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Passive House — The Only Place Where Real Innovation Is Happening?

Passive House Conference Joe Lstiburek Opening Talk History

passive house conference joe lstiburek opening talk historyLast week, Joe Lstiburek gave the fifth annual twitterview from his crawl space. (When he gets back from sailing this week, Peter Troast of Energy Circle has promised to publish the transcript.) One of the pearls of wisdom dispensed by Joe was that, “Passive House is the only place where real innovation is happening.”

Last week, Joe Lstiburek gave the fifth annual twitterview from his crawl space. (When he gets back from sailing this week, Peter Troast of Energy Circle has promised to publish the transcript.) One of the pearls of wisdom dispensed by Joe was that, “Passive House is the only place where real innovation is happening.”

That statement got more retweets than any other that night, so let’s take a look at it. Is Passive House really innovative? If so, is it really ‘the only place where real innovation is happening’? Let’s take a look at the evidence.

Is the Passive House program innovative?

The Passive House program gets a heck of a lot of attention for having reviewed—not certified—only about 100 projects. They must be doing something right to get so much attention with so few certified projects. Is it because they’re innovative?

Let’s take a look.

innovation definition passive house

Superinsulated, airtight building enclosures

This is where the rubber meets the road in the program. The main idea is to reduce the energy consumption of Passive Houses drastically, and that has to start with lots of insulation and air-sealing.

The thing is, this isn’t innovative. By 1985, we’d figured out how to build superinsulated, airtight houses in North America. Don’t believe it? See Martin Holladay’s presentation on The History of Superinsulatied Houses in North America.

Probably the main reason that knowledge didn’t get embedded in our codes and practices was the big drop in oil prices in 1986 when Saudi Arabia opened to taps after years of holding back. When a barrel of oil went from $32 to $11 and the Reagan administration cut funding for energy efficiency programs, the superinsulated, airtight house trend went into hibernation.


window passive house thermal bridge r valueThe Passive House program requires that windows have a maximum U-value of 0.14, which is equivalent to an R-value of 7. (Lower U-values are better; higher R-values are better.) That’s pretty darn good…for a window.

They get to that level of performance with three panes of glass, low-e coatings, argon gas in the spaces between the panes of glass, and frames with thermal breaks. The window sample shown at right is from Zola Windows, which makes some of the best windows for Passive House projects.

Those are all great, but again, we had triple pane, low-e windows in the ’80s. Yes, the materials and assemblies are definitely better, but is that innovation?

Thermal bridges

Thermal bridges allow heat to pass through the building enclosure of most buildings because we don’t require continuous insulation. Building codes say it’s OK to put your insulation between the studs of a stick-built home, so you have 14.5″ of insulation and 1.5″ of wood in every 16″ of a typical wall, floor, or roof. Then there’s also the extra wood around window and door openings as well as at corners and intersections with interior walls.

A typical house has a framing factor of nearly 25%. That means that if you had a square house and put all the wood together, it would take up nearly one whole wall of the house.

Passive House requires minimizing thermal bridging. They even give you a number you cannot exceed (0.006 Btu/hr-ft-°F). Their modeling tools, the Passive House Planning Package (PHPP) and WUFI Passive, are more sophisticated than anything designers had in the ’80s, so they probably do a better job here than the old guys did back in the day. But the old guys knew the benefits of continuous insulation.

Ventilation systems with heat recovery

energy heat recovery ventilator erv hrv zehnder passive houseAirtight homes need mechanical ventilation. Passive Houses are supertight. The requirement for air leakage is a maximum of 0.6 air changes per hour at 50 Pascals (ACH50). Our code in Georgia right now requires 7 ACH50 or less.

If you’re trying to conserve every bit of energy in a building, you don’t want all that energy you used to condition the indoor air escape when you ventilate. So you use a device that allows the outgoing stale air to pass close enough to the incoming fresh air that the warmer air gives up some of its heat to the cooler air. The device that does that is called a heat recovery ventilator (HRV). When the two airstreams also exchange moisture, you have an energy (or enthalpy) recovery ventilator (ERV).

And guess what? HRVs were around in the ’70s and ’80s. They’re more efficient now, and we have ERVs as well, but it’s evolution, not revolution again. Not that evolution is bad. That Zehnder HRV shown above is 84% efficient, about 10% better than a typical HRV, and their best model checks in at 93% efficient.

Minimal energy use

The original idea, I’ve read, was to build the best enclosure you can so you could heat and cool the building passively. That’s no longer true, and mechanical systems are allowed to heat and cool a home as long as they don’t exceed the Passive House limits. The official criterion is that the home needs to use no more than 4750 Btu/ft2 (15 kWh/m2) per year for heating or cooling.

The people pushing superinsulated houses in the ’70s and ’80s may not have had a hard number they were trying to reach, but energy conservation was clearly their goal. Creating a program around a goal for maximum energy consumption doesn’t really seem so innovative.

Is anyone innovative?

Hmmm. Well, if we’re going to limit ourselves to buildings, mainly residential, in North America, then there may well be no true innovators. We know a heck of a lot of building science now. We’ve built a lot of homes and been able to study the various ways they fall short. 

Yes, we have a lot of programs and concepts out there, but I’m not sure anyone is doing anything really new. ENERGY STAR has stepped up its game, but it’s not innovative. LEED, NAHB, net zero…none is innovating, not really. They’re all taking ideas that are out there already and trying to get them some traction in the marketplace.

What IS innovative?

dymaxion house buckminster fullerWhen I think of innovative ideas in housing, I think of Buckminster Fuller and his Dymaxion House. I think of Paolo Soleri and his experimental town called Arcosanti. I think of the very odd houses in my copy of the book Shelter.

The problem with innovation, though, is that it leads to ideas that are often too far ahead of their time. The Dymaxion House never really got going. Even Robert Heinlein, who ordered one in 1945, couldn’t get his order filled. Arcosanti is a beautiful idea, but after more than 40 years of construction, the town that’s supposed to have 5000 people has only about 100.

Maybe innovative is overrated. Or maybe, as King Solomon said, there really is nothing new under the Sun. Perhaps making the old stuff better is really where we should focus our energy.

Passive House makes energy conservation sexy

Maybe it’s just because they’re the new kid on the block. Maybe it’s because they’re trying to take energy conservation further than anyone else in the game. But Passive House definitely has a lot of buzz. I felt it when I went to the PHIUS conference in Denver last year.

Even if what they’re doing is refinement rather than innovation, they’re doing a great work. Some of the biggest problems we’re trying to solve are how to deal with moisture properly, how to ventilate enough but not too much, and how to get the highest performance we can when we build. The Passive House folks are zealots in their attempt to understand and conquer these issues.

If you don’t believe me, just try building a Passive House in south Louisiana. Ask Corey Saft how easy it is to deal with humidity when you’ve reduced your sensible loads so much that you barely need an air conditioner.

Another big issue for some people is how to avoid using petrochemical products like spray polyurethane foam, extruded polystyrene foam, and other plastics. I personally am fine with spray and board foam products used appropriately, as are many in the Passive House movement. If you’re looking for alternatives, though, a company that’s deep into Passive House may have what you need: 475 High Performance Building Supply.

Finally, Passive House is clearly leading the pack by making the best promotional video of any program. It’s from Europe and is slightly NSFW (not suitable for work) because it’s a little risque. It’s in French, though, so don’t worry about the sound unless you have francophones around.

So, yeah, Passive House is really testing the bounds of what’s possible. Whether we call it innovative or not isn’t so important.


Passive House Links

Passive House Institute of the US (PHIUS)

Passive House Alliance – US (PHAUS)

2013 PHIUS Conference – 15-19 October 2013, Pittsburgh, PA


Related Articles

Dr. Joe Lstiburek Surprises Passive House Conference Attendees

Why Should I Care About the Passive House Program?

A Good Window Is Still a Poor Wall



Twitterview (noun) – An interview in which the interviewers ask questions, and the person being interviewed is supposed to respond with answers no longer than 140 characters. The interviewers and attendees then publish the questions and answers through the social media tool, Twitter, usually with a hashtag, such as #bscamp.


Photo credits: Top photo of Passive House in Maryland by Jim Tetro / JIM TETRO ARCHITECTURAL PHOTOGRAPHY. Innovation definition from Photo of window by Allison Bailes. Photo of Zehnder HRV from Zehnder America website. Photo of Dymaxion House (actually Wichita House) from UCLA Design Media page.

This Post Has 31 Comments

  1. i think the ‘innovation’ bit
    i think the ‘innovation’ bit in PH at this point is going to be slight performance improvements rather than drastic performance increases.  
    but there is still some innovation to be had…  
    thermally broken concrete (e.g. for balconies) – schoeck isokorb 
    ultra clear glass w/ ultra high SHGC, uber low U-value that doesn’t entail much upcharge 
    building rehabs reducing energy consumption by over 90% that pay for themselves rather quickly – at least in the EU 
    hospitals or swimming pools w/ significantly reduced primary demands…

  2. Hi Alison, 

    Hi Alison, 
    With 100 passive houses, 200,000 HPwES houses in ten years, vs around 700,000 residential HVAC units shipped last month, “Building Science” looks like a hobby having failed in 35 years to even make it to insignificant in terms of scale.  
    Also, Can we really continue to blame Reagan for “cutting funding to energy efficiency programs” when the programs we have are colossal wastes, stifle “Innovation”, and are run more like criminal enterprises and Ponzi Schemes where we all chip in to buy our neighbor’s air sealing? 
    Certainly having a sleep away camp where guys can go to hold hands, sing Kum Ba Ya under the stars, spark lefties, hang out in attics and discus their hobby, keeps them off the street, and hurts no one, kind of like the old guys who play with toy trains. 
    To me the “innovators” will be the ones who figure out how to take Home Performance from an insignificant Welfare Program to Scalable industry.  

  3. You mention specific
    You mention specific innovative products and vendors so I will risk mentioning our own. Yes, for years I have been screaming that most traditional stick framing is tremendously energy inefficient with a 25% framing factor – thank you for also recognizing that. How would you like a framing factor of 3% or less? Eco-Panels is a truly innovative product with our single piece molded corner panels (also having superior structural strength) – the corner being an almost impossible part of a structure to insulate well. And it is guaranteed to be 100% airtight at the corner. And there is zero thermal bridging at the panel joint. We often see blower door ratings that exceed Passive House’s arbitrary standards of 0.6 ach50 – recently seeing one of 0.282 ach50 (the lowest rating we have seen in the US). 
    There is a reason the European founders of the Passive House movement have distanced themselves from the PHIUS group – and we have caught them disseminating demonstrably incorrect information in pursuit of questionable dogma. 
    The point I am trying to make is if you focus on the basics, and use truly innovative products, yes you can far exceed your energy efficiency goals and you don’t have to adhere to the often arbitrary dogma (Lstiburek’s word’s, not mine) of the passive house movement. And you could do it for a lot less money too! Isn’t that the whole point?

  4. mike e.: I
    mike e.: I look forward to seeing your PH projects in the Pacific NW when I’m there next month! 
    Charles L.: I actually think it’s a good thing that PHIUS split from the European group. The latter is too rigid and doesn’t understand that we have far more climate variation in North America. I haven’t been involved in the discussions, but I believe PHIUS is now evaluating everything about the program in an effort to keep the good stuff and throw out the stuff that doesn’t work here. 

  5. If I had a building science
    If I had a building science blog as good as yours and were writing about Dr. Joe’s tweet, I might have titled it “We Don’t Need No Steenking Innovation, We Need Implementation!” 
    Your article above states that very thing, in essence. To paraphrase the $6 million dollar man, “we have the technology, we can build it better.”  
    That in our day we still build brand new tract homes with flex duct strung carelessly about a ventilated attic, that many have little to no roof overhangs for shading and wall protection, that many shamelessly orient nearly an entire facade of glazing due west, pierce their ceilings full of recessed lights, place unsealed, non-insulated pull-down attic stairs inside the house and air handlers either in attics or garages…in spite of wonderful innovations in building science over the past several decades…blunders like these and other egregious errors in design and construction continue apace. 
    So what must change in order to see more implementation of these decades of innovation?

  6. There is one real innovation
    There is one real innovation which you are slow to accept. You mention a problem as “to deal with humidity when you’ve reduced your sensible loads so much that you barely need an air conditioner.” 
    For a solution to just this problem, you should look at Thermastor’s recent product the Ultra-Aire SD12. 160 watts. 184 pints/day water removal. 4300 BTU/hr COOLING.  
    Remember that in a recent article “All About Dehumidifiers”, there was a lament about the heat load added by all other dehumidifiers. 
    I admire the Thermastor products for their efficiency. They are not for everyone with their high cost, but they are most definitely innovative.

