What does PHIUS want?

[email]

Passive House is a poor name. At the end of the first Passive House training, we argued with Katrin about coming up with something better. She told us that the PHI insisted on it. Years later we're stuck with it. 

But the dumb name represented an exciting idea: extraordinary envelopes can do extraordinary things. Despite itself, Passive House came to mean the best buildings in the world. And despite PHIUS's negative PR campaign, Katrin tells us Passive House is growing exponentially.

After being let go as a Passive House certifier, PHIUS decided to start it's own standard, began arguing that Passive House is too hard for Americans, and told us that PHIUS+ would fix things with an easier standard. Now that they've finished, things look like this:

Passive House = heating your house with a hair dryer

PHIUS = running your house with PV

In other words, PHIUS isn't even playing the same game. So why do they insist on being a me-too version of Passive House? 

-Hayden

---

From: "Bronwyn Barry" <bronwyn...@gmail.com>
Sent: Tuesday, April 28, 2015 8:29 PM
To: "Scott Gibson" <scottg...@gmail.com>
Subject: Correction please!

Hi Scott,

As a GBA Prime subscriber, I'd like to respectfully request that you make a few corrections to your blog post in today's GBA article on the new PHIUS+ standards. While these PHIUS+ standards may have evolved out of the Passive House standard, they are no longer similar and therefore should not be referred to by the same name.  Using the German spelling of Passivhaus is also not correct. The Passive House Institute refers to all their projects in the global context using the english spelling.  They hold the trademark for the term 'Passive House Institute' here in the US, using the english spelling.

PHIUS has developed new standards that differ substantially from the Passive House standard. It is incorrect to state that the PHIUS+ standards qualify as 'new Passive House Rules.'  PHIUS themselves have noted that they are something entirely different.  Please do not conflate the two.

The Passive House standard remains strongly supported here in North America and that support base is growing. I'm happy to report that the Passive House standard will not be going away any time soon, but is itself evolving to include a very forward-thinking method of including renewable energy in its calculus.  (40,000+ buildings all working in various climates across the globe is a large number for you to dismiss so lightly!)

There are multiple organizations incorporated across the continent that are named 'Passive House (insert state/locale here)' who continue to support and promote the Passive House standard.  I am a proud founder of both Passive House California and the North American Passive House Network.  I would point out that PHIUS themselves have used the term 'passive building standards' to describe their new standards.  (Note lower case letters and elimination of the word 'house'.) 

There are many of us happily implementing and flying the flag of the Passive House standard here in North America. We're finding it works well in our various regions and are excited about the new directions it is taking with renewable energy.  Our businesses are being built around the Passive House name. We'd appreciate it if you reflected that in your reporting.

Many thanks for your efforts to accurately report on high performance building of all stripes.

With best regards,

Bronwyn Barry

AKA: @PassiveHouseBB

--

Bronwyn Barry, CPHD

Certified Passive House Consultant
Director - One Sky Homes

m: 415.819.7978

t: @passivehouseBB and @oneskyhomes

http://www.oneskyhomes.com/video/hair-dryer-home

     

www.oneskyhomes.com

Join me here at:      www.naphn15.canphi.ca 

[Adam Cohen]

Hayden,

I agree, Passive House is a terrible name in North America for sure!

I strongly disagree with the oversimplification that:

"Passive House = heating your house with a hair dryer

PHIUS = running your house with PV"

The reality is that PHIUS + is heating your house with a hair dryer in the climates it makes sense, but using another small heat source in the climates it does not.  In fact, from what I gather, in some climates the PHIUS + standard is tighter then PHI!  

It is also about recognizing the true PE factor of the North American Grid and the actual energy (over) usage of North Americans (as shameful as it is, every study shows this to be a fact when compared with our EU brethren and sistren)

It should be noted that PHIUS + is aiming at changing the narrative to  fair share of carbon per person in the existing non-renewable paradigm.

It should also be noted that the NEW PHI PER standard is about envisioning a 100% renewable grid, a very different (and exciting) development.

It does no good to throw stones and cause dissension in this small community.  I know you enough to know you understand the merits of both systems and really wish you would elect to take the higher road instead of stooping to oversimplification and mud slinging we see from others.  i believe you are above this.

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Certified Passivhaus Consultant - North America and Europe

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[Dan Whitmore]

Hayden-

 

For me, I see many of these difficulties stemming from the ambiguities of the label under which we are working to build 'the best buildings in the world'. For the most part, this open-ness has been utilized as a strength.

 

As Bronwyn states, there are 40,000+ Passive House structures in the world. Are 100% of these heated with the equivalent of a hair dryer? Clearly not. As only about 10% of them are even 'Certified' by some agency, how many are even designed/constructed to one of the handful of Passive House metrics?

 

Looking at those 40,000, how many are in jurisdictions which don't utilize the parameters of the Passivhaus Institute aka the Passive House Institute? I'd posit that there are a good percentage, yet they are included in the message that this is a successful building movement (which it is, thankfully). 

 

I find it disingenuous to say that the PHIUS+ Standard is not a Passive House Standard when there are many and changing definitions, even from your chosen authority. Yes, the parameters and defining metrics have been designated at differing touch-points, but they’re all built around this core idea: utilizing passive measures to reduce space conditioning needs by up to 90% and then using this terrifically effective strategy as a part of reducing total building energy needs by game changing levels. 

 

The ship of accepting a more open definition of ‘Passive House’ sailed from the European docks years ago. As I stated in an earlier post, ask the Belgians, Swedes, Norwegians, Finns, Swiss, and the Italians. Tossing out platitudes about how PHIUS is undermining the idea of Passive House and the numbers as defined by the entrusted German Scientists (I almost feel like they are being held up as the sacred Founding Fathers) is by design divisive. This resonates more as a protectionist move than an analysis of how to address energy consumption and build this movement as a whole.

 

To be clear, the basis of the recent Standard Adaptation is founded in both science and building practice and it is intended to move ‘the best buildings in the world’ further forward.

 

As a practitioner who is actively working on these structures, I can tell you fundamentally that both the ‘Passive House Classic’ and PHIUS+ Standards are terrifically difficult levels of efficiency to reach. The differences between them are nuanced and do need better definition; this will be forthcoming. They, with all the other Passive House paths, can actually affect how humans impact the globe especially when we work together. 

[Bronwyn Barry]

Dan, Adam et al,

I'm intrigued that you're now wanting to claim a piece of the Passive House pie after years of publicly bashing that standard and claiming it doesn't work here in our special climates.  I thought the story was that PHIUS+ is a big move away from the existing Passive House standard?  From all the articles PHIUS has posted, they're clearly claiming the more neutral territory of 'passive building standards.' And now you want 'Passive House' too? That's bold.  Furthermore, if PHIUS+ really is different and is calculated per person and includes credit for PV, why would you still want to call it 'Passive House?'  You can't have your pie and eat it too. (Adam, if you see that as 'mud-slinging' think of this as a creamy mud pie. :)

PHIUS+ wants to go it's own way and be its own thing.  Wonderful.  I'm happy to wish anyone who attempts to meet those standards the best of luck.  However, this insistence on claiming ground that is already occupied by a well supported, vibrant and existing standard is not only incredibly aggressive, but outrageously rude (particularly after the last three years of droning on about how 'Passive House' doesn't work.)  

This is no time to call in the Belgians, Swedes, Norwegians etc. to your defense either.  (We're not bringing in the Germans, the Austrians, the Brits, Kiwi's, Australians or the Chinese - even though they're all clamoring to attend and support our conference!)  Every single one of those variations (perhaps with the exception of one Italian) have remained well connected to the Passive House Institute.  Their metrics hew very closely to the original standard, with minor deviations or additions.  The PHIUS+ standards just moved far enough away from Passive House as to make claims to 'passive' tenuous, at best.  (A standard that hinges on the cost of and gives credit for PHIUS+PV tips the balance well into the realm of 'active'.)  And that is ok.

I can assure you that by differentiating yourselves clearly, embracing your 'active' side, and by finally letting go of the Passive House name, the possibility of 'working together' will become much more likely.  Nobody likes having their toes stood on. 

Respectfully yours,

Bronwyn

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[Adam Cohen]

Bronwyn,

You have obviously missed my post where I said it is a horrible name in North America and needs a new one (for all of us).  I personally am not claiming or not claiming anything.  I want to make several points about your continued over statements about my personal position. First, history:

1. In my career, I have always been out on the "crazy town" side of things, whether it was off grid "healthy homes" I built 30 years with no glues or chemicals utilizing 55 watt ARCO panels, or the SIPS projects I did starting in 1984 or the super insulated homes i built in the 80's that failed or the ICF projects in the early 1990s, or being an early Earthcraft & LEED proponent.  I have always looked for the best way to deliver great buildings.
2. Since 2009 Passivhaus has been the road I have traveled.  
3. In 2010, I had a very enlightening realization when Dr. Feist told me, "just go out and build good buildings, call them whatever you want"
4. Also in 2010, I spent a month in Germany and Austria investigating large scale commercial buildings and found that there were many buildings that were called Passive House that were far from it.  In fact, that theme has continued even on the tours that I have taken at conferences.  

Bronwyn, you keep trying to make my position equate with one of anti PHI and pro PHIUS, when in fact I am agnostic in the politics. Rather,  my engagement is in pushing the  high performance movement in North America forward, and i will use any and all tools to do it and help where and when I feel i can help.  If tomorrow someone came up with a better mousetrap to deliver market rate high performance i would adopt that. i would greatly appreciate it if you would keep your barbs aimed at the right spots.  If you want to discuss with me the pros and cons of different systems, then by all means let's do that, but fighting over a bad name is friggin' stupid and I do not and will not engage in it except to say it is a bad name for all of North America!  

You keep arguing (and in your position as keeper of the faith for PHI in the US, I understand this) that I am trying to claim the "name" when in fact i am not.  I am using the best of  anything I can.  in fact now I am running all my projects in parallel using both standards to fully understand their implications in the climates i work in.  You made the statement that I have been "publicly bashing that standard and claiming it doesn't work here in our special climates." I believe if you go back and look at all the things i have written and presented you will find that to be not true.  I have questioned many things about the standard, and intellectually that is what I do and have done my whole life.  I learned as a young person to question everything and ask why and ask myself "what do i think".  I believe you look at bringing up points like the "small house penalty" and the fact that in reality super cold climates only have 15 kWh/m2 conditioning budget when I get 30 kwh/m2 in my mixed climate" as bashing, when in reality it is having an informed dialogue.  I question everything and take nothing on FAITH on anything in my life, including energy modeling and metrics.

In the early days if i had not dug into the PHPP and uncovered the problems with the the 2007 versions cooling and dehumidification algorithms my projects would have suffered.  I never accept anything at face value until I understand it.

Even now, the PER system, which I think is very exciting, I want to know the intricacies behind the algorithms so i can understand it and ask myself "do i agree or do I see room for improvement" At this past conference I asked Wolfgang about this, remember this is who I am and what I do.

I hope that you will respect my intellectual curiosity and stop trying to portray my actions in the political way it feels like you are.  i believe you know me better then that.

Thank you!

[email]

Adam,

Thank you for your agnosticism. You are a wise man and I respect you. Hundreds have asked PHIUS to use its competitor's name. Keeping space between the Passive House and PHIUS allows for choice and fair competition. I think this benefits all of us.

Is it unreasonable to expect PHIUS to succeed on its own merits and distinguish its programs with a different name?

Yours,

Hayden

---

From: "Adam Cohen" <adam.c...@gmail.com>
Sent: Thursday, April 30, 2015 7:24 AM
To: Passive...@googlegroups.com
Subject: Re: What does PHIUS want?

[Adam Cohen]

Hayden, 

Once again I do not care what it is called, and I leave the naming to the people that have the authority to name it.  That is not you or I.

I always specify to my clients that I use Passivhaus methodologies (as well as other techniques) in my projects and that I will optimize their project for performance and cost. If the clients want a stamp of certification we will do that too, whether is  PHI, PHIUS+, LEED, Living Building, whatever they want. 

I believe those folks focused on the poor name are wasting effort and time and probably causing themselves more issues then the world as a whole.  Most folks (99% of North America) does not give a hoot about anything we are doing or what it is called.

I truly believe all your consternation about the poor name is "much ado about nothing" as the "market confusion" you speak of, in my experience does not exist regarding the name Passive House and PHI / PHIUS+, as much as it does that the Passive House name connotes 1970's over glazed, overly massive, uncomfortable Passive Solar Residential. This is the market confusion I deal with regularly.

~ Cheers!

[Joseph Giampietro]

Fellow members of Passive House Northwest and others interested in advancing high-performance buildings here in the Pacific NW and in other parts of the US:

The current conversation being open in the public arena is working against the general welfare of advancing any and all standards of passive house design and construction.  

I ask that you respectfully consider handling the more sensitive and nuanced discussions in a more direct and personal setting.

Thank you,

Joe Giampietro

NK Architects

[Bronwyn Barry]

Hey Joe et al,

While I understand that an open discussion board like this may be uncomfortable for those who shy away from active debate or confrontation, a forum like this is critical for democracy. (Don't worry, it's not too public - there are only 216 members, most of whom are really vested, like myself.)  These are very important issues for us all to discuss using our own names, businesses and sometimes organizations.  Democracy, by it's very nature, requires debaters and dissenters.

The burning questions here are around the naming:

1. Are the new PHIUS+ standards still 'passive' given that they allow credit for PV?
2. Why the attachment by PHIUS supporters to the name 'Passive House' if PHIUS+ is really a whole new calculus and independent standard?

As a community we all have a huge say in how Passive House and PHIUS+ are publicly presented and marketed.  I'm for not mixing them up or having the one attempt to dilute or subsume the other.  They're not the same.  Neither appear to be going away and no matter which methodology you favor, they are now distinct.  We all have the ability and obligation to respect these differences.  

Here's my suggested primer:

• Passive House Standard  = the international building standard defined by the Passive House Institute that has been widely adopted and used across North America and around the globe. Here in North America we have chosen to use the English spelling.  Most of our organizations and many businesses use this spelling.  (eg: Passive House Northwest, Passive House California, New York Passive House etc....)
  
• PHIUS+ Standards: these have recently been developed by PHIUS as a new certification offering.  The metrics, methods and software used to meet these standards are substantially different from the Passive House standard.  (This is stated repeatedly in all PHIUS publications on their standard.)  The PHIUS+ standards are an outgrowth of the Passive House standard, but they are now distinctly different animals.  

Not too hard to get straight.  Very important that we all are able to reach agreement on this.  What do you think?

Regards,

Bronwyn

[Adam Cohen]

In an effort to be technically correct I would like to CLARIFY Bronwyn's comments:

• PV is just one type of site generation.  In future discussions let's use the term site generation to be more technically correct.
• PHI's new PER standard will almost certainly require site generation on any certified project, unless the project goes to extreme conservation measures in reduction of conditioning.  (This is a good thing in my opinion)
• PHI's new PER standard allows for some SLIGHT (Hayden note the slight) reduction in conditioning energy if offset by site generation (once again a good thing in my opinion)
• PHIUS + Standard does not require site generation as part of the standard, but by making the per person metric a part of the standard, it is likely larger American homes with few bedrooms will most likely need site generation.
• PHIUS + Standard does not allow offset of the conditioning demand targets by site generation, they are separate.  It sets the heating and cooling demand and peaks that must be met, and sets the PE that must be met.  The PE can be helped with the portion of site generation that is used on site and not shipped to the grid, but does not allow for reduction of conditioning demand or peak loads.

I believe as always things are not as clear as stated, there are nuances and intricacies that must be considered.  My 2 cents is this, stop worrying about the word Passive - it is ridiculous, PHI allowing slight offset with site generation to conditioning demand certainly does not make it not Passive as the method clearly pushes passive measures first.  PHIUS + not allowing conditioning demand offset with site generation does not make it more Passive.

For both standards the use of Energy Recovery is considered in the "Passive" measures allowed when in reality Energy recovery the way it is currently implemented is not purely Passive on an orthodox interpretation.

If folks would like I would be happy to give a webinar on Passive Measures I prepared for the Ontario Association of Architects 2030 Challenge program.  In this presentation I discuss the definition on Passive and the spectrum on which the definition of the term can be built.

Arguing about a word is very silly.  

Understanding and implementing successful market rate high performance buildings is not.

[Bronwyn Barry]

Ahem. Here's the real info from the source:

Hi Bronwyn, 

PH stays PH with respect to the criteria for heating and cooling demand. This is really important! So no, it is not the heating demand that is flexible - only the total PER demand. Additional PV (or other renewable energy) can be used to offset the building's renewable primary energy (PER) demand. This is explicitly written in both the x-axis of the graph in the picture and in the description in red at the top. The heating demand is not included in the graph.

Thanks for pointing this out as potential misunderstanding - we'll have to make sure the communication and graphs are clear. Let me know if you have any ideas or suggestions. 

Kind regards, 
Jessica

-- 
Jessica Grove-Smith
Passive House Institute, Rheinstr. 44/46, 64283 Darmstadt, Germany
www.passivehouse.com

[Bronwyn Barry]

Peter, (if I use your logic I can call you anything and need not worry since "it's ridiculous" right?)

This is not just about a word, but a NAME.  (Try not be so dismissive about the name of a standard that many people have worked for two decades on.) 

I do agree that implementing successful market rate high performance buildings is the goal here. But as you've personally found, MARKETING them clearly is imperative. The same applies to building standards.  (Adam, your personal descriptor as the guy from 'crazy town' may not be helping you.)  The reality of the market place is that people want clarity, respectability, and something with a proven track record.  Cities and clients want to know what is what.  Mixing up two distinctive standards is a death-knell to both standards.

Passive House = heating your house with a hair dryer

PHIUS+ = powering your house with PV

I like Hayden's elevator pitch.  Perhaps the PHIUS supporters would like to improve the PHIUS+ descriptor?  Bring your best marketing guys and gals.  There's plenty of work for everyone, but only if we get this clear.

Bronwyn

On Fri, May 1, 2015 at 6:29 AM, Adam Cohen <adam.c...@gmail.com> wrote:

[Ryan Abendroth]

Longtime lurker here.. well maybe I have posted a few times.

The statement that: 

Passive House = heating your house with a hair dryer

PHIUS+ = powering your house with PV

Is an oversimplification of the actual real life and what it means on a building scale.  Let look at the following example for Seattle (its a NW group after all):

PHI criteria for Seattle Boeing Field vs PHIUS+ Criteria for Seattle Boeing field.

Annual Heating Demand         4.75                              5.1

Annual Cooling Demand         4.75                               1

Peak Heating Load                3.17                               3.4

Peak Cooling Load                none                              3.4

Primary Energy                     38.1                          varies per person

Primary Energy Factor         2.7 (or 2.6)                       3.16

Plug loads                             low                                high

I am going to use 2000 sq ft for simplicity. 

For system sizing, the peak load is 6340 btu/hr and 6800 btu/hr respectively. For me this is not a big difference and poses no threat to system sizing. Yes it means supply air heating through ventilation alone is no longer possible, though very few projects are actually doing that anyway.

For annual energy use, the Annual Heating Demand is 9500 kBTU's/yr and 10200 kBTU's/yr, which is equivalent to 2784 kwh/yr and 2989 kwh/yr. At $0.10 per kw (assuming electric resistance and much oversimplification), this is equivalent to $20.50 per year. Is it really worth fighting for and conserving that amount of extra energy if the marginal cost to get there is extremely high (note with efficient mechanical systems this number is even smaller)?  Even if you say "yes," I think we can all agree the difference for this specific climate is really small.

When translating that to other climates the PHI criteria are impossible to meet on the cooling side (heating can be met pretty much everywhere with the right mix of ingenuity and cash). I have been working on a project in central Florida, which recently determined that based on their current design (which was ok, but not great) it was not worth it to meet even the PHIUS+ criteria (set at 11.2 kBTU/ft2 for the annual cooling demand - combination of sensible and latent).  I also want to get out there and say, I don't believe that PHIUS+ has everything right (or that the PHI does either) they both have flaws when you start spreading it around to different climates and different building types.

Now on to the "finale." The assumption that PHIUS+ = PV. PV and all other forms of site generation can not offset any criteria besides Primary Energy. This is a necessary step because the combination of increased plug loads and lighting loads, along with the increase in the primary energy factor to 3.16 make it very difficult in every project that I have ran through the PHIUS+ numbers to meet the criteria for Primary Energy. Most of my projects using the best heat pumps on the market for both heating and hot water are ~10-15% above the primary energy criteria. This forces either natural gas or renewable energy in some form.

Also, please don't come after me on the math, I know it is oversimplified and that there are quite a few differences that I haven't accounted for, but hopefully it sheds some perspective on how much difference we are talking about when comparing the two standards.

Ryan Abendroth

[Bronwyn Barry]

Hi Ryan,

Welcome to the debate and thanks for your useful perspective.  Two things: 

1. Are you aware that the PHI Annual Cooling Demand criteria have been climate specific since the 2012 PHPP release?  Here's a sample chart from certifier, Tomas O'Leary, that includes the Miami, FL, numbers:
2. What would your suggestion/s be to modify the elevator pitch that Hayden has offered here:

Passive House = heating your house with a hair dryer

PHIUS+ = powering your house with PV

I look forward to reading your responses.

Bronwyn

[Skylar Swinford]

Bronwyn,

I'm currently working on the design of a PH project in Boise, Idaho, that will likely seek both PHIUS and PHI certifications. This project is meeting the annual heat demand requirement for PHI and PHIUS+ with no problems, but I've had to aggressively optimize the design to also meet the PHIUS+ peak load criteria. (PHIUS requires that their projects meet both the heat demand and peak load criteria.)

Because this project is aiming for PHIUS+, we've had to reduce the peak load instead of focusing on only annual heat demand. 

So in this case PHIUS+=smaller hair dryer and PHI=bigger hair dryer. This silly analogy, however, has gotten quite tired, and I don't like it. 

Simply repeating your silly analogy over and over won't make it any less foolish. This is not Fox News.  This poor horse that you have been beating died like 20 posts ago. 

Maybe someday we can start using this forum to share building science knowledge again. Instead of your religious ideology. 

Skylar 

--
Sent from my phone

[Gavin]

Here here.

I move that this conversation be respectfully moved to a new thread so this thread may renew the building science conversation this group used to produce.  I for one would happily subscribe to both.

Thank you Skylar and Joe.

Gt

Sent from my iPhone

[Adam Cohen]

Skylar, 

I am glad to hear you are running parallel project certs, I am doing the same thing. Very interesting, yes?

In the spirit of Gavin's comment I would like to make a proposal.  For those of us for whom the "dog in the race" is about better buildings delivered simply and affordably and not the silly, word, name whatever, here is my idea:

• Let's make a formal study period using a standard comparative rubric. 
• I have created a small comparison spreadsheet, others may have done the same thing (I would be surprised if folks have not)
• I will post my spreadsheet somewhere, others post theirs
• Then receive comments for a week or so about the standard format.
• We create a standardized comparative spreadsheet report to show points we want to compare between the two standards.
• We then run a year long standardized comparison of the standards in various climate zones we are all working in.
• We report back the information in the standardized format as we complete projects
• All the comparisons will be posted in an open forum for anyone to review.
• In a year, a committee compiles the results and presents the results at both conferences in 2016 for peer review.

What do folks think?  i am finding very interesting results already, as it seems Skylar is also.  so far, I am not finding that one standard is "easier", but rather different in interesting ways.

this way we stop the focus on how many names we can fit on the head of a pin and table this discussion for a year of data gathering.

If anyone wants to join me in this, i will be happy to coordinate the effort.

[Katy Hollbacher]

I second the motion. All in favor-?

Great idea, Adam!

————————————————————————————
Katy Hollbacher, P.E. - Beyond Efficiency Inc.
Certified Passive House Consultant, LEED Homes Rater, GreenPoint Rater
CA: 415.236.1333 x1 / WY: 307.200.7236 / beyondefficiency.us
*NOTE: Beyond Efficiency is closed Fridays

_____________________________
From: Adam Cohen <adam.c...@gmail.com>

Sent: Saturday, May 2, 2015 4:21 AM

Subject: Re: What does PHIUS want?

To: <passive...@googlegroups.com>

[BB Gmail]

Fair comments all. The study proposal sounds great. 

If it results in better clarity on the naming and marketing component that those of us doing public advocacy work for this movement need, I'm all for it. 

Bronwyn 

Sent from my iPhone

[Adam Cohen]

I have been thinking about this and would like volunteers to get rolling.

• Who has already done a comparison spreadsheet like me.  Please respond by Wed.
  
• Who would like to be on a committee to review the spreadsheets for format and standardized information - Please respond by Friday.

Lastly, this will be very interesting.  Especially when the 2009 english phpp comes out and we really get into the PER, alas but it will be a while

[Tad Everhart]

Hayden,

Thank you for raising important questions.  

And thanks to the others who contributed their views.

Almost as importantly, I want to thank Hayden for founding Passive House Northwest 5 years ago so that we'd have an independent, member-governed organization devoted to passive buildings where we can have these important discussions.    And thank Dan, Joe, Rob, and others who have helped sustain PHnw during those years.  And Bronwyn and Katy for our sister Passive House California.

Thanks also to the others who have contributed their points of view.  I learned a lot this afternoon. 

I valued Adam's comment about how small our community is.  We need each other to stand a chance at affecting the larger design and construction industries even if we don't agree on everything.  

I think it's worth the occasional elbow (even in public) to freely discuss important ideas with people who hold them passionately.  It clear to everyone involved (or looking in from the outside) that people speak their mind and ideas survive only on their merits.

The name and how we talk about competing standards is an important issue for me in my outreach.  I find that almost everyone from general public to residential builders to designers to government staff and officials want to know how to sort this out.  Just Tuesday the senior sustainability manager of a major city told me she wanted to sit down with me so she'd "understand the difference between passive house and passive house."

