A Climate Action Turning Point!

That's friend of PHIUS and visionary NYC architect Chris Benedict (l) with Katrin Klingenberg.

That’s friend of PHIUS and visionary NYC architect Chris Benedict (l) with Katrin Klingenberg.

On October 29th I was fortunate to attend the NYSERDA low carbon and zero energy Buildings of Excellence Awards at the Building Energy Exchange in New York City. What a terrific time for projects that are about to and that have employed PHIUS+ passive building standards as baseline to get to zero energy ready! I counted at least 10 PHIUS+ project teams in NYSERDA’s three categories, Early Design Stage, Substantial Completion and Completed, that were awarded up to 1 million dollars for their projects!The awards were announced on the 7th anniversary of super storm Sandy, not a coincidence, as a reminder for urgent climate action. Seven years later, NYC is leading by action and is putting itself firmly on the path of global leadership in building energy and resilience. Thank you to an amazingly dedicated NYSERDA team for making this happen!

The week before the event, I keynoted the Boston Passive House Massachusetts Symposium to talk about the evolution of the PHIUS+ certification suite for passive buildings, and why they provide such great value on the path to ZERO. Here as well, political action was taken to combat climate change: MassSave staff announced significant incentives for low carbon and zero energy buildings and significant additional incentives if project teams go for passive building certification for their hi-rise residential projects. Certification requests from Mass have increased manifold as a result. Massachusetts in not far behind NY State in political will, turns out.

And just a few weeks before the Boston event, it was gratifying to find that at the Getting to Zero Forum in Oakland, California, passive building was simply understood as the logical starting point on the path to ZERO, no questions asked. During one of the plenaries the ASHRAE speaker proudly introduced the new ASHRAE standards committee: 227p Passive Building Design Standard. That was great news and evidence that ASHRAE is moving on the topic.

During the lunch plenary on day one the National Renewable Energy Laboratory featured PHIUS board member Mary Rogero’s students presenting their Solar Decathlon winning PHIUS+ Source Zero energy school design. For the closing plenary, California’s Commissioner Andrew McAllister presented on his recently completed and only recently occupied zero energy passive house in Berkeley and the benefit of energy independence. He had electricity while PG&E had shut off power supply to prevent fires, a consequence of climate change, to most of Berkeley including the entire Berkeley Campus. He was followed by Greg Hale, from NYSERDA, who spoke about applying the Energiesprong passive plus zero energy retrofit approach that he is spearheading in NYS and other zero carbon measures taken by the city.

And while most of the building action seems to be happening on the East Coast, quietly behind the scenes advocates have been working hard to get passive building into codes all over the country. When PHIUS was first established our lofty mission was to make passive building code by 2020. As ambitious a goal that was then in 2007, we have made significant progress toward it, and have paved the path for national success. NY State has included passive building as an alternative compliance path into the next stretch code and Washington State is on a similar path. Massachusetts has included an alternative compliance path for passive buildings and verification tools (no double modeling required) and Washington, D.C. also has included an alternate compliance path for passive buildings in their about to be launched ZERO Energy Code.

Most significant of all those developments is the establishment of the ASHRAE 227p standards committee. If successful they’ll created a passive building design standard that takes the best pathways from all existing programs and develop an even better, easily adopted design standard globally. That committee has now started its so very important work. The ball is rolling! Stay tuned for more!

Exciting times, indeed!

 

 

 

 

A mid-cycle tweak of PHIUS+ 2018

image-3

Space conditioning targets have been adjusted to reflect a statistical ‘Inclusive Fit’ rather than ‘Best Fit.’

PHIUS officially launched the PHIUS+ 2018 Passive Building Standard just over a year ago at the 13th Annual North American Passive House Conference in Boston. The passive building market seems to approve: not only have we gotten a lot of positive feedback from CPHCs and other design professionals, but PHIUS+ Certifications continue to increase. The most notable upgrades from the PHIUS+ 2015 standard add nuance to the space conditioning targets, adjusting them for building size and occupant density – passive building professionals do seem to appreciate this.  Another notable upgrade provides tiered source-energy targets and methods to hit those targets, depending on project goals.