  7. PJ, I’m not sure exactly what
    PJ, I’m not sure exactly what your rant is about. That the ratio of two specific home performance programs is too low in relation to the number of HVAC units being installed in America’s housing stock in one month? That’s kind of a strange metric. 
    As far as our government funded ponzi schemes, this is typical of government funded programs in all kinds of sectors. The idea is for government to help move new ideas and technologies (that are seen to be beneficial to our country) to market acceptance where they can then stand on their own and the subsidies discontinued.  
    Of course it doesn’t always play out nice & neat being the government & all but hey, it’s the government not a Swiss watch factory… 
    In this case the alternative is for us all to join the ponzi scheme of building more power plants to power the non-subsidized energy pig houses. 
    I would argue the point that these programs stifle innovation. No program is perfect but I see a lot more innovation happening with them than without. It give people a frame work to work in and expand on. 
    BTW – didn’t you have some info. on problems that were seen with the Nest thermostats? I meant to ask before if you could share a link. I would appreciate it. 
    Allison, we are currently working on a passive house in coastal NC and I’m seeing lots of innovation. Mostly with our systems, there are many answers we don’t have which is definitely not the case with our other projects. I hope to be presenting a case study at ACI next spring. As far as I know it’s only the 2nd PH in a hot/humid climate. They made some really obvious mistakes with the house in Louisiana IMO. When I look at it I really don’t know what they were thinking.

  8. M.Johnson, that product is
    M.Johnson, that product is not the answer. There will be lots of time when we need dehumidification with no cooling. That unit provides 1/3 of a ton of sensible capacity. So we’re still stuck with a choice of a dehum. that cools at 1/3 of a ton or one that adds sensible heat. 
    BTW, do you happen to know how that compares to say, a mini-split in dehum. mode? I see “pints-per-day” used to quantify dehum. performance but heat pumps just list sensible ratio and even that info. seems lacking. How can you have a fixed sensible ratio for a variable speed system?

  9. @Skye, you want a dehu that
    @Skye, you want a dehu that heats, or one that cools? Take your choice. There is only one in the latter category, so far. Nobody claimed it would solve every problem, but it directly addresses the problem quoted. 
    It would be very interesting to see performance data on mini-splits, or any split system for that matter. “Pints per day” could be calculated for a given set of operating conditions, but that unit is not conventional for the AC industry. As I see it most of the HVAC industry regards humidity control as an afterthought, that tends to explain considering SHR (sensible vs. latent heat removal) as a constant when it is very much a variable. Trane Corporation offers some tremendous charts of sensible vs. latent cooling at different air flows, indoor humidity, and indoor and outdoor temperatures. I would like to see any such tables of information for other brands, too.

  10. …and to think that my
    …and to think that my innocent little question Tweeted whilst sitting 3 feet from Anschel would create so much buzz….. 
    Another great post Allison! Congrats on your 500+ Blog postings!

  11. The innovation in PH was
    The innovation in PH was largely born in Sweden. Holladay’s presentation on Super-insulation linked above barely hints at that. But here is the kicker. North Americans may have kicked around building houses like this at the time. The Swedes actually did it. They have a mature housing market based on these premises. We clearly do not. You can nit-pick over who came up with what first, but it means squat if your housing industry did not listen to you in the first place. 
    This is not simply a petty argument over who was first, and whose innovations count, and whose don’t. What is important here is that techniques are vetted only by building thousands of houses this way to see what shakes out as what works and what does not work. That vetting has happened in Sweden to the tune of 40+ years of refining innovation. I’m sorry but this is what is lacking in Mr Joe’s advice, and the advice of his colleagues at BSC. Case in point elsewhere is there characterization of Nordic style walls – interior vapor control, layered thermal breaking – as something that was tried and abandoned in the NA market, hence they present this exterior insulated “Perfect Wall” as superior art. It may be perfect for building scientists, but not for builders. They cite difficulties with creating air-tightness – read rim joist conditions – as reasons the Nordic style walls were abandoned. But in fact the Swedes overcame these difficulties, years ago, simply because their techniques were vetted and refined by 40+ years of building houses this way.  
    Instead we have to reinvent building science anew. Don’t believe it. The innovations in Passive House have all been vetted in Sweden. In Sweden these techniques have graduated to industrial production housing. In Germany and the US Passive House presents these innovations as a one-house-at-a-time custom design process – the antithesis of the NA housing industry. You want innovation – PH class insulation levels and air-tightness in every house for every home buyer. That is innovation. The rest is BS.

  12. Perhaps innovate, as a verb,
    Perhaps innovate, as a verb, is applicable. 
    [in-uh-veyt] Show IPA verb, in·no·vat·ed, in·no·vat·ing. 
    verb (used without object) 
    to introduce something new; make changes in anything established. 
    The last bit there, make changes in anything established, is the important part. Whether Passive House achieves innovation under that definition will have to wait for the future. 
    If they can change the way a significant portion of houses get built that will count. As of now I’d still think of them as a boutique system.

  13. I agree that PH is nothing
    I agree that PH is nothing new or especially innovative – unless you look at the significant evolution in high performance products it has inspired over the past 20 years (albeit mostly in Europe, but now spreading here and elsewhere.) You’ve argued that we already had 3-pane windows and HRV’s, but none of these were mass-marketed or readily available until PH came along and pushed the market.  
    The real innovation by the founders of the standard was the creating of the PHPP, an ingenious tool that anyone could learn to use. It is made more useful because it is accompanied by a global training and support network and ongoing research available to all. By using this tool, owners, architects, engineers and builders can ensure their buildings will perform as well as possible – despite the capricious nature of occupant behavior variances. An extra bonus is that your building will also meet the essential basics of ANSI/ASHRAE Standard 55, so eloquently outlined by Robert Bean on this very blog: Sweet!  
    As a previous commenter noted, many previous efforts to promote high performance building have failed dismally. Despite the tragic political scuffles here in the US, Passivhaus remains a Bright Spot. Globally, 6748 projects have been certified, with thousands of others built, but not submitted for the optional rubber stamp. ( And a vast number of them are not simply just ‘houses’: 
    Lastly, it is important to note that there is a massive groundswell of activity happening all across North America, beyond the purview of PHIUS. A very active network of regional Passive House organizations have all chosen to remain independent from the PHIUS/PHAUS structure. Some are actively ‘neutral’, while others are visibly aligned with the organization that set the standard, the Passive House Institute.  
    Whatever your take on the ‘special US climates’ issue, I’d encourage you to broaden your perspective on where PH is heading and make sure to not discount the 1000+ members of the regional PH organizations operating across the North American continent. They’re collaborating quite nicely under the umbrella of the APHN. (

  14. I think there’s something to
    I think there’s something to be said for a program that is all about performance based metrics over prescriptive pathways. Builder’s have been telling me for years which prescriptive requirements don’t work for them and codes are also moving slowly in this direction. While PHPP modeling isn’t easy, the end result fits my definition of “innovative”.

  15. I just received my CPHC 3
    I just received my CPHC 3 days ago from PHIUS. I participated in the first class that conducted Phase I of the training virtually and Phase II “in person”. I took Phase II at Parsons in NY and completed the design portion of the exam at home over a three week period. My point? Discussion of innovation should not just be in the context of the “product (low energy buildings)” but in the whole ecosystem that gets us there. This is where I think PH is making purposeful strides.  
    PHIUS is working on WUFI Passive, a window performance database, point thermal bridge and 3D heat loss modeling tools that are affordable among other things.  
    PHI just released PHPP 2012 which is a huge jump forward as they begin to further acknowledge the international appeal of the standard they founded.  
    As stated above, they also do a great job of organizing themselves, mentoring each other and organizing exchanges of information and lessons learned amongst their professional corps.  
    I chose to go the PHIUS route instead of PHI because I have enormous respect for Katrin and wanted to learn from her, (I also suck at conversions) but both tribes want the same thing and are rigorous in their approach.  
    I would like to say though, at least in my training and experience, there is nothing “arbitrary” in anything the PH folks do. It would be considered inefficient to do so 🙂  
    Thanks for doing what you do Allison. Hope we get to meet at some point.  

  16. I think what AB3 is getting
    I think what AB3 is getting at is that PH is evolutionary rather than revolutionary. PH is all about sweating the details to an extreme degree so as to eke out every possible Btu and kWh of energy conservation. 
    But, I must ask – At what price? What is the cost differential between a “Pretty Good House” and a PH? Is it really worth spending tens of thousands of extra dollars and weeks of design review in pursuit of an additional $10-25 in annual energy cost savings? 
    Put another way, what if we, instead of engaging in laser-like focus on making one project PH- certified, instead diverted the incremental dollars to weatherizing 20 or more existing homes? The energy payback would almost certainly be 10-100x. 
    Live simply, so that others may simply live.

