NFRC Calculations Now Accepted for PHIUS Verified Window Performance Data Program

Graham S. Wright, Senior Scientist & Product Program Manager

window overview page image

 

PHIUS is pleased to announce the addition of a new path to performance data verification within our PHIUS Verified Window Performance Data Program. Based on the calculation standards of the US-based National Fenestration Rating Council (NFRC), this new compliance path offers an accurate and low-cost solution for manufacturers.

Previously in the PHIUS window program, window performance (U-value and solar heat gain coefficient) was only calculated based on European standards (EN/ ISO 10077-2 for frames/spacers, EN 673 for center-of-glass U-value, and EN 410 for solar heat gain.) Since the technical details of the EN standards differ from those of NFRC (which also have an ISO designation, ISO 15099), the performance numbers from the two methods could not be fairly compared. Although the technical sophistication of the EN and NFRC methods is similar, the actual NFRC labels give only whole-window properties for standard sizes and omit the component-level performance data needed by passive house modelers.

Now under the new program, domestic manufacturers who have already (or are currently pursuing) an NFRC rating can pursue this new calculation method in order to save time and money by avoiding additional calculation costs. The NFRC calculation method also allows performance numbers from North American products to be compared to those of European imports, thus giving passive house consultants and energy modelers performance numbers in a format that can be plugged directly into passive building modeling software WUFI Passive and the Passive House Planning Package (PHPP).

The “EN mode” of calculation will continue to be supported in the PHIUS window program. The EN method, referred to as “Orange Path”, is signified by an orange data label and noted in the border at the top of the label. As in the current program, pre-existing NFRC data files (for THERM and WINDOW) can serve as time-saving starting points for the EN-based calculations, but a significant amount of rework is needed due to the differences in method.

Orange Path data label, based on EN standards

Orange Path data label, based on EN standards

The label for the new “NFRC mode”, referred to as “Blue Path”, will have the same format and types of data listed as the EN mode label, but is signified by a blue data label. This path applies a conversion factor to the component-level data from the NFRC calculations.

Blue Path data label, based on NFRC standards

Blue Path data label, based on NFRC standards

PHIUS and NFRC jointly developed a program to train qualified NFRC simulators to run the proper conversion to produce the Blue Path data labels as an extension of their regular work on NFRC ratings. The conversion has two aspects – adjusting for the difference in standard window sizes, and for the different treatment of the extra heat loss at the edge of the glass due to the spacers. More details about the glass-edge translation can be found in a 2014 report entitled “NFRC and PHIUS U-factor Calculation Comparison” by Jeff Baker of WESTLab and NFRC. Verified product performance values are then provided to PHIUS by the NFRC modeler and published to the PHIUS Verified Window Performance Database.

PHIUS calculates the center-of-glass properties in a climate-dependent way, rather than using fixed environmental conditions, and incorporates climate-dependent recommendations on the data label. Since higher performance is required to get recommendations in more extreme climates, this provides “bragging rights” for manufacturers in addition to providing numbers for comparison-shopping and numbers for energy modeling.

For more information and to download the Program Overview and Program Application & Instructions in PDF, visit the PHIUS Verified Window Performance Data Program site. Find a qualified NFRC simulator here and submit your product for data verification today.

If you have any questions, please contact Graham Wright, Senior Scientist and Product Program Manager, at graham@passivehouse.us.

From Twin Countries to Twin Cities: China is Making Strides in Bringing Passive Building Mainstream

Katrin Klingenberg, PHIUS Executive Director

 

Passive House Alliance China’s 3rd China Passive Building Summit in Shanghai was followed up by a one-day expert meeting and workshop. The group rode out together to old town Shanghai, a nice area of the city consisting of mostly low-rise buildings. The fall weather had now finally turned a little nippy and drizzlier than the days before, and I was happy to have worn my jacket that day. Shanghai is unique: for two months out of the year (one each in the spring and fall), the temperatures are on the cool side, requiring no cooling and almost no heating, but the humidity is still too high to be comfortable.

The workshop was organized by Passive House Alliance China and took place onsite at a high-performance multifamily retrofit project located in a high-end gated community. Upon our arrival we were welcomed into a beautifully designed lobby where refreshments were being served to the invited stakeholders representing the construction industry and building science field from different cities in China. Following lunch, we had the opportunity to tour several of the completed high-performance apartments and begin to delve deeper into high-performance construction methods in mixed/humid climates with a focus on the cities in the Yangtze Delta. The main focus was on large-scale multifamily buildings, a rather typical and ubiquitous building typology throughout China.

If China and the US are country climate twins, then Shanghai is a close twin to Houston’s southeast Texas climate with the exception that Shanghai gets a little bit more rainfall. The most important challenges for passive design space conditioning solutions in these cities are not the thermal loads – it’s the humidity! Thermal loads are easily reduced to very low peaks by using passive design strategies such as moderate amounts of insulation (4 inches of mineral wool for a larger scale buildings will suffice), balanced ventilation with very good energy recovery efficiencies, excellent windows (double pane with thermally-broken frames), and passive level airtightness. But the high humidity load from ventilation during summer and the shoulder seasons can only be reduced so far. A significant dehumidification load remains, often during seasons when little or no cooling is required, as was the case while we were in China.

Improvements to the building envelope to minimize heating and cooling peaks also effects the ratio of sensible to latent cooling loads – resulting in the latent load becoming equal to or larger than the sensible load. While in less efficient buildings the sensible load far exceeds the latent load and can be taken care of by traditional cooling equipment, in highly efficient passive buildings it is the latent load that is now equal to or even dominant (see examples from Beijing and Hong Kong in the graphs below). This poses a new challenge for low-load comfort systems.

sensible-heat-ratio

The graphs illustrate how the sensible heat ratio decreases if the building envelope is improved for the climates of Beijing and Hong Kong. (slide credit: Hartwig Kuenzel, Fraunhofer IBP, NAPHC2015 keynote)

Climate specific targets also matter a great deal in this climate. In mixed climates, the right balance between heating and cooling targets becomes critical to avoid over-insulation and overheating risks. Window performance in mixed/humid climates needs to strike the right balance as well in order to not inadvertently increase cooling loads. Windows need to be optimized for both cases, heating and cooling, to perform at their best. In the climate of Shanghai as mentioned previously, good double pane windows with a lower solar heat gain coefficient and thermally broken frames are typically the right choice to meet comfort targets and to avoid contributing to overheating. Accurate assessment of internal gains must take into account culture, lifestyle, occupancy, and other factors as they have a significant impact on the overall energy balance of high-performance passive buildings.

In the case of China for example, cooking plays a major role in the vibrant Chinese lifestyle and culture, as we were lucky enough to experience first hand as our gracious hosts showed us the best and most interesting dining spots around Shanghai. Food is central to the culture and if folks are cooking a lot of flavorful and spiced foods in their homes in a climate with significant cooling loads, they will want directly vented kitchen exhaust hoods! Grease, odors, and heat need to get captured and thrown out right at the source. I was impressed to see a novel solution to this problem as we toured the retrofitted apartments. Each unit had two kitchens: one being the “real kitchen” with the big stove, prep area, and fridges which were separated from the main living space by sliding doors to minimize the negative indoor air impacts on the rest of the apartment, and the other one adjacent was an open kitchen concept with a bar for entertaining! What a brilliant idea (if you can afford it)!

Now, what about energy modeling? We have often said that more complex climates really should be modeled using dynamic whole building energy balancing tools such as WUFI Plus. What makes the climate more “complex”? Cooling and dehumidification is needed when the exterior temperature gets closer to the interior comfort zone and begins to fluctuate around it. The warm season is dominated by diurnally reversing heat and moisture flows – in during the cooler nighttime, and out during warmer daytime temperatures. Add moisture into this back and forth and it becomes really complex. To be able to accurately predict how components and the whole building will perform from an energy and hygrothermal perspective, the designer really needs to perform a dynamic whole-building energy model based on hourly data to make the right choices. In contrast, in a heating dominated climate, exterior temperatures are swinging far enough away from the interior thermal comfort zone so that heat and moisture flows are mostly flowing out. Static models are accurate enough for simpler climates such as this.

The graphs illustrate conditions for both heating and cooling/mixed climates. The static monthly balance method as employed by WUFI Passive is sufficiently accurate to predict energy use in a heating dominated climate. In cooling/mixed climates such as Shanghai and Houston, dynamic whole-building energy simulation (WUFI Plus) is recommended. (slide credit: Hartwig Kuenzel, Fraunhofer IBP, NAPHC2015 keynote)

The graphs illustrate conditions for both heating and cooling/mixed climates. The static monthly balance method as employed by WUFI Passive is sufficiently accurate to predict energy use in a heating dominated climate. In cooling/mixed climates such as Shanghai and Houston, dynamic whole-building energy simulation (WUFI Plus) is recommended. (slide credit: Hartwig Kuenzel, Fraunhofer IBP, NAPHC2015 keynote)

Hygrothermal wall performance checks should be best practice for passive designs in mixed/humid climates to avoid any kind of condensation risk. As China ramps up their energy efficiency efforts in varying climates to near passive building levels and experiments with materials it will be critical that these models are created as project teams might not be familiar with just yet or have no long term experience with this risk management in mixed/humid climates, which can lead to critical and significant failures.

Now, what about the high-performance apartment tour, where are the Chinese at with their high-performance solutions today?

I was thoroughly impressed with what they had already in place in terms of execution, performance, details, mechanical solutions, and – to top it all off – a standardized monitoring interface centrally located in the home providing constant feedback on thermal comfort and indoor air quality to the home owner including fine particulate matter (PM 2.5) and inside to outside air quality comparisons. In Shanghai it is often the case that outdoor conditions are worse than indoors due to high pollution levels.

The project we toured was a retrofitted five-story brick building that had been upgraded by adding a 4-inch layer of mineral wool exterior insulation, airtight layer, and a new clay tile façade. The reported tested air-tightness result was 1.5 ACH, which is very respectable for a retrofit! Space conditioning was solved in a very elegant and most comfortable way: a separate energy recovery balanced ventilation system with appropriate filtration and dedicated integrated dehumidification took care of controlling ventilation humidity loads and outdoor pollutants (as evidenced on the screen of the monitoring interface in the living room, see opening photo). Space conditioning was handled by a separate point source solution consisting of hydronic heating and cooling integrated into the room’s ceiling. Radiant heating and cooling is a more costly, yet very comfortable high-end solution. Controlled infiltration and humidity loads are key to this solution to avoid condensation. So is awareness by the homeowner. They need to be put on notice that they can’t cool the home and leave the beautiful lift and slide high-performance balcony door open at the same time!

The developer reported that the passive house approach works financially for them for the high-end market. As you might expect, two bedroom apartments were selling in the millions, as would be the case for similar real estate in any other cosmopolitan global city.

Can passive go mainstream in China?

If I may offer my personal prediction: the Chinese have taken a surprising global lead in fighting climate change and have identified aggressive conservation goals for buildings as a valid strategy. The government has passed mandates to local jurisdictions to find appropriate cost effective solutions. If China addresses the cost optimization of passive building measures based on varying climates, construction paradigms, and energy costs in China similarly to what PHIUS did in the US, then they should certainly be able to generate design guidelines aimed at presenting the most economical path to zero. At the rate that they are going, I believe China will bring passive building to the mainstream before he US does because they have the political will, effective materials and components, knowledge of building science and energy modeling, and cost effectiveness strategies to get there.

What about the state of typical mainstream construction in China?

From what we saw, most apartments in Shanghai already have their own air-to-air heating and cooling heat pump unit sitting on their balcony. Pair that common solution with good airtightness, balanced energy recovery with dedicated dehumidification, moderate amounts of insulation and appropriate hygrothermal wall design, good windows, and you are there.

It would be great to see China taking the lead!

 

– Katrin

Transitioning from PHIUS+ to the PHIUS+ 2015 Passive Building Standard

Lisa White, PHIUS Certification Manager

 

Lisa White, PHIUS Certification Manager

Lisa White, PHIUS Certification Manager

Certification Update: PHIUS will not accept PHPP v9 for PHIUS+ 2015 Project Certification

Up until now, Passive House Institute US (PHIUS) has allowed project teams pursuing PHIUS+ Certification to use one of two passive house modeling tools to model their projects: 1) WUFI® Passive, the passive building modeling software developed by Fraunhofer IBP in collaboration with PHIUS and Owens Corning, and 2) Passive House Planning Package (PHPP), the passive house modeling tool developed by the Passivhaus Institut (PHI). However going forward PHIUS will not be accepting the latest version of PHPP v9 for PHIUS+ 2015 project certification.

Since the release of the PHIUS+ 2015 Passive Building Standard in March of 2015, PHIUS’ standard now differs significantly from the PHI standard. Specifically, the PHIUS+ 2015 Standard uses climate-specific targets for space conditioning energy use (the first such passive building standard to do so), limits overall energy use for residential buildings on a per person basis (rather than a square footage basis), and now uses a different metric for air infiltration.

For the first six months after the PHIUS+ 2015 Standard went live, project teams could elect to pursue either the earlier PHIUS+ Standard or the new PHIUS+ 2015 Standard. All new projects registered after September of 2015 are required to pursue certification under the PHIUS+ 2015 Standard.

 

Modeling Tools for Certification

Since the release of WUFI Passive in 2012, PHIUS has stopped teaching PHPP software during Certified Passive House Consultant (CPHC®) training and began exclusively teaching passive building energy modeling with WUFI Passive. PHIUS has since trained over 1,100 building professionals in the WUFI Passive software to date. In conjunction with the release of the PHIUS+ 2015 Standard, Fraunhofer released WUFI Passive v3.0, which includes a “PHIUS+ 2015 mode”. This software is uniquely suited to PHIUS+ 2015 projects, the North American passive building market, and is available for free on the Fraunhofer website.

Previously, project teams could use either WUFI Passive or PHPP for PHIUS+ project certification, and PHIUS continued to accept both modeling tools even after the release of the PHIUS+ 2015 standard. However, this was not without extra effort from the PHIUS project reviewers, as each PHPP submitted for PHIUS+ 2015 certification required a bit of “jury-rigging” in order to verify compliance with the PHIUS+ 2015 Standard. This adds time, and likely an extra layer of confusion, to the certification process.

In October 2015, the PHI released PHPP v9[1]. While this new software offers a variety of updates and new calculation protocols, PHIUS feels this software is no longer appropriate to verify compliance with the PHIUS+ 2015 Standard. As these two passive building standards diverge, the verification software also suitably continues to diverge. This ultimately does not come down to which software is “better”, but rather is simply about which software tool is most appropriate for each standard.

PHIUS will continue to accept earlier versions of PHPP for PHIUS+ 2015 certification, from the “06-02-10” IP overlay of the 2007 PHPP up through PHPPv8.5, but will not accept PHPP v9 for PHIUS+2015 certification. Eventually PHIUS will only be accepting WUFI Passive for modeling of PHIUS+ 2015 projects, but the date for this has not yet been determined.

For project teams with completed PHPPs that would like to transition over to WUFI WUFI logoPassive, PHIUS is offering a new service for a “one-time conversion” of your project from PHPP to WUFI Passive. The flat fee of $1000 for this service also includes the creation of a SketchUp file for the building and a walk-through of the completed model with PHIUS Certification staff. Contact certification@passivehouse.us for more information.

If you are a CPHC who has been meaning to venture into the world of WUFI Passive, PHIUS offers WUFI Passive training programs at various locations throughout the year to help get you up to speed on creating your own models in the software. Visit the WUFI Passive Training page for more information and to register for upcoming trainings.

Lastly, keep in mind that modeling tools are a small (albeit integral) part of the big picture. Try not to lose sight of the overall goal, which is to build energy efficient and resilient buildings that help to reduce the carbon footprint of the built environment. Regardless of your program preference, every step toward these goals is a step in the right direction.

 

[1] PHI allows project teams to pursue certification under previous iterations of their passive house standard as well as earlier versions of PHPP. However PHI’s new PER metric (the PE metric was used previously) requires using PHPP v9, the only version of the software able to calculate this. Thus PHPP v9 is not yet required for all projects; a sunset date for older versions of the standard and software has not yet been determined. For more information, see the “Criteria for the Passive House, EnerPHit and PHI Low Energy Building Standard” document on PHI’s website.

 

 

About WUFI Passive 

WUFI Passive is a powerful modeling program that dramatically improves the quality and efficiency of the passive building design process for Certified Passive House Consultants (CPHC®). The software allows for calculation of both static passive building energy modeling, as well as dynamic energy modeling for comfort and hygrothermal analysis. The user-friendly interface allows for SketchUp & Revit import, incorporates a seamless toggle between SI-IP, and generates high quality results reports for communication with clients and the PHIUS Certification team. Learn more at the WUFI website.

 

About the PHIUS+ 2015 Passive Building Standard 

Developed in cooperation with Building Science Corporation under a US Department of Energy grant, the PHIUS+ 2015 Passive Building Standard is the first and only passive building standard based upon climate-specific comfort and performance criteria aimed at presenting an affordable solution to achieving the most durable, resilient, energy-efficient building possible for a specific location. PHIUS+ 2015 is also the only passive building standard on the market that requires onsite QA/QC for certification.

Buildings designed and built to the PHIUS standard consume 86% less energy for heating and 46% less energy for cooling (depending on climate zone and building type) when compared to a code-compliant building (International Energy Conservation Code IECC 2009), resulting in an overall site Energy Use Intensity (EUI) of approximately 10-20 kBTU/ft2 year.

10th Annual NAPHC – best party of the year, maybe ever…

Wow – was that a successful conference! It has been a week and I am still processing it all. Chicago was unlike any other conference — things did not slow down in the office after it was all over, they rather accelerated. It indeed appears we have reached a tipping point.

From more than one person I heard that it seemed that the quality of work, detailing expertise and technical knowledge, size of projects and complexity of building types had reached a new high. And, compared to the early years, we were not just talking theory and intentions—but what people had done! Really impressive.

LEFT: Dr. Hartwig Künzel giving the Day 2 Keynote -- RIGHT: Sebastian Moreno-Vacca participating in the Architects' Hootenanny (L-R: T.McDonlad, T.Smith, J.Moskovitz, Sebastian, ?)

LEFT: Dr. Hartwig Künzel giving the Day 2 Keynote — RIGHT: Sebastian Moreno-Vacca participating in the Architects’ Hootenanny including (l-r): T.McDonald, T.Smith, J.Moskovitz, Sebastian, C.Hawbecker)

New modeling tools such as WUFI Passive (Technical keynote Hartwig Künzel, day two) are making building science interrelationships more visible and intuitively understandable. WUFI Passive is enabling CPHCs to optimize designs using “hygrothermal mass” (ever heard of that?) to optimize humidity loads and even to inform design decisions overall (as Sebastian Moreno-Vacca illustrated in his session) to create a unique architectural language! How cool is that! Science, heat fluxes and thermal dynamics begin to shape architectural form.

Dirk Lohan, Principal, Lohan Anderson -- Welcomes conference attendees to Chicago

Dirk Lohan, Principal, Lohan Anderson — Welcomes conference attendees to Chicago

Dirk Lohan—Mies Vander Rohe’s grandson, and an extremely accomplished architect in his own right—hinted at this development during his welcoming remarks.

“I believe that we will begin to see as beautiful what also is energy-conscious,” said Lohan.

Supported by the John D. and Catherine T. MacArthur Foundation

But maybe the most significant news is the explosive development in the multifamily affordable housing sector. It is seeing significant growth, interest and pilot developments going up in many places of the country. Thanks to the support from the John D. and Catherine T. MacArthur Foundation, we were able to make this our core topic for the conference and will be able to actively provide support to the affordable development community.

The pre-conference sessions included a daylong affordable housing Hootenanny that brought together successful affordable, multifamily housing project teams together who generously shared lessons learned and experience. Four different project teams presented during an intense full day. The morning and afternoon presentations drew full rooms of affordable housing developers who soaked up the information and had terrific, incisive questions

The same teams presented again during the core conference breakouts in a more condensed form for those who were unable to attend the hootenanny. In addition, there were more presentations on even bigger size affordable projects in progress:

  • A 101 unit affordable development in New York now under construction in the Rockaways (Steve Bluestone, Bluestone Org.)
  • A planned affordable retrofit of a 24 story historical brick building in Chicago (Doