Climate Data and PHIUS+ 2015

 

Adam2smAdam Cohen is a principal at Passiv Science in Roanoke, Va, a PHIUS CPHC®, a PHIUS Builder Training instructor, the builder/developer of multiple successful passive building projects, and a member of the PHIUS Technical Committee. With the release of the PHIUS+ 2015 climate-specific standard, Adam weighs in on the importance of climate data sets.

Project teams have always needed to be discerning about climate data sets they use in energy modeling.  Whether it’s WUFI Passive, Energy Plus, PHPP or any other software, the old adage garbage in = garbage out applies. Project teams always must analyze and make a call as to how accurate the climate file is.

For example, I worked on a Houston, Texas project a number of years ago and there were several climate datasets that were close and one that was very different. As a team, we had to decide how to approach this in the most logical and reasoned way.

Recently as I analyzed a Michigan project, I determined that my two dataset choices were “just not feeling exactly right” so I asked PHIUS’ Lisa White and Graham Wright to generate a custom set. I can’t know that this one is exactly right, but I know that it’s as accurate and “right” as we can make it.

Note that when multiple data sets are candidates, it is not just altitude that matters, but location of weather station (roof, ground, behind a shed, etc.). Ryan Abendroth blogged on the subject of selecting data sets (and when to consider having a custom dataset generated) and I recommend you give his post a read.

Since PHIUS+ 2015 is a climate specific standard, it’s all the more important to use the best available.  We all know that bad data is not exclusive to PHIUS (remember the Seattle weather debacle in early versions of the PHPP).

It’s incumbent on project teams to use science, reason and judgment in interpreting climate data sets. Being on the water, in the middle of a field or in the tarmac of an airport makes a difference.

In New York City, for example, we have an oddity: There are three dataset location choices.

A satellite photo of NYC with Central Park outlined. The climate date for the Park is substantially different than that for other parts of the city.

A satellite photo of NYC with Central Park outlined.

One is Central Park, and the PHIUS+ 2015 targets for that are substantially different than the others. But, counter to a Tweet calling into question the validity of the PHIUS+ NYC target numbers, they are different because the Central Park climate data is substantially different – probably due to vegetation countering the urban heat island effect. It has a dramatic and pretty fascinating effect on the microclimate, and the U.S. DOE has a nice read on the subject.

For project teams lucky enough to have access to multiple data sets for their location, by rational comparison, they should be able to make an intelligent decision to use a canned set or to have a custom set generated.

It also more important than ever that the PHIUS+ certifiers to examine the weather data provided by a project teams to see if the project team made a logical, rather then an easy selection of climate data.

In addition, we on the PHIUS Technical Committee will continue to collect and monitor data and will tweak certification protocols as we see the need. But, I remind all my fellow CPHCs that bad climate data sets are endemic in the industry and it is important that project teams make careful decisions and that they reach out to PHIUS staff to help when climate data sets just don’t seem right.

Public Comment Opportunity: PHIUS+ Certification for Multifamily Performance Requirements (v2.0)

Chris McTaggart, PHIUS+ QA/QC Manager, wants your feedback…

Dear PHIUS/PHAUS community members,

Adoption of Passive House Institute US (PHIUS) PHIUS+ certification is growing rapidly. Of particular interest is the application of PHIUS+ certification for multifamily buildings. With several projects already certified or in the process of construction, and several more projects in the design phase, PHIUS expects certification of multifamily buildings to be one of the leading growth sectors for high performance, low-energy buildings moving forward.

With this in mind, PHIUS has created updated draft standards for certifying multifamily projects. These updated standards are intended to replace previous guidance offered by PHIUS for certifying multifamily projects. PHIUS is seeking review and comment from all vested stakeholders on these draft standards with the intent that a finalized version shall be released in Q2 2015.

The updated PHIUS+ Certification for Multifamily Performance Requirements (v2.0) contain several improvements to language regarding the specific performance modeling and testing expectations for certification of multifamily projects, including:

  • Modeled energy performance criteria
  • Infiltration testing requirements/protocol
  • HVAC testing/balancing requirements
  • Sampling protocol for dwelling unit-level testing/inspection
  • Additional onsite testing/inspection requirements

To create these draft guidelines, PHIUS solicited feedback from several constituents who are actively involved in the certification of high performance multifamily projects. These comments helped inform the standard development process, and the goal is that the most fundamental areas of need for clarification and formalization have been addressed.

Please take the time to read the attached PHIUS+ Certification for Multifamily Performance Requirements (v2.0) document below and make comments by June 8, 2015. Use the comments section below or email your input to certification@passivehouse.us

Thanks,

Chris McTaggart,  PHIUS+ QA/QC Manager

Feedback on the standard adaption: A summary

GWLast year the PHIUS Technical Committee published its draft report on a climate specific passive building standard. It also called for formal public comment. Here, with an update on that process, is PHIUS Senior Scientist Graham Wright.

We got some good feedback on our standard-adaptation work – fourteen folks submitted some fifty pages of formal commentary altogether. Thanks to all who took the time to write out their thoughts. The PHIUS Technical Committee (TC) reviewed all the feedback.

I’ll summarize the process, but first you might remember that our report is also a report to U.S. Department of Energy Building America (BA) program, a proposal for the next-generation Zero Energy Ready program (ZERH). The reviewers for BA sent 134 line-item comments on the draft report. (We’ve been busy responding to those, and we think the final report is much better now!)

Click on the cover graphic to download the final U.S. DOE Building America report at the Building Science Corporation site.

The DOE/BA and the passive house community have the same goals and are, at a broad conceptual level, working on the same thing (otherwise this work would not have been funded.)  At the workaday level though, there are a lot of differences, and also a lot of investment by the two communities in their own approaches – it’s part-and-parcel with the commitment and passion for better building that both communities share.  But when you ask the questions “is there anything passive house can bring to BA/ZERH” and “is there anything BA can bring to passive building,” it turns out the answer is yes.

The TC believes we’ve achieved a fruitful synthesis, a best-of-both-worlds combination. For example, when it comes to designing for high performance, we agree it’s better to set performance targets and do an energy design than to use prescriptive tables (and by the way that design can be somewhat site-specific). But when it comes to field quality assurance, then  a checklist table – like the BA approach — is the right tool for the job.

To put a finer point on it, we at PHIUS hope the final report persuades BA that the ZERH program should be a performance standard, with criteria on both heating/cooling loads and on total source energy, and that those performance targets are predicated on ducts inside, strict air-tightness, and using really good windows for comfort reasons.

Likewise we hope it makes the case to the passive building community that the heating/cooling criteria can be adjusted for economic feasibility / competitiveness in a climate-sensitive way, that the risks to comfort and building durability are low, and that the heating/cooling energy savings are still impressively deep.  Over all the climate locations studied, the proposed criteria represent median reductions in peak heat load of ~77%, annual heating of ~86%, peak cooling of ~69%, and annual cooling of ~46%.  (The baseline is 2009 IECC code.)

So, about those formal comments: Most commenters checked either 12-20 or 20+ years experience. In terms of survey questions we asked, no one liked star-ratings, so pass-fail it is. In going through the feedback the TC found no surprises–most all of the concerns had indeed been fully vetted en route a consensus over the past two+ years.  Here are some of the specific questions we received, along with answers:

Q: Could WP software be modified to make heating/cooling load calculations consistent with ACCA Manual J and ANSI/ASHRAE/ACCA Standard 183?
A: That is possible!  Added to the feature request list.

Q: Could PHIUS consider consolidating QA/QC checklist to be free standing from DOE ZERH and EPA Energy Star (for both residential and commercial projects)?
A: Some progress has been made on this. Stay tuned.

Q: Will the standard help me design smaller passive houses?
A: The short answer is probably yes.  There is no explicit “small house break” but there are three changes that indirectly tend to benefit small detached buildings at least in some climates:  air-tightness criterion by shell area instead of volume, source energy allowance per person instead of per square foot, and higher plug load defaults and detailed internal-gain accounting.

Q: Has there been any progress with PHIUS and NFRC in aligning data to meet PHIUS needs and possibly using NFRC data?
A: Not a lot. But we want to get it done this year. Third quarter.

Q: Please explain why you chose the specific denominators in the formulas. For example, why $ 0.155 electricity? 482 kWh? 1341 HDD65?
A: Those are the best-fit numbers determined by the regression analysis, that is, it’s like when you fit a line to a trend in x,y data, the trendline formula has the form y = m*x + b.  The numbers in the denominator are like the m, the slope or sensitivity to each of the factors.

In terms of final refinements to the new standard, PHIUS has been operating an alternate certification path along the lines of the BA draft report for some months as a pilot program. In the February and March meetings, the TC did pass some changes in advance of broader implementation. The changes came from both the feedback and the pilot program experience.