  17. I respect Passivhaus for
    I respect Passivhaus for showing performance levels that can be attained. But, it – and all of us – still take as given that construction will remain a craft industry w/o substantial opportunities for what Burton Goldberg called “Mass Customization”. Passivhaus doesn’t seem to be a route toward better construction systems in which quality is designed in, rather than inspected in. An one example, just think about the number of ways that windows can be installed wrong, because there are so many details that must be done right to control moisture. Like modern cars, we need to think about how to vastly reduce the possibility of incorrect assembly. EOR (End of Rant)

  18. “But, it – and all of us
    “But, it – and all of us – still take as given that construction will remain a craft industry w/o substantial opportunities for what Burton Goldberg called “Mass Customization”.” 
    This is ridiculous. The Swedish housing industry in fact routinely combines industrial production with individual customization, while attaining PH like numbers.  
    The only innovation in PH is the PR. And the North American compulsion to reinvent the wheel only means we will likely ignore vetted solutions that have already gone before.  
    How can we be so unselfaware of this behavior? Did the US really need to create its own PH? Do NA building scientists need to grope for new “perfect” ways to build a wall when better ones are already in common use elsewhere? 
    The innovation happened, is still happening in Sweden. PH and Germany is simply culturally less bashful about bragging. NA needs to wake up.

  19. At it’s core, the ph Standard
    At it’s core, the ph Standard is just the “holy trinity” of insulation, airtightness, site characteristics: -What they yield in heating and cooling load. It has nothing o do with building enclosure type.  
    The arguments about assembly type, window placement, diffusion profile and material choice are pointless. You either have the skill to design an building that wont fail, or you don’t.  
    PH fits a “one off” project or it fits production like Onion Flats equally as well. -Energy loads are independent of production efficiency. 
    Arguing for PGH vs PH is not uniquely American either. It’s a tough standard. It’s not about saving that extra $25/ year. Thats simply a finical decision. Americans are not the only world citizens who are open to softer standards. If you can’t get your single family home to model… Quit complaining. Your really building something far more extravagant that the planet can afford, and that the vast majority of the world’s population get to live in. 
    Saying PHI is not relevant in NA is an immature statement. (Allison: This one’s or you to consider) The standard is adoptable worldwide. Here is the study that looks at modeled projects from intensely cold climates to intensely warm: 
    PHIUS is still working with the same metrics (15kw/m2, 0.6ACH50…) because they are vetted metrics. Coming up with an adaptation is going to be a pretty slight change from the original.  
    Allison, When your out in Seattle give a shout. Mike and I can tour PH projects with you and end the day with a beer. Good quirky fun! 

  20. To reiterate what Albert
    To reiterate what Albert stated, the physical properties of air, water and energy transport that drive the PH standard are the same universally, whether you’re in Germany, the US or South Africa. However, what does change is climate and with different climates come different considerations for obtaining human comfort. This is where PHIUS, I think, would have to tweak the acceptable standard would they desire to do so. In my very limited experience both PHIUS and PHI approach a building with the idea of “how do we achieve maximum comfort at the lowest possible energy budget, for the least amount of money, without using materials that undo all the hard work by being manufactured in such a way that they do harm.  
    Everyone seems to harp on the fact that unless PH is “scalable” it’s a waste of time. I would argue that PH is a design approach, not a commodity. Housing is a commodity, but better housing, truly sustainable housing will derive only from mass acceptance of good ideas and executed by people willing to tune out the peanut gallery. 🙂 I’ll hold up the good folks at Onion Flats and their most recent annoucement as proof of concept.  
    I’d open an invitation for you to come to Philly as well. Great things happening here! We’ve also got a brewery nearby called Dogfish Head (maybe you’ve heard of it) that isn’t half bad.

  21. But Albert misses my point.
    But Albert misses my point. Its not the assembly type that is the question, its the NA propensity to reinvent the assembly, to reinvent PH – that is the point. 
    PH certification is not scalable, the principles are. The principles have achieved scale, years ago, in Sweden before there was even such a thing as PH. 
    NA has its collective head in the sand on this. The fact that PH is being discussed as Innovative rather than Derivative is evidence.