Through the end of September 2019, PHIUS certification staff had the discretion to grant an exception for one of the four main space conditioning target criteria, as outlined in PHIUS+ 2018 Passive Building Standard-Setting Documentation, page 6. This allowance gave teams with projects already in planning some assurance that their efforts would not be wasted if their designs could not be revised to meet the new targets.  If a project was severely constrained on meeting a target, a “mulligan” could be granted based on majority vote from the certification staff. This also allowed flexibility in case the targets didn’t pan out in the real world even for clean-sheet designs.

Read the Full, Detailed Tech Corner Article

This “3 out of 4 ain’t bad” provision has now come to an end, and we have learned a lot from the many projects that have gone through the process. These case studies have allowed us to complete a mid-cycle evaluation of the standard. Determining optimum performance targets is an iterative process, and gathering feedback for future improvements is part of it. Thank you to all the teams that have certified to PHIUS+ 2018 helping us to dial in these improvements.

Moving forward, space conditioning targets have been adjusted to reflect a slightly different statistical fit from the original space conditioning target-setting process — an ‘Inclusive Fit’ rather than ‘Best Fit’ line. These updates will not disqualify any previously submitted projects in the PHIUS+ 2018 Certification process, as they are more inclusive than before. One sample graph of this is shown for the Peak Heating Load.

The Space Conditioning Criteria Calculator has been updated.

The Space Conditioning Criteria Calculator has been updated.

The resulting updated targets will be:

Cooling Demand = Original Target + 2.81 kBTU/ft2yr 

Heating Load = Original Target + 0.77 BTU/ft2hr

Cooling Load = Original Target + 0.45 BTU/ft2hr

The PHIUS+ 2018 Space Conditioning Criteria Calculator v2 has been updated to reflect the updates. Note the ‘v2’ at the end of the naming convention. 

Note

  • Projects with a contract date before October 1, 2019 may utilize only one path, (1) Use the updated calculator ‘v2’ or (2) Meet 3 of 4 space conditioning targets as described above.
  • Projects with a contract date after October 1, 2019 may only use the updated v2 calculator.

More details on this, as well as the graphs supporting the statistical analysis can be found in this Tech Corner Article

 

Countering a policymaker’s concern regarding passive house

We recently heard from a PHIUS constituent who had these comments about an experience with a policy maker who was skeptical about passive building:

In recent discussions about building performance compliance options for our city’s Stretch/Green Code, a committee member raised a concern about a provision for passive house design in commercial projects. He thought that current modeling software isn’t reliable enough for reasonable accuracy and cited it as a “fatal flaw.”

Monitored energy use is tracking closely to WUFI Passive models.

Click on the image for a pdf report: Monitored energy use is tracking closely to WUFI Passive models!

Knowing that there are large and small commercial passive house projects being successfully built, I hope you can speak to his concern. The more specifically this can be addressed – the good and the bad – the better.  We are strong believers in passive house design but need to confidently understand how reliable the available technology is before adding it to our building codes.

Essentially, then, the question many policy makers have is this:

Is Passive House Certification too Risky for Code?

Short answer No.

PHIUS+ Certification is based on the same science, data, and energy programs that building codes are built on. However…

Our community is indeed successfully designing and certifying residential and commercial buildings to the PHIUS+ Passive House Standards.

We have two terrific resource sites for both applications and with great examples. Here are the links to them:

  • https://multifamily.phius.org/
  • https://commercial.phius.org/

WUFI Passive, the design/certification and energy modeling software, has proven to be accurate in predicting energy use. We have the largest pool of certified projects in North America and actual measured data is available for many of those projects.

Where we have measured data,we have found that on average we achieve modeled vs. measured results of +-7%, which is the best I have heard of in the energy modeling industry.

That said, there is much confusion out there regarding two passive house certifications. PHIUS Senior Scientist detailed the substantive differences between PHIUS+ and the European approach. In short, ours is a climate-specific passive building standard developed under a DOE grant for North America that has proven to produce very accurate predictions (here is a link to the NREL publication: https://www.nrel.gov/docs/fy15osti/64278.pdf).

The German Passivhaus Institute uses a different standard, not derived from North American climates but instead from only one central European climate (one set of standards for all climates in the world). They also use a different modeling tool, a spreadsheet called PHPP. They have to my knowledge very few projects certified to date in the commercial and large MF residential sector in North America and have not published any modeled vs. measured data.

We initially used their tool for our projects and found a significant difference in modeled vs. measured performance. Overheating in summer was also a problem. In our experience, the performance was off by 25-30% pretty consistently from what was predicted by PHPP. That’s why we switched to a different, more accurate methodology and modeling tool.

So, to the policy maker who raised the concern, I would agree that the PHPP and German standard do have a problem in North America. I do not expect that policy makers take my word for it, either. We encourage code and other officials to vet the standards and design tools carefully before including them. And to all of the PHIUS community who are fighting the good passive building fight, we will be happy to provide you data that proves the performance of the PHIUS+ standard and the WUFI-Passive modeling tool.

Kat

 

Passive Building Standards–What about Embodied Energy/Carbon?

GWPHIUS Senior Scientist Graham Wright is back this week, this time following up on a comment made to his One Cereal Aisle, Many Cereals post from last week. Reader Sarah Larsen (thanks Sarah!) asked about embodied carbon issues. The answer, we thought, deserved its own post, and we hope, discussion.

First, here’s Sarah’s comment:

Graham, thank you for such a thorough and thoughtful post. As a licensed architect, and CPHC I am already inclined toward the PHIUS methods, but continue to be curious about the nerdy differences, how, and why they came to be. I am also incredibly happy with the relationships being developed between PHIUS and code/regulatory agencies; it is critical that energy-efficient building practices spread beyond the geeky few.

The graph shows per capita energy consumption (kg oil equivalent) vs. per capita GDP, PPP (current international $). The size of the bubbles denotes total poulation per country. All values refer to the year 2011. Courtesy European Environment Agency.

The graph shows per capita energy consumption (kg oil equivalent) vs. per capita GDP, PPP (current international $). The size of the bubbles denotes total population per country. Click to enlarge. Data from the Eureopean Environment Agency and the World Bank.

With that said where is the EMBODIED CARBON calculation in our standards?? I can’t stress enough how important it is that we take this into consideration. There are PHIUS certified buildings being developed touting their energy and sustainable credentials who are using products with CO2e paybacks that will almost certainly never be met. We have just 10 years to get this right – a 90 year ROI is not going to cut it! I am very much afraid that if we develop code requirements with blinders on to anything but energy *consumption* we will have the reverse impact that we are working toward – climate catastrophe – by packing our buildings full of foam rather than thoughtfully balancing carbon footprint throughout a life-cycle assessment (LCA).

LCA has some growing up to do, but tools such as Tally are already making better, more broad-thinking choices available to anyone who cares. It is critical that leaders such as PHIUS be talking about embodied carbon and the up-front resource demands of our built environment. I think we could adapt Michael Pollan’s advice on eating as the best way to consume other resources: Build efficiently; not too much; use mostly plants.-– yours in climate-conscious building – Sarah Larsen

Now, back to Graham:

We are aware of the issue but feel we are not yet to the point where we can outright standardize, that is, make hard and fast rules. The Norwegian Institute for Zero Emission Buildings came up with some different definitions depending on how many building life cycle phases are included.

We can move more aggressively to put up some resources and guidelines. There are a couple of books I have found that seem to be helpful for making design decisions:

Most of the thinking I have seen focuses on materials, but I am not convinced that is a broad enough view of it. Suppose one uses low embodied carbon materials but this requires a lot of expensive skilled labor. The money paid for that fans out into the general fossil-powered economy, which has a certain emissions intensity per dollar, so there are emissions associated with all that economic activity, so maybe you don’t come out ahead.

From that point of view, low-cost construction is low-emission construction, and everyone is trying to do that already. I remember back in 2013 or so, the IEA or the EIA put up an interactive data browser that let you see what they were thinking in terms of scenarios to limit warming to 2 degrees C. It was clear that they were not counting on much of a contribution from the building sector. It’s pretty clear that the reason for this is that the turnover of the building stock is too slow, there just isn’t enough time anymore.

As I recall in their 2 C scenario for the U.S., almost half the total savings came from decarbonizing the generation of electricity. The “electrify everything” movement has strengthened since, Architecture 2030 seems to be on board with that, recognizing that anything done in new construction standards doesn’t do anything about the existing buildings, which is most of the problem within that next-ten-years window — so the priority is to stop emissions from existing buildings by electrifying. This is part of the reason we modified the overall energy criterion for PHIUS+ 2018 — it allows for off-site renewables now and that is compatible with the “electrify everything” idea. Some people, like ILFI, go even further and just ban all combustion from building operations.

But back to the embodied emissions. Here is an idea I had about how that might be written into a rule. Let’s call it PHIUS+ Equity & Carbon 😀

It would address both equity and embodied energy/emissions with adjustment to the Source energy limit based on construction budget, on the idea I mentioned above, that embodied energies/emissions are roughly indicated by how much money is being spent, along with the emissions intensity of the national economy.

The adjustment would be based on the idea of limiting the total operating + embodied, so, operating + embodied < 714+221 = 935 kWh/sf for example.

To generalize:

SE * 70 yr + $CB * NatkWh / NatGDP < 10.2 kWh/sf.yr * 70 yr + $170/sf * NatkWh / NatGDP

where

SE = modeled net source energy for the project [kWh/sf.yr]   — about 10.2 kWh/sf.yr
$CB = project construction budget [$/sf]   — about $170 /sf, U.S.
NatkWh = National source energy use [kWh]  — about 29 trillion kWh, U.S.

NatGDP = National gross domestic product [$]   — about 19 trillion USD

This is mathematically equivalent to adding a penalty for high-budget construction and a credit for low-budget construction, which is in the equitable direction, on a world wide basis even. The emissions intensity of the Indonesian economy is actually higher than the U.S., I make it out to be 0.44 kgCO2e / USD, while the U.S. is 0.29 kgCO2e/USD. But they catch a break with the above scheme because their cost of construction is a lot lower, about $60/sf instead of $170 for the U.S., so multiply those two numbers together and the Indonesian building industry is putting out 0.44×60 = 26 kgCO2e/sf while the U.S. building industry puts out 0.29×170 = 49 kg/sf.

I switched to carbon accounting for a minute there, but I still prefer source energy accounting. It’s a pretty good proxy for emissions because 80% of the primary energy is coming from fossil fuel burning, but I like that source energy penalizes nuclear for being nonrenewable, whereas straight carbon accounting gives it almost a free pass.

Solving the above equation for Source Energy criterion:

SE < 10.2 kWh/sf + [($170/sf – $CB) / 70 yr] * NatkWh / NatGDP

This would also tend to do a favor for retrofit projects if they are able to save construction cost by reusing the structure — and that is the high-embodied-emission part, for concrete and steel buildings, from a materials point of view. The $170/sf could be generalized to a national average value as well, $NatCB. For residential projects, just substitute for the 10.2 as 3840 kWh/person * ResOcc / iCFA.

Probably only the operating-energy part of it tapers to zero in future. More emphasis can be put on initial-cost/embodied-energy savings by shortening the time frame. At 20 years instead of 70 they are about equal in the initial example. This would favor retrofits even more.

Many Cereals, One Cereal Aisle

GW

Graham Wright

The PHIUS+ standard has evolved on a very different path than the PHI standard, and they are in no way equivalent. That’s by design, based on deliberate decisions and building science, with a focus on cost-optimization and climate specificity. Still, confusion remains in some corners of the marketplace, confusion that is worsened by articles like the one that appeared in BuildingGreen a few weeks ago. (You can also read Chris McTaggart’s rebuttal at Building Green.)

Here, to provide a full accounting of how and why the standards are different, is PHIUS Senior Scientist Graham Wright. 

At the Seattle PHIUS annual conference in 2017, one of the keynote speakers, Doug Farr, came to a line in his speech saying “many boxes, one cereal.” The point he was making (as I heard it) was that there are a whole lot of “green” and “sustainable” and “high-performance” building programs, badges, and ratings all competing for attention or mind-share, and that this was not good because it made for a diffuse effort toward solving our sustainability problem. What you have, he said, is like a whole bunch of different cereal boxes on the shelf, but inside it’s “all kind of the same stuff.” It would be better if all these different outfits would get together to advocate with one voice.