One kind of comment that spoke to us was, “this isn’t disruptive but you might want to change this to align with, or not conflict with, the building code.” The most to-the-point answer to feedback about rules is what gets changed or upheld, so here is the list of changes the TC agreed on:

  • Source energy: The U.S. source energy factor for electricity is adjusted to 3.16 (aligns with IECC 2015). The residential source energy limit is adjusted to 6200 kWh/person.yr.
  • Air-tightness criterion: 0.05 cfm50/sf of envelope area or 0.08 cfm75/sf (testing at 75 Pa aligns with commercial code and U.S. Army Corps). If testing at 75 Pa, report the flow coefficient and exponent from the blower door tests (that way the software can extrapolate to 50 Pa for compatibility of figuring the natural air change rate for infiltration losses).
  • Non-threatening air leakage: If the air-tightness criterion is missed, and the extra leakage can be proven to be due to a non-assembly-threatening leakage element such as a vent damper, certification staff may allow that element to be taped off for the purpose of passing the air-tightness criterion. The un-taped test result must be used for the energy model.
  • Phase-in period:  Dual certification path continues until September 15, after that the old protocol is phased out for PHIUS+ 2015.
  • Break-in period: If a project is seriously constrained on one of the criteria, a case-by-case overage may be allowed on any one of the four space conditioning criteria, or source energy, for the next year.
  • Retrofit:  The retrofit criteria are the same as new construction, except for a case-by-case energy allowance for foundation perimeter thermal bridges or other such hard-to-fix structural thermal bridges. Provided the design is “damage-free” that is, low risk from a moisture point of view.
  • Add-on badge: for supply air heating and cooling sufficient, per static calculation, with the average ventilation rate no more than 0.3-0.4 air changes per hour. (That is, low peak heating load and low peak cooling load. Special recognition for those who favor and design to this particular “functional definition” of a passive building.)

And finally, Katrin’s long-awaited favorite:

  • Add-on badge: for source net zero.  Onsite renewable electricity generation above any that was already credited as coincident-production-and-use, counts towards net zero with the same source energy factor multiplier for electricity, i.e., 3.16.

To me the most substantial comment was along the lines that cost has been added on to the building delivery process, when you consider the labor of the CPHC, the pre-certification review, and the rater visits for quality assurance. The TC believes much of this concern is simply a matter of getting used to the requirements until it becomes the new normal, but we know that there is room for improvement on making the planning tools easier to use, and we will keep working hard on that.  Most commenters felt it was also very important to get the standard written out in human-readable form, not just encoded in WUFI Passive, and we will work on this as well.

Overall, we believe that PHIUS+ 2015 will make passive building more cost-effective across climate zones. The community’s collective experience informed all the work–so thank you all for all your input and hard work and again, thanks to everyone who took the time to submit formal comment. We’re excited to implement the new standard and believe it will dramatically increase adoption of passive building.

 

From passive house to passive buildings–what’s new and how manufacturers are stepping it up

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Exciting times indeed for passive building in the United States: Passive design principles that originated here and in Canada are all grown up and making a furious comeback. Policy makers, researchers and scientists, builders and designers are all embracing passive building in their everyday practice.

And as always, the growth is evident here at NESEA’s annual high-performance tour de force: NESEA BE15. A quick recap: Passive Building Place–a concentration of passive building component exhibitors, and the tour of their offerings, is in its fourth consecutive year. For those who remember, we started my first blog on the NESEA trade show focusing on passive house products in 2012. Passive building was still tiny then compared to what it has grown into now.

PHIUS and its membership organization the Passive House Alliance US (PHAUS) – the leading passive building research institute and alliance in the US – is the anchor of Passive Building Place for the fourth straight year.

NESEA never stands still. In its topic selection for conference workshops and presentations it continues to ask the tough questions and pushes the boundaries. I am talking about the passive building standard adaptation work we have been doing on Tuesday in a half day workshop. On Wednesday afternoon as part of the core conference I’ll be presenting about very exciting multifamily developments specifically. The Passive Building Place has become a mainstay and is expanding every year with new manufacturers who have recognized that passive building will be a significant driver for high performing materials and components.

Larger projects like Orenco Orchards in Eugene, Ore.,  by CPHC® Dylan Lamar and GreenHammer are coming on strong–they need more manufacturers to step up to the multifamily and commercial passive building market.

But, as multifamily and commercial projects come on strong, we see hesitation amongst manufacturers regarding new components and material needed for larger building developments. This follows the past trend with single family passive homes: the architects and CPHC®s (Certified Passive House Consultants) have taken on the design of the first larger buildings find themselves ahead of the curve.

