

    Response to Ed
    The beauty of PH is that it's not about chasing points. With LEED-H you have 138 possible points, and just 90 needed for Platinum. Start with a small home and get a 10-point head start. It's certainly possible to hit Platinum even with code minimum insulation, because there are so many ways to score points. I think this reflects a strategy by the USGBC to expand market share by letting people find ways to get good scores, rather than being too rigid and exclusive. PH isn't like that--you really have to follow the recommended strategies to meet the standard. Any project that does meet the PH standard will certainly be exceptional, at least in the context of houses in the US, which generally have a low standard of energy efficiency.

  47. user-869687 | | #48

    Turning down the thermostat
    Andy, that's what I keep saying, but really not kidding. This is a real challenge for people, to say there is not a hard and fast relationship between efficiency and energy use. Say for example that I admitted to not owning a fuel efficient vehicle. Your reaction might be that I must use a great deal of gasoline, because obviously as an American citizen, an adult and living in the modern world, I must spend 12-15 hours a week behind the wheel of a large automobile. However this is not the case. Likewise, in my view it is not a certainty that inhabiting a home with lousy insulation necessitates using a huge amount of natural gas. There is another variable, if we dare to admit. What I keep thinking is how new this idea is, that no matter how cold it may be outside you must be able to maintain 70°F inside your abode. Did Queen Victoria live this way? What about the first 30 Presidents of the US? But these people must have been from a step back on that chart of human evolution, with a lot of body fur, like a wooly mammoth?

  48. GBA Editor
    Martin Holladay | | #49

    Response to TJ Elder
    Q. "What I keep thinking is how new this idea is, that no matter how cold it may be outside you must be able to maintain 70°F inside your abode. Did Queen Victoria live this way?"

    A. "Poor Queen Victoria found Buckingham Palace so cold that she used to take brisk walks along the great corridor to stay warm." (Source:

    So, you're right: Queen Victoria did not live that way. But if you are implying that the Queen was quite happy with the situation, you are wrong. As she would have put it, "We are not comfortable."

  49. user-1017420 | | #50

    Hello. I am in the process of building a GOLD CasaClima house in Italy. Although it will NOT be certified PHI, it will meet most if not all of the standards (ie, less that 10KWH/m2 energy and ACH of 0.6). What I find interesting is that there is something similar happening here in Italy. The founder and Ideologist of CasaClima, Norbert Lanschtner has come to a disagreement with the board of the agency he founded. From what we understand there is a difference of opinion on how the agency should evolve and what its boundaries should be.
    This is very sad. Norbert has committed 10 years of his time to the advocacy of Energy Efficiency and bringing the need for efficiency to everyone's attention. What is disturbing is that like PHI, CasaClima should concentrate promoting the idea and not get involved with politics or marketing. So, if PHI has their noses out of joint because a Canadian product (I'll probably be shot for this!) is as good as a German product, then guess what, so be it. My evaluation of the choice of a product is based on many things. The performance of the product, the local availability (transportation=energy use) and the cost.
    I am a firm believer that if you want to make energy efficient home "mainstream" then they MUST be available to everyone, not just who "can afford it". I've had the argument before. Why should I pay double for a dishwasher that uses less water. It should be other way around to motivate people to buy energy efficient products. The house possibly won't cost less, but it certainly shouldn't cost more, hence the evaluation of product choice.
    Anyway, very valid points in the article. Pity something good gets all messed up with someone proclaiming that "mine is longer than yours!"


  50. GBA Editor
    Martin Holladay | | #51

    Response to Alec Shalinsky
    Thanks for your perceptive comments.

    If any GBA readers are interested in learning more about the CasaClima program, they may want to read this article:

  51. user-1024963 | | #52

    Windows not certified by P.H.
    The complaint was "The project’s HRVs and windows hadn’t been certified by the Passivhaus Institut in Germany, rendering their specifications suspect." Am I correct in pointing out that the product used does not have to be PH certified in order for the project to achieve PH certification, but the PERFORMANCE VALUES of the product do need to be researched & certified. Yes, if the product used already had a PH "stamp", it would leave no room for error. But if it doesn't have a PH "stamp" that product can still be used for PH project certification IF the performance numbers are accurate...sounds like those numbers may not have been altogether accurate for this project. I bet they would be perfect for Kolbert & Maines Pretty Good House :)

    Just pointing out that many ask for pricing on PHI "stamped" windows/products, but end up going with the most economical, high-performing product if the performance numbers are still there ...which seems to be what I'm hearing from most designers/architects/builders these days: "...we are designing/building an almost-PH house..."