I'll do my best, but it's not easy.

In case it helps others, I've found that in getting started in this discussion with people, I first talk about passive buildings being the most energy-efficient buildings in the world.  Only then do I sometimes move on to introduce the Passive House Standard.  

Often , I don't get that far.  Too many times, I've had the same experience other related.  I'm so sick of people telling me they know all about it and immediately telling me all about passive solar buildings ala 1970s.

My elevator speech: Buildings meeting the Passive House Standard are the most energy-efficient buildings in the world.

Thanks, again, to all of you for your contributions.

Tad, Passivist    

[Andre Harrmann]

I've been following the discussion with interest, but have not done any comparison since I only work with projects following the international Passive House.
Since I wanted to dig deeper into PER anyways, I could help out by running some calculations in the already available German PHPP 9. I am also courious to see the spreadsheets and could provide review comments if needed.

André Harrmann  |  Dipl.-Ing.(FH), MHP, CPHD, LEED AP
Green Building Consultant  |  Harrmann Consulting
Director  |  Canadian Passive House Institute West (CanPHI-West)
Director  |  North American Passive House Network (NAPHN)
Project Manager  |  University of British Columbia (UBC)
web: 15kwh10w.com

    

...

[Hayden Robinson]

Hi Ryan,

 

PHIUS+ is not my forte, but no one else has jumped in, so I'll take a shot. I'm sure the crowd brain will correct me where I'm off.

 

My understanding is that you can't do the comparison that you are attempting without correcting for the differences in floor area metrics (TFA and iCFA), and internal-heat-gain assumptions.

 

In order to compare Passive House's TFA with PHIUS's iCFA, you have to add in interior partitions and doorways, stairs, a percentage of basements and store rooms, etc.

 

In the case of the Prospect Street Passive House, I found that, the conversion from TFA to iCFA was 150%. As Dan has point out, this number will vary from project to project. For a house with no stairs and no basement, the numbers would be closer. But, taking the Prospect St. House as an example, you would assume 2,000 s.f. for the Passive House version, and 3,000 s.f. for the PHIUS+ version. Alternatively, you could leave them both at 2,000 s.f., and make the correction in the PHIUS+ heating demand number: 5.1 x 1.5 = 7.65. In your example this bumps the PHIUS+ AHD to 15,300. Again, this is using Prospect St. as an example - other projects would be different.

 

An additional correction would be needed because PHIUS+ assumes a higher internal-heat-gain number that is typically more accurate for the U.S. Accuracy is good; however, for the purposes of your comparison, it adds free heat to the PHIUS+ scenario that is not present in the Passive House scenario. In order to compare the two standards, you need to add the same amount of free heat to the Passive House. This would reduce its AHD. I don't know what the PHIUS+ IHG numbers are, so I can't do this part for you, but the equation would be: Passive House AHD - (PHIUS+ IHG  x   iCFA) - (PH IHG x TFA). Or, at least I think so, but I'm getting tired. At any rate, you get the point.

 

-Hayden

 

From: Passive...@googlegroups.com [mailto:Passive...@googlegroups.com] On Behalf Of Ryan Abendroth
Sent: Friday, May 1, 2015 4:56 PM
To: Passive...@googlegroups.com
Subject: Re: What does PHIUS want?

 

Longtime lurker here.. well maybe I have posted a few times.

Bronwyn Barry, CPHD

www.oneskyhomes.com

 

Join me here at:      www.naphn15.canphi.ca 

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m: 415.819.7978

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Adam Cohen
Certified Passivhaus Consultant - North America and Europe

Registered Architect MD, VT, NH & CO, LEED AP, NAHB Green Professional

Design/Builder of the First US Passivhaus Public School Building

2012 VSBN Green Designer of the Year

2013 Green Builder Green Home of the Year

 

EMAIL POLICY

 

In an effort to increase productivity, I answer email as follows:

 

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540.312.8400 (cell)

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www.oneskyhomes.com

 

Join me here at:      www.naphn15.canphi.ca 

[Adam Cohen]

Hayden, Are you going to participate in the comparison study?  

[Hayden Robinson]

Me? I suspect the job is better left to those of you with high geek credentials. What is the goal of the study?

 

By the way, what is the conversion factor for PHIUS+ IHG to Passive House IHG? I confess, I don't even know what the Passive House IHG number is.

 

-Hayden

 

From: Passive...@googlegroups.com [mailto:Passive...@googlegroups.com] On Behalf Of Adam Cohen

Sent: Monday, May 4, 2015 4:20 AM
To: Passive...@googlegroups.com

[Dylan Lamar]

Adam and others,

I'm happy to support the effort. I haven't yet done any comparisons but have been meaning to do so.

I agree with others that market differentiation is important now that PHIUS has struck out on their own, and they are making quite an effort to re-brand the generic term to "Passive Buildings". But that will take some time. I don't appreciate the revisionist history written into the New York law journal article. It's sad to see Katrin show such disrespect to the very institution that gave birth to her (and my) life's work. But the fact remains that whether we're aligned toward PHIUS or toward PHI, we're stuck together in the same row boat. And we're tethered to a big ass freighter conveying coal toward our mutual doom. We've got to stop childish bickering, at times agree to disagree, and wake up to the bigger challenge that we need to work together to correct.

We need PHIUS to succeed. We need PHI to succeed. PHIUS has the political will and backing in the US. PHI has the technical depth that only comes from a team of 30+ physicists with good funding largely unbiased by corporate influence. These are tremendous gifts. I hope that PHIUS will be wise enough not to get their exclusive standard written into incentive programs. They should recognize that they need the expertise that comes with PHI and the PHI-aligned network in this country. I hope that the PHI-aligned folks will be wise enough to accept that PHIUS+ is here to stay, and that they are asking important questions about the direction Passive buildings should take in this country.

We have a lot of work to do. Let's not make it all that harder by fostering resentment. Maybe we could take a queue from Living Building Challenge folks and put more inspirational images of dandelions and flowers on our publications ;)

Dylan

[Adam Cohen]

hayden, the goal is to gather data on actual projects that go through design and certification to see how the different systems compare in reality

[Hayden Robinson]

Ryan,

 

Here is what I found for internal heat gains:

 

"Compared to PHPP calculations, the MEL/Lighting and internal heat gain increase incorporated here causes about a 1.5-2.0 kBtu/sf.yr reduction in modeled annual heat demand and increase in cooling demand. That is, the same building “would have” modeled with higher annual heat demand under PHPP assumptions."*

 

So, for this back-of-envelope comparison, this suggests we can add about 1.75 kBtu/sf to the PHIUS+ AHD. For comparison purposes, this yields a Passive-House-adjusted PHIUS+ AHD of

 

<(PHIUS+ Annual Heating Demand) x (TFA conversion factor)> + (delta Internal Heat Gain)

 

(5.1 x 1.5) + 1.75 = 9.4 kBtu/ft2yr

 

PHIUS Tech Committee:  am I getting this right? If I'm off track, somebody please correct me.