While this might sound glamorous to some, in practice it is quite a challenge for the teams. Architects are out to make ambitious reductions in energy and carbon with large buildings, and they need appropriate high performance components. In principle, much of what’s been learned and accomplished in single family applications is transferable. Ideally, however, manufacturers will develop turnkey and warranted solution packages for multifamily and other large buildings. What about superinsulated thermal bridge free airtight curtain wall systems? Is this too much to ask for?

Here’s a good place to start: At last year’s 9th Annual North American Passive House Conference in San Francisco, five leading multifamily passive building teams came together for a presentation.  The one component they all wanted was a fire-rated door, that complies with ADA requirements of a low threshold, is airtight and has exceptional thermal performance comparable to the passive house windows that have taken the BE Passive Building Place by storm over the past few years.

To see what’s cooking this year, we are back for another tour of the trade show with you! I will have the pleasure of guiding a tour on Wednesday, March 4 beginning at 5.30 pm just before the boat tour. We’ll be visiting exhibitors who offer products and components germane to the passive building community. We will stop at selected passive building place exhibitors and Passive House Alliance sponsors inside and outside Passive Building Place. Because there are so many it’s impossible to visit all–instead we’ll focus on innovations and a more in depth conversation of 5-10 minutes discussing the manufacturers’ products.

Also different this year:  We will take the investigative role and instead of highlighting the passive building products we’ve seen in past years, we will challenge vendors with a different question: What are you doing to support larger passive building developments? Are you seeing the effects from it in your practice and what are you doing to respond, to prepare for it? Are there new offerings in the pipeline? What are designers asking for, what is missing?

Our goal is to identify the gap so that we can fill it. We like to inspire manufacturers to take the growth in passive building seriously. Please join us on this tour to hear from manufacturers what they are hearing and to ask the right and tough questions to inspire more high performing systems development for larger U.S. passive buildings.

Twenty-four exhibitors are joining us this year in the Passive Building Place or elsewhere on the floor–they include sponsors of PHAUS, firms with PHIUS certified professionals on staff, firms offering PHIUS verified windows or doors, or that are collaborating with PHIUS/PHAUS otherwise. Those partners are listed here:

475 High Performance Building Supply (Booth # 759)

Auburndale Builders (Booth # 913)

Bright Build Home (Booth # 549)

Conservation Services Group (Booth # 709)

Fraunhofer CSE (Booth # 660)

H Window/Energate (Booth # 642)

Huber Engineered Woods (Booth # 743)

Klearwall Industries LLC (Booth # 862)

Intus Windows (Booth # 624) PHAUS Green Sponsor

Marvin & Integrity Windows (Booth # 939) PHAUS Silver Sponsor

Mitsubishi Electric (Booth # 707) PHAUS Silver Sponsor

New England Homes by Preferred Building Systems (Booth # 919)

Passive House Institute US/Passive House Alliance (Booth # 753)

Pinnacle Windows Solutions (Booth # 763)

PowerWise Systems (Booth # 814)

PROSOCO Inc. (Booth # 949) PHAUS Green Sponsor

Roxul (Booth # 860)

Schock (#636)

SIGA Cover, Inc. (Booth # 620)

Steven Winter Associates (#844)

Stiebel-Eltron Inc. (Booth # 749)

Yestermorrow Design/Build School (Booth # 1036)

Zehnder America, Inc. (Booth # 864) PHAUS Friend Sponsor

Zola Windows (Booth # 755) PHAUS Friend Sponsor

 

We won’t have time to stop at all passive building component vendors, but we urge you to stop check them all out as you find time. Make sure to stop by:

Dryvit (Booth # 430)

Enovative (Booth # 945)

European Architectural Supply (Booth # 727)

Fantech (Booth # 828)

Foard Panel (Booth # 830)

Green Fiber (Booth # 717)

Led Waves (Booth # 628)

Main Green Building Supply (Booth # 622)

Retrotec (Booth # 541)

Sanden International (# 563)

Schock USA (Booth # 636)

Tremco Barrier Solutions (Booth # 719)

Viessmann Manufacturing (Booth # 565)

Yaro DSI (Booth # 638)

Thank you all for participating in this and putting your weight behind this exciting emerging construction market. Again, you are true leaders in this market transformation towards high performance building products that is so needed to achieve zero/positive energy buildings through passive design. Thanks again for joining!

And have a great BE15!