  22. One thing this discussion has
    One thing this discussion has done is make me go take another look at PH. In general I like the mostly results oriented approach. While I still don’t expect PH to become the de facto building norm it could well drive innovation in standard building practice. 
    One possible scenario. A clever builder builds a few PH buildings and realizes along the way that (s)he has come up with a very expedient air sealing routine. That method, applied to conventional techniques allows production builders to regularly hit, say, 1.5 ACH/50. It’s not 0.6 but it would be a big step forward. 
    My point is; don’t look for the innovation in PH, look for the innovation that comes out of it.

  23. Speaking of results-oriented
    Speaking of results-oriented approach, the one thing that continues to bug me about the PH standard and certification is that it is based on modeled performance only. I appreciate the rigor and accuracy of the model (PHPP) but the rigor of the standard would suggest that certification ought to be based on actual measured performance. Or at least there ought to be a requirement to submit measured performance data (incl. utility bills)for say two to three years of building operation. People serious enough to be building to this standard are likely collecting the data (or ought to be) so this would not be an onerous requirement and again I would argue it’s consistent with the rigor of the standard. To my knowledge, the LBC is the only standard that requires this at present and I beleive that is a great credit to the integrity of that standard.

  24. How much data is enough?
    How much data is enough? Yikes people. I’d wager there’s more monitored data collected on Passive House projects around the world than on projects for any other certification. (Easy to find if you care to dig a little.) I’ve worked on two that are being monitored up the Wazoo by the DOE, and there are dozens more across the globe.  
    I too appreciate the rigor of the Living Building Challenge, but given that there are only 5 of them (?) in the world to date, this standard is more aspirational than practical. Not sure it is scalable either and I’ve heard an architect who designed one claim challenges with cost effectiveness.  
    This is a classic case of the perfect being the enemy of the good. I wish you the best of luck finding a perfect standard – and a great place to put your dehumidifier. 🙂

  25. Brownyn, 

    Not a problem. My point was that the standard is really great – it sets a high bar and is worthy of pursuit – yet actual performance matters more than predicted performance and the reality is that many models do not accurately predict actual performance. AND many buildings are not operated as per the design. If the PH standard is considered a design standard, then it’s probably appropriate to leave operational data out of the certification process, however still it would be useful to have that information. It would help in continuing to validate and improve the modeling software as a tool.

  26. Allison, 

    Thank you for the mention of 475 High Performance Building Supply. Whether, incremental, revolutionary, innovative, derivative, disruptive, scaleable or no – Passive House, it seems, has supercharged a much wider audience in building science and the possibilities of low energy building in the US and many places around the world – Sweden excepted of course!;) – starting with the center of the known universe, The New York Times.  
    We feel lucky to wake up every day and participate in this exciting transformational time.


    Awesome post Allison!   
    Great comments.  Particularly poignant to me was P, Cameron, and Kurts.   
    Pj, crazy to deify a meaningless amount of projects and ignore all the jobs being redone wrong.  
    Cameron – “We Don’t Need No Steenking Innovation, We Need Implementation!”  Allison, need an editor?  
    Curt, frustrating to see OCD over meaningless increments when there is so much opportunity to take huge slices out of consumption in existing buildings.  
    This article about Rick Chitwoods work illustrates the path I wish we could all get behind –

  28. Wow! What a great discussion.
    Wow! What a great discussion. Thanks for all the comments, everyone. I think the the passion here, on all sides, indicates that PH is definitely having an impact, at least on how we think about these high performance homes. And yes, perhaps I didn’t consider all of the ways that PH is/can be innovative. I haven’t played with the PHPP or WUFI Passive yet, so maybe that’s where PH is most innovative. Or perhaps it’s as Bill Smith said: “Don’t look for the innovation in PH, look for the innovation that comes out of it.” 
    Albert Rooks, I look forward to getting together when I’m out in Seattle next month. I saw Sam Hagerman recently and may take a trip down to Portland as well to see the PH projects there. 
    Alex Sawyer, when I make back to Philly, I’ll let you know. I haven’t been back there since I moved away in 2000 after two years on the Main Line, so it’d be nice to go back for a visit. We were just talking last night about a high-gravity Dogfish Head beer that you apparently can’t get outside the Philly area.

  29. Attaining Passive House
    Attaining Passive House standards doesn’t require big bucks, just proper research. Windows is what makes or breaks a passive house design. Triple pane windows can get pricey but one can get uPVC windows like Intus which will give you excellent ratings: U-Values of 0.17, AI ratings of < 0.03 cfm/ft², and most importantly SHGC of 0.37 – 0.60 which will work for a wide range of climates.

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