  52. GBA Editor
    Martin Holladay | | #53

    Response to Nate Campbell
    The issue is a little more complicated than you suggest.

    To input all of the U-factors and SHGC numbers required by the PHPP software, North American designers have to know a variety of performance numbers for the frame and the glazing. U.S. and Canadian window manufacturers may not have these numbers handy, especially since U-factors are calculated differently in North America than they are in Europe. (For more information on these differences, see this article, Passivhaus Windows, including the comments on the same page.)

    When the numbers are unavailable, many U.S. designers have inserted "best-guess" numbers into the PHPP software. Whether or not this practice is legitimate depends on your point of view.

    The Passivhaus Institut in Germany takes a hard line, and assumes default values (in the absence of values determined in their labs) that are worst-case values. Of course, this approach could be seen as one way that the Passivhaus Institut encourages window manufacturers to get their products certified by their lab. They have a vested interest in getting window manufacturers to obtain the PH stamp.

    This puts North American window manufacturers and Passivhaus designers at a disadvantage.

  53. user-1024963 | | #54

    Response to Martin Holladay
    Yes, but in an effort to simplify this complicated issue...
    I have represented Canadian, US, and European window manufacturers. If a designer of a high-performing project requests a Uf, Ug, or SHGC value and the manufacturer doesn't have them "handy" or can't figure it out, that designer is not going to use my product. I have a hard time believing that any manufacturer can't give an accurate value for the frame and glass of their product, no matter where it is made.
    In regards to this article, was this complaint based on N. American calculated U-values vs. European? If so, there are a lot of projects in N. America using N. American calculated windows for PH projects, which would "render their specifications suspect" all over the country........OR, the issue may be specific to the mfctr's mis-leading & inaccurate information.

    All speculative...just raising the topic. Thanks for your input.

  54. lindawhaley | | #55

    PH Window Psi Values
    Hi Nate,

    The PHI measures window efficiency in a manner that is different than the NFRC and it is this difference that can be difficult to authenticate. For a series I am writing on the PHPP, I contacted PHI for information on just how they calculated the u value of the frame and the PSI g value then posted a graphic to explain it. Also in the article are graphics by Bronwyn Barry, another CPHC, who explains the psi install. If you are interested you can find "THe ABC's of the PHPP - Part 4B Psi-lence of the Jambs" at

    Linda Whaley, CPHC

  55. user-1017420 | | #56

    CasaClima House

    FYI, if you'd like to see what we're doing, please have a look at our blog.


  56. GBA Editor
    Martin Holladay | | #57

    Response to Alec
    That's a beautiful house -- and you get to live in Italy! I'm jealous.

  57. albertrooks | | #58

    Question for Alec
    You're using a red tape on the foil faced batts that I think I recognize. Do you recall what the name of it is? (Yes, I know I'm far too into tape...)

    I really like how you put the logs into use. Great job.

  58. wjrobinson | | #59

    Alec, killer project. Great
    Alec, killer project. Great home, northern neighbor.

  59. user-1005581 | | #60

    German certification for U.S. homes?
    I'm a native Floridian that moved to Germany in 1973 and lived there 29 years until 2002. At the beginning I was a bit perturbed by the German standardization. Looking for a simple record player I discovered that some were “Hi-fi according to DIN 45000" - I don’t remember the exact last three digits. A bit overblown I thought at the time. Kitchen cabinets and appliances (range, refrigerator, washing machine, etc.) were standardized: 60 cm wide, 60 cm deep and 82 cm high. That turned out to be quite handy.

    Germany had a big influence on my thinking. After returning to Florida my thinking was more German than American. I’m very thankful for that influence - especially regarding green building.

    From personal experience during 29 years I can name various aspects of life in which Germany is ahead of the U.S.

    I have not delved into the details of the Passivhaus standards. It is very well possible that they exceed the U.S. standards. Perhaps we can learn from them. But although the break of the German-U.S. bond was perhaps premature and based on a couple minor details, maybe it was a good thing for Passive House to come of age and start making its own decisions.

    Isn’t it a bit extreme to expect U.S. window manufacturers to get all of their products certified by a German organization for use in our country? Who is going to pay for that? All of the buyers of their windows. Out of the approximately 450,000 single-family homes that were completed in 2011 in the U.S. according to the Census Bureau how many were Passive Houses? According to Wikipedia: “As of August 2010, there were approximately 25,000 such certified structures of all types in Europe, while in the United States there were only 13, with a few dozens more under construction.”

    Passivhaus introduced some intriguing concepts and ideas but the focus seems to be extremely narrow about energy consumption alone. I’m hoping to someday make my tiny 600 SF home Tnet-zero-energy home but I certainly won’t be able to pay $335,000 for a copy of this year’s Solar Decathlon winner. That winning home had just one bedroom and one bath in 876 SF. That’s $382 a square foot! As a realtor in southwest Florida I know that that is nowhere near affordable housing for the general population here. That is seven times the cost of some 3/2/2 homes in our area built in 2007. Somebody needs to get in touch with the economic reality in our country.

    A system that completes 13 out of 450,000 homes is not going to make a dent in our energy use. We need a simple system that can be affordably applied to the 450,000 homes built each year. Reducing their energy consumption by 10%, 20% or 30% would accomplish much more than a handful net-zero-energy homes. And please hire an architect that knows something about aesthetics. These boxes with south-facing windows seem to be designed by engineers with no sense of beauty.

  60. GBA Editor
    Martin Holladay | | #61

    Update: Dr. Wolfgang Feist responds to the contoversy
    On February 7, 2012, Dr. Feist responded in writing to the controversies surrounding the Passivhaus certificate awarded to the Rideau Residences. I have quoted from Dr. Feist's response in a new section added at the end of my article.

  61. delfstrom | | #62

    Mr. Feist's response doesn't address the points raised
    Unfortunately Mr. Feist's response does not address the points raised in GBA article. If not hitting exactly 15 kWh/m2 then it is very close, apparently. Yet PHI says "the energy performance was far removed from the Passive House Standard". So what is it, PHI? What is "far removed"? Are we talking half a kilowatt or double the standard?

    Then by referencing Ms. Klingenberg's blog comments questioning the 15 kWh/m2 limit Mr. Feist proceeds to use that as support for how the Rideau Residences do not meet the Passive House Standard. Just because someone is questioning aspects of the standard doesn't mean that they can't do energy modeling or building science.

    I would like to see how the building performs without the arbitrary penalty of downrating independent performance data for the Lifebreath (and windows) since the products are not PHI-certified. If the home passes with the actual test numbers for the ventilator, well, then it wasn't at all "far removed", was it?

  62. GBA Editor
    Martin Holladay | | #63

    More information on North American HRVs
    I just came across this information from one of Mike Eliason's blogs -- it's relevant to the question of the using of ERVs or HRVs that haven't been certified by the PHI in Germany:

    "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 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. "

  63. delfstrom | | #64

    Passive House vs. Certified Passive House
    The upshot is that the Rideau Residences should still be called a Passive House, just not necessarily a PHI Certified Passive House.

    This still puts it firmly in the territory of "30,000 Passive Houses in use worldwide" (source: Passipedia, Examples page) but not in the much smaller and much less frequently quoted number "1,600 Certified buildings" (source: iPHA, Building Certifiers page).

    How many of those remaining 28,400 buildings could actually be certified if subjected to the same level of scrutiny? For that matter, how many of the previously certified passive house projects by a licensed PHI certifier might fail if another party complains to PHI again?

  64. user-1017420 | | #65

    Red tape
    Sorry for the delay. I don't look at this blog very often.
    The red tape is made by Venture Tape from Rockland Mass. You could also use Tuck tape, but I find the venture tape stickier. Don't get it on your lips......
    And thank you all for the comments on the house. I'd like to point out that during the recent cold weather in Europe we were fortunate enough to demonstrate that the house does NOT need a heat supply. We will have a ZERO heat bill this winter. YES!
    All the best.

  65. wjrobinson | | #66

    Neil, 10%, 20% or 30% of
    Neil, 10%, 20% or 30% of savings is not worth it. And is a long ways from PH. A LONG ways.

    PH and PGH are great ideas. And NOT certifying is a fantastic option. Missing PH by a percent is way better than a 30% reduction. I like going PH with or without the paper.

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