While I agree that joining forces sounds like a good idea in general, personally I think he got the rest of it almost exactly backwards. For one of the other keynote speakers, Eric Werling, one of his major points was that the details matter. In terms of cereals, it is not all the same stuff — muesli is different from oatmeal or cornflakes or Cap’n Crunch®. We do not have many boxes — one cereal, rather we have many cereals, one cereal aisle. The bacon and hash browns are in another aisle. For the building industry the name of that aisle is probably “Green Building,” I think that’s the broadest and most recognizable term for what we’re talking about, and could encompass high-performance, sustainable, resilient, natural, living, green, healthy, net-zero, and of course, passive. Things it does not encompass but at most only overlaps with would be for example: secure, co-housing, modernist, Usonian, affordable, vernacular, brutalist, social, connected, low-tech and so on — these are quite different “programmatic” considerations and have their own aisles in the pan-galactic building store.

One of these things...

One of these things…

In the case of cereals the reason there are different kinds is because tastes differ, but also because values differ — if I value yumminess above all I will get Cap’n Crunch, but if I value avoiding the family curse of heart attack above all, I will get the oatmeal. In Green Building even more so, we have different programs because of differences in truly heartfelt values. Both builders and their clients bring different values to their meetings — if I am concerned about not polluting the environment, respecting brother salmon, I will go into natural building; if my children are prone to allergies I will look for healthy-home builders; if I

...is not like the other.

…is not like the other.

hate paying utility bills I will go for net-zero, and so on. So it is useful to have badges and rating systems corresponding to these different values or priorities, for matchmaking between builders and buyers of buildings.

Back to the common ground for a moment. It has dawned on many people I think that these different aspects of green building are connected, by a general crisis of climate and sustainability with industrial civilization, that we do have common ground in making the point that we must stop using fossil fuels and putting CO2 and other pollutants into the environment and doing so much mining, if we expect to also keep getting things like fish and wood and well water out of it at the same time, and that we might be able to form a chorus of voices calling for this.

I know of three such separate “common voice” efforts (heh) arising in the last couple of years:

PHIUS has joined Shift Zero, which has come together around the Architecture 2030 definition of zero net carbon buildings. Washington State already has one of the strictest state building energy codes, more stringent than IECC 2015, according to ACEEE, but at the initial Shift Zero summit meeting, the item “Roadmap to a Net Zero Building Code” was chosen as a major focus. This is relevant to us for two reasons: 1) We believe passive building should be on that road! The PHIUS vision statement is to “make high-performance passive building commonplace,” which it would be if it was Screen Shot 2019-08-27 at 1.46.00 PMcode. Also, 2) although it’s not spelled out in the short mission statement on the web site, the long version in the business plan speaks of the climate crisis and how passive building can both mitigate and adapt to climate change. We concur that as a society overall we must get to Zero, not just net-zero but Absolute Zero in terms of emissions, or 100% renewable energy to put it the other way. (The PHIUS Technical Committee has already taken this definition of Zero Net Carbon into consideration for our PHIUS+ 2018 standard update.)

Moreover, we are pursuing an ANSI-approved passive building standard, via the ASHRAE Standard Project Committee 227P. Participation in Shift Zero should allow us to both contribute to and be informed by a Shift Zero effort on Washington State code.

Our aim here is not to “get PHIUS written into WA code”, nor to “get an ANSI stamp” on PHIUS+ 2015 or even 2018, but to develop something that is both rigorous and more flexible, and of more enduring value. Our current standard is mostly performance-based, that is, based on modeled energy use. This requires modeling protocol, modeling software, and training in using it, for both project planners and verification/enforcement caseworkers. The vision for the ANSI/ASHRAE passive standard is that it would use a combination of prescriptive, performance, and outcome-based compliance paths to support the whole range of project scales – from small projects in backwater jurisdictions with few planning or enforcement resources to large projects in capitols that could take on custom cost-optimization studies. The value of PHIUS+ lies not only or even mainly in the current criteria but rather in the principles and methods underlying them, such as the priority on passive measures and conservation, the constrained cost-optimization for the heating and cooling criteria or the fair-share and national-solidarity principles for total energy use.

The “A” in both ASHRAE and ANSI stands for American. The ANSI mission statement is U.S. focused and the web page has a U.S. flag image. But the ASHRAE mission states pointedly that while they started out in U.S. they now have worldwide membership and global services, advancing sustainable technology for the built environment.

An ASHRAE passive building standard then, ought to be serviceable globally (at least in those parts of the globe that have building professionals.)

In my opinion PHIUS brings a track record of experience and care to this effort, as well as integrity, and humility.

As most of you will know, we started out practicing an “International standard” from PHI in Germany, applying it in the U.S. Our first major adaptation was in 2012 with the addition of greatly expanded quality assurance requirements from U.S. DOE programs. We found that the U.S. building industry simply needed a lot more guardrails on quality. This was in essence a cultural adaptation, as was our early support for the inch-pound unit system. Our second major change was a climateadaptation, in 2015 with the elaboration of the climate-specific criteria for heating and cooling.

To make a long story short, we found that the PHI heating and cooling criteria became disconnected from the principle of economic feasibility that supposedly underlay them, when applied to most climates in the U.S. and Canada, and we set out to redeem that promise. That disconnect affected both the heating and the cooling criteria in different ways, and was apparent in the data of PHI’s own climate parametric study of 20111. As a result of that study, PHI indeed adjusted their cooling criteria, adding to the (not climate specific) fixed base cooling demand a substantial and variable allowance for dehumidification (fair enough, there are not many passive measures that do this.) But the heating criteria still only made sense in one climate, and this was never fixed. Most of the U.S. being heating-dominated we thought that important and so went to work on it in 2013-14.

To make the story just a bit longer, what I would call the first-generation passive builders were splinter group off of the “passive solar” or “solar home” movement in the 1970s. Their differentiation was less mass-and-glass, less gain, more insulation, build light and tight. They tended to speak of “superinsulation” to differentiate themselves from the passive solar people, but passive building really is a better word for it; it’s not just about insulation. The canonical work summing up the first-generation ideas is The Superinsulated Home Book. Their concept of what counted as such a home was a little vague – they speak of reducing the heat losses until the building really starts to “act different” – but the definitional ideas included both low annual heating bills and low peak heating loads, that is, very small heating system capacity required, even to the point where a dedicated furnace was no longer needed; “just steal a little heat from the water heater.” This aspect I think forms the appeal to the heart of the “passive-house flavor” of green building cereal — the “self-heating building,” the “furnace-free house.”

The Superinsulated Home Book

The Superinsulated Home Book was published in the early 1980s, just as the bottom fell out of the solar movement stateside. The torch passed to Europe, and when PHI wrote their definition of a passive house, they focused on that low peak heat load concept and drew a line in the sand on how low it should be — basically, the point where the ventilation and heat distribution systems could be combined. This was reasonable and it does give a target number for design heat load, about 10 W per m2 of floor area, that would apply everywhere, at least in any heating-dominated climate. But when it came to writing certification criteria, an alternate compliance path was added by which one could meet a corresponding annual heating demand. Corresponding that is, in the climate of central Europe. This is the notorious 15 kWh/m2 or 4.75 kBtu/ft2, per year. If a building was designed to meet a peak of 10 W/m2 in central Europe, this is the resulting heating demand.

The problem, I say the glaring problem, is that that alternate criterion doesn’t correspond to the peak load definition in other climates. Again, this is according to PHI’s own study from 20111-2012. They took a study building, moved it around to a lot of different climates, adjusted the upgrades to meet the 10 W/m2 peak heat load definition, and plotted the resulting annual heat demand. It varied a lot, generally increasing as the annual average temperature got lower, but there was a lot of scatter, because annual temperature and peak load design temperature aren’t necessarily that closely related, it depends a lot on how close you are to the ocean.

Nevertheless, the PHI heating criteria remained the same two numbers for everywhere, either 10 W/m2 peak, corresponding to their definition, or 15 kW/m2.yr, which mostly doesn’t. Why? I have always darkly suspected that it is because in continental interior climates, the design temperatures for peak heating load are quite low, making the 10 W/m2 much the more difficult of the two numbers to meet. I think they could tell that it would be impractical for single-family dwellings, even attached like a townhouse end unit, to meet the ostensible definition, and so left the 15 kWh/m2 alternate in there as a close-enough cheat. I say it drives bad design, over-glazing, because solar gains do more to lower the annual heat demand than the peak load. (We showed evidence of this in our PHIUS+ 2015 development report published by NREL.)

Therefore, as I mentioned above, after a few years of applying PHI’s standard in the U.S., and noticing this lack of integrity with the heating criteria, we embarked on a reconsideration of the whole thing, in 2013-14. To my recollection, it just so happened that PHIUS and PHI both officially made standards announcements on the same day, March 15, 2015. PHIUS did make changes to all 3 “pillars” or marquee-level criteria — space conditioning, primary energy, and air-tightness. But, as evidenced by what got elaborated, it was clear that PHI had spent most of 2014 working on primary energy, the big change was the new and more nuanced Primary Energy Renewable (PER) metric, while PHIUS had spent most of that time working on new and more nuanced heating and cooling criteria. To go ahead and put a fine point on it, PHIUS took more care in 2014 with the core concept — the passive measures and how far to push them to drive down the heating and cooling loads.

(I must say it was irksome to get comments like, “sounds like PHIUS+ 2015 is just about bolting on some PV.’ when all we had done was put PV on the same footing as solar hot water, while PHI had spent the whole year working on renewable energy.)

Therefore, I think it is fair to say as a general matter, PHIUS has learned the importance of both “cultural” factors and climate factors to the development of passive building standards, and will bring this to an ANSI/ASHRAE standard development project. The approach to climate I think we have a fairly good handle on, and the multiple compliance options mentioned above should be able to accommodate various “building delivery processes”.

Lately it seems, we hear a lot of glossing over the differences between PHI and PHIUS. “It’s all good” kind of talk, “the differences are for nerds” and the like. At some level, this is fair enough. Yes we heart the furnace-free house, yes we like the EN/ISO 13790 monthly method for annual heating and cooling calculation and the EN 12831 for peak heating load, no we are not trying to be “lite” in general; honestly we get as much “we’re going with PHI because it’s easier” as the other way around.

But at some level the details do matter. In particular when it comes to talking about building energy code, mandatory, enforcement, permits approved or denied, people are going to want to know quite specifically what are the rules, yes?

Let’s think about the most simple and straightforward proposal I’ve heard for a building energy code: enacted in a skit by Henry Gifford and Chris Benedict of New York City, they propose the code consists of just a criterion on the design heating system capacity, that is, a peak heat load. Even with just that, you can see it would take some pages to spell out: by what method or methods of calculation? Do the methods vary for residential versus nonresidential buildings? Are solar gains or thermal mass to be credited with reducing peak loads? By what method are the design temperatures to be determined? Shall these be historical or forward-looking at climate change? Who is qualified to perform the load calculations and to review them? Does the criterion apply zone-by-zone or to the building as a whole? What if I have multiple buildings served by a central system?

So yes, at some level it is fair to say, PHI and PHIUS that is blueberry muesli, all good. But when it comes to the Food and Drug Administration, and to many customers, it is going to matter what is in those blueberries exactly. Are those real blueberries or fake f@#$% blueberries? Are the real blueberries GMO Roundup-ready blueberries or organic blueberries?

At PHIUS I think we have demonstrated some care and forethought in adapting our program and standards in the direction of suitability for incentives and codification in North America, while remaining faithful to the heart of the passive building concept. We will bring this experience and intention to the development of a more widely/globally applicable ANSI/ASHRAE Passive Building Design Standard With Path to Zero Emission or 100% Renewable Energy Society or the like.

ASHRAE requires a fairly public and transparent process and we seek the participation of the best building energy experts anywhere who find this vision agreeable — including PHI, with just one proviso: that 15 kWh/m2 everywhere is not going to make it, that is fake blueberry and we cannot have it in this muesli. If you can let that one thing go at last, the possibilities for fruitful collaboration open up. As those conveners I mentioned in Bonn, Seattle, and Portland have been suggesting, let us get the oars in the water and try to row in a more coordinated way at the goal of a Zero emission / 100% renewable built environment.

1 Schneiders, J.; Feist, F.; Schulz, T.; Krick, B.; Rongen, L.; Wirtz, R. (2012). Passive Houses for Different Climate Zones. Passive House Institute and University of Innsbruck.