 

-Hayden

 

*(Wright , Klingenberg, Pettit:  Climate-Specific Passive Building Standards, p.31, Building America Report - 1405, March 2015)

[Adam Cohen]

Hayden, it is a bit more complex then that in real life.  

As heat demand is a proxy for energy use the number is irrelevant unless the effect on the site/source is considered concurrently with this number.  The other relevant number is the peak load and how that impacts equipment size.

This is the reason for a comparative study of actual projects.  

For example:  

• Regardless of the kWh/m2 or the TFA vs iCFA, the real question comes down to modeled energy performance and mechanical system sizing.  
• In the study I will be looking at many metrics but suffice it to say the bottom line that will give me personally the most insight into the comparison will be:
• Modeled total energy (site and primary with and without on site generation)
• Mechanical system size
• R-value comparisons 
• The reason for this is that both methods focus on interior comfort and interior air quality, (we can vigorously discuss whether peak vs annual is a better predictor of this) since both have similar guidance on lowest acceptable interior surface temperatures  and both methods also have similar guidance on fresh air exchange, to me this drops that discussion off the table.
• To me the site/source energy is a key comparison (the per sq m vs per person should produce very interesting data points).  

SO, i am not looking for a debate but rather to launch the comparative study period.  In the next few days I will be putting out some guidance for those that may be interested in participating.  i believe that this study will not "validate" one method vs another, but rather provide a comparative rubric for discussion.

[Hayden Robinson]

Thanks Adam,

 

You are right, there are a lot of other things going on. Also, I think we get back to the long vs. high-jumpers thing. If I've understood correctly, you are excited about total-building energy use - obviously an important and honorable focus. My principal interest is: enclosure performance. To me, as well as energy use, heating demand is a proxy for the quality of the building. I think it also says a lot about a building's resilience and dependability. As a bonus (while acknowledging  the contrary opinions of some on this forum) the academic literature suggests that efficiency measures may be a lot more effective than alternative generation, with respect to limiting CO2.

 

Of course, heating load is at least as good a measure of enclosure quality and resilience. In fact, it's an even better one. But my experience in the maritime Northwest suggests that peak heating events here are uncommon and  tend to occur when people are in bed and unconcerned about the room being cooler. Also, when peak loads are an issue, with a high-performance enclosure, they can be addressed with a very small amount of auxiliary heating. This has lead me to conclude that designing for peak load, though elegant, may be unnecessary. That said, I still have hope that passive technologies will evolve, beyond Passive House, to true no-power enclosures.

 

-Hayden

 

From: Passive...@googlegroups.com [mailto:Passive...@googlegroups.com] On Behalf Of Adam Cohen
Sent: Thursday, May 7, 2015 5:23 AM
To: Passive...@googlegroups.com
Subject: Re: Response to Ryan

 

Hayden, it is a bit more complex then that in real life.  

         

 

540.312.8400 (cell)

[Adam Cohen]

Hayden,

As I said the discussion about Demand vs Peak and comfort and energy use is one that can go on for a long time.  

Another interesting thing i just realized by your comments,  is that you are really focused in the PNW climate, I am working in climate zones 1-6 currently so my perspective and experience is a bit different when it comes to peak vs demand.

Also, I have not done a PNW project, but i have done other climate zone 4 projects and compared envelope requirements.  My experience is that in CZ 4, there is not a huge difference between PHIUS + and PHI envelope requirements to meet the heating and cooling demand and peak.

~ Cheers!

Web site: www.BuildSMARTna.com

Commercial Passivhaus information: http://passivscience.com/

Factory Built Passivhaus Component information: http://www.passivstructures.com/
Passivhaus information: http://www.passivehousedesign.us/

More Passivhaus info: http://www.viking-house.us/

High Performance Design: http://quantum-architects.com/

             

888.376.3424 (office)

540.312.8400 (cell)

[Hayden Robinson]

Since Adam is coming up with similar requirements for PHIUS+15 and Passive House in CZ4, maybe I'm missing something? For the Seattle CZ4 example, I came up with a PHIUS+15 AHD of about double that of Passive House (9.4 vs. 4.75 kBtu/ft2yr). Wouldn't a similar calculation for estimating peak heating load differences apply:

<(PHIUS+ Peak Heating Load) x (TFA conversion factor)> + (delta peak-load Internal Heat Gain)

= (3.4 BTU/ft2hr x 1.5) + delta IHG

= 5.1 BTU/ft2hr + delta IHG

 

I don't know the PHIUS+ peak-load IHG assumption (0.51 BTU/ft2hr for Passive House), but even ignoring that, PHIUS+ is about 160% of Passive House (5.1/3.2) for this example.

 

Moving it from Seattle to Blacksburg, VA (the place I lived in the other CZ4), I come up with a PHIUS+ heating demand of about 190% of Passive House (9.1/4.75):

 

<(PHIUS+ Annual Heating Demand) x (TFA conversion factor)> + (delta Internal Heat Gain)

= (4.9 x 1.5) + 1.75

= 9.1 kBtu/ft2yr

 

Similarly, I get a PHIUS+15 peak load of about 180% of Passive House (5.85/3.2):

 

PHIUS+ Peak Heating load

= (3.9 x 1.5) + delta peak IHG

= 5.85 BTU/ft2hr + delta peak IHG

 

Moving it to more challenging climates, PHIUS+15 and Passive House move further apart:

 

Coeur D'Alene, ID: 250% annual demand; 190% peak load

 

Kalispell, MT: 270% annual demand; 200% peak load

 

Grand Rapid, MN: 300% annual demand; 220% peak load

 

Anchorage, AK: 530% annual demand; 190% peak load

 

There is definitely a lot I don't know about PHIUS+15. Perhaps there is something about its peak load calculations that I'm not thinking about accurately?

             

 

888.376.3424 (office)

540.312.8400 (cell)

[Adam Cohen]

Hayden, et al,

I have almost finished the spreadsheet for creating comparison, then we can start to put in real projects with real numbers.  As i said before, I am very interested in three items:

1. peak loads or more specifically conditioning equipment
2. modeled site & source energy
   
3. Envelope R/U Values

I hope to have the information out this week.

[email]

Adam,

How are you correcting for the different internal heat gain assumptions of Passive House and PHIUS+?

-Hayden

---

From: "Adam Cohen" <adam.c...@gmail.com>
Sent: Tuesday, May 12, 2015 7:04 AM

[Adam Cohen]

There is no need for any "correction".  As you have pointed out, they are two similar yet different systems, so each system should be run with the systems standard assumptions. 

 When completed the real telling thing will be the results as i said before:

1. peak loads or more specifically conditioning equipment
2. modeled site & source energy
   
3. Envelope R/U Values

[Ryan Abendroth]

I think most of the points have been thoroughly discussed, but here are some comments anyway. 

I agree with Adam, that there are too many moving parts to use just a "correction" to determine. However, if a correction is used, Hayden is not that far off, though I would say in my experience, both the TFA to iCFA conversion factor and the IHG factors are higher than I have found in my experience, but even if you add a 1.25 multiplier (for iCFA) and 1.0 kBTU for IHGs there will be a much relaxed rate for heating demand (though cooling is going to get tougher, because those internal heat gains hurt).

The best comment Adam made was "My experience is that in CZ 4, there is not a huge difference between PHIUS+ and PHI envelope requirements to meet the heating and cooling demand and peak." This is a very important distinction. The target numbers may be different, but if the envelope R-values remain similar, the difference between the approaches may not be that large. Admittedly, I haven't done every comparison with my projects, but in the lower Midwest, we are talking about an inch or two of insulation difference (larger differences where its colder, probably no difference in hotter climates). Again, I don't have the magic answer because its much too nuanced for any type of absolute statement, but i do think its very important to look at the end results in addition to what the target is.

...

[Hayden Robinson]

I'm afraid you've lost me. I don't understand how comparing Passive House and PHIUS+ 15 versions of the same house, while assuming added internal gains for the PHIUS version, can generate meaningful results? Following PHIUS rules, the PHIUS house may also assume higher efficiency for the same HRV. In reality, internal gains and HRV efficiency will be the same in both houses.

 

Won't the comparison underestimate PHIUS+ heating demand? (Or overestimate Passive House demand, if you look at it from that perspective?)

 

-Hayden

 

From: Passive...@googlegroups.com [mailto:Passive...@googlegroups.com] On Behalf Of Adam Cohen
Sent: Wednesday, May 13, 2015 7:52 AM
To: Passive...@googlegroups.com
Subject: Re: Response to Ryan

 

There is no need for any "correction".  As you have pointed out, they are two similar yet different systems, so each system should be run with the systems standard assumptions. 

 

 When completed the real telling thing will be the results as i said before:

1.  peak loads or more specifically conditioning equipment

2.  modeled site & source energy

3.  Envelope R/U Values

 

-Hayden

             

 

888.376.3424 (office)

540.312.8400 (cell)

 

--

             

 

888.376.3424 (office)

540.312.8400 (cell)

[Hayden Robinson]

You're right Ryan. There's no uniform correction factor. My calculations looked at one example and was a back-of-envelope estimate. Other factors, such as higher PHIUS occupant-load and HRV-efficiency assumptions could also influence.

 

I think the take away is that, for the majority of heating-climate buildings, PHIUS+ 15 starts with a bigger demand number, multiplies it over a larger area, and assumes more internal gains. Peak load will tend to follow a similar pattern.  This suggests that, in cases where PHIUS+ and Passive House have similar demand numbers, there is something curious happening. 

 

But this brings me back to the long jumpers/high jumpers example. A goal of PHIUS+ is to be less expensive than Passive House.* Nothing wrong with that. The downside is expecting less performance for less money. Perhaps a fairer, more interesting comparison would be $/(kBtu/ft2yr).

 

-Hayden

 

* "It is too hard (expensive) to meet the (Passive House) standard in the colder climates. Relax there to increase adoption."

Graham S. Wright, Katrin Klingenberg, "Standard Adaptation: Upcoming changes to PHIUS+ Certification", slide 35, 8th Annual North American Passive House Conference, October 2013

 

From: Passive...@googlegroups.com [mailto:Passive...@googlegroups.com] On Behalf Of Ryan Abendroth
Sent: Wednesday, May 13, 2015 9:10 AM
To: Passive...@googlegroups.com
Subject: Re: Response to Ryan

 

I think most of the points have been thoroughly discussed, but here are some comments anyway. 

 

I agree with Adam, that there are too many moving parts to use just a "correction" to determine. However, if a correction is used, Hayden is not that far off, though I would say in my experience, both the TFA to iCFA conversion factor and the IHG factors are higher than I have found in my experience, but even if you add a 1.25 multiplier (for iCFA) and 1.0 kBTU for IHGs there will be a much relaxed rate for heating demand (though cooling is going to get tougher, because those internal heat gains hurt).

 

The best comment Adam made was "My experience is that in CZ 4, there is not a huge difference between PHIUS+ and PHI envelope requirements to meet the heating and cooling demand and peak." This is a very important distinction. The target numbers may be different, but if the envelope R-values remain similar, the difference between the approaches may not be that large. Admittedly, I haven't done every comparison with my projects, but in the lower Midwest, we are talking about an inch or two of insulation difference (larger differences where its colder, probably no difference in hotter climates). Again, I don't have the magic answer because its much too nuanced for any type of absolute statement, but i do think its very important to look at the end results in addition to what the target is.

On Wednesday, May 13, 2015 at 9:51:58 AM UTC-5, Adam wrote:

There is no need for any "correction".  As you have pointed out, they are two similar yet different systems, so each system should be run with the systems standard assumptions. 

 

 When completed the real telling thing will be the results as i said before:

1.  peak loads or more specifically conditioning equipment

2.  modeled site & source energy

3.  Envelope R/U Values

--

[Adam Cohen]

Hayden, you must understand that the demand calc uses this higher gain (more NA correct), but the peak calc still assumes the lower IHG since PEAK is used in system sizing conservative numbers are required.  The peak cooling is affected much more then the peak heating in PHIUS + compared to PHI, which as someone doing Mixed Climates is a good thing.  I have always used my own calculator for PEAK Cooling load, as the PHPP was not giving me what I knew to be a correct PEAK COOLING LOAD.

Hayden, I really think if you are running PHPP's you may want to compare since you seem to be interested

[Ryan Abendroth]

Hayden wrote: "A goal of PHIUS+ is to be less expensive than Passive House.* Nothing wrong with that. The downside is expecting less performance for less money. Perhaps a fairer, more interesting comparison would be $/(kBtu/ft2yr)."

On the face of it, all is true and very well was or may have been the intent. However, what I think we will find is not a lot of cost difference between the two at the end. It's still early, but based on projects I have been involved in, I think we will see minor envelope changes (that do cost less and are less complicated), but that those cost savings will be reinvested in mechanical and renewable energy systems. Whether that is pv, better heat recovery, more efficient hot water heating, waste water heat recovery and on down the line. This will be directly related to the fact that primary energy is hard to meet and in a lot of projects will be the controlling factor.  Less expensive envelope and lower envelope performance - probably (depends on climate). Less expensive building and lower building performance - unknown (but in many cases there is great potential for less overall energy use due to stringent PE requirements).

On Friday, May 15, 2015 at 9:37:31 AM UTC-5, Adam wrote:

Hayden, you must understand that the demand calc uses this higher gain (more NA correct), but the peak calc still assumes the lower IHG since PEAK is used in system sizing conservative numbers are required.  The peak cooling is affected much more then the peak heating in PHIUS + compared to PHI, which as someone doing Mixed Climates is a good thing.  I have always used my own calculator for PEAK Cooling load, as the PHPP was not giving me what I knew to be a correct PEAK COOLING LOAD.

Hayden, I really think if you are running PHPP's you may want to compare since you seem to be interested

On Fri, May 15, 2015 at 10:11 AM, Hayden Robinson <em...@haydenrobinson.com> wrote:

You're right Ryan. There's no uniform correction factor. My calculations looked at one example and was a back-of-envelope estimate. Other factors, such as higher PHIUS occupant-load and HRV-efficiency assumptions could also influence.

 

I think the take away is that, for the majority of heating-climate buildings, PHIUS+ 15 starts with a bigger demand number, multiplies it over a larger area, and assumes more internal gains. Peak load will tend to follow a similar pattern.  This suggests that, in cases where PHIUS+ and Passive House have similar demand numbers, there is something curious happening. 

 

But this brings me back to the long jumpers/high jumpers example. A goal of PHIUS+ is to be less expensive than Passive House.* Nothing wrong with that. The downside is expecting less performance for less money. Perhaps a fairer, more interesting comparison would be $/(kBtu/ft2yr).

 

-Hayden

 

* "It is too hard (expensive) to meet the (Passive House) standard in the colder climates. Relax there to increase adoption."

Graham S. Wright, Katrin Klingenberg, "Standard Adaptation: Upcoming changes to PHIUS+ Certification", slide 35, 8th Annual North American Passive House Conference, October 2013

 

...

[Hayden Robinson]

Adam,

 

If I understand you, for peak load, PHIUS+ uses the same per-square-foot internal-heat-gain assumption as Passive House - 0.51 BTU/ft2hr. This suggests that, since PHIUS+ and Passive House use different reference areas, a TFA correction factor is needed for the peak load comparison equation: delta peak-load IHG = 0.51 BTU/ft2hr x (TFA conversion factor - 1). Is this correct?

 

This would lead to the following equation for converting PHIUS+ peak heating load to Passive House:

                                                                            

<(PHIUS+ Peak Heating Load) x (TFA conversion factor)> + <0.51 BTU/ft2hr x (TFA conversion factor - 1)>

 

For my Seattle example, this produces:

= (3.4 BTU/ft2hr x 1.5) + <0.51 BTU/ft2hr x (1.5 - 1)> = 5.4 BTU/ft2hr

 This yields a PHIUS+ peak load of about 170% of Passive House (5.4/3.2), for this example.

Of course, all of this ignores potential differences in HRV-efficiency assumptions, which could push Passive House and PHIUS+ peak load requirements much further apart.

-Hayden

             

 

888.376.3424 (office)

540.312.8400 (cell)

--

[Adam Cohen]

Hayden, there are so many variables, that looking at one item in isolation skews the comparison.  One needs to look at the whole picture to get a really telling comparison.  Also, real projects (preferably ones being constructed or already done) will show me personally the most.

As I said earlier:

This is the reason for a comparative study of actual projects.  

For example:  

• Regardless of the kWh/m2 or the TFA vs iCFA, the real question comes down to modeled energy performance and mechanical system sizing.  
• In the study I will be looking at many metrics but suffice it to say the bottom line that will give me personally the most insight into the comparison will be:
• Modeled total energy (site and primary with and without on site generation)
• Mechanical system size
• R-value comparisons 
• The reason for this is that both methods focus on interior comfort and interior air quality, (we can vigorously discuss whether peak vs annual is a better predictor of this) since both have similar guidance on lowest acceptable interior surface temperatures  and both methods also have similar guidance on fresh air exchange, to me this drops that discussion off the table.
• To me the site/source energy is a key comparison (the per sq m vs per person should produce very interesting data points).  

SO, i am not looking for a debate but rather to launch the comparative study period.  In the next few days I will be putting out some guidance for those that may be interested in participating.  i believe that this study will not "validate" one method vs another, but rather provide a comparative rubric for discussion.

[Hayden Robinson]

Ryan,

 

As far as intent goes, PHIUS put it this way: "It is too hard (expensive) to meet the (Passive House) standard in the colder climates. Relax there to increase adoption."*

 

Regarding PE, for the example I'm looking at, PHIUS+ primary-energy requirements seem to have also been relaxed:

 

Passive House primary energy:

(11.14 kWh/ft2 per year) x (1,481 ft2) = 16,493 kWh/year

 

PHIUS+ primary energy:

(6,200 kwh/person per year) x (5 people) = 31,000 kWh/year

 

Of course, the comparison is complicated by other factors:

 

·        PHIUS's higher PE factor for electricity appears to make things more difficult for PHIUS+ projects, but it also encourages gas furnaces/boilers, water heaters, and clothes dryers which could remove most energy from the equation.

 

·        PHIUS's higher plug-load assumptions will make it harder on one hand, but the resulting added internal heat gains will bring down heating-demand related energy use.

 

·        PHIUS's greater HRV-efficiency assumptions may drop on-paper heating energy demand by 20%, compared to the same HRV looked at through a Passive-House lens.

 

Regardless, I think it would be a shame if, as you say, PHIUS+ builders end up spending less on enclosure improvements, and more on PV. To me, the dependability, resilience, and durability of enclosure systems are worth a lot. Also, the academic literature suggests that, compared to energy conservation strategies, alternative energy production may be ineffective at limiting CO2 emissions.

 

-Hayden

 

*Graham S. Wright, Katrin Klingenberg, "Standard Adaptation: Upcoming changes to PHIUS+ Certification", slide 35, 8th Annual North American Passive House Conference, October 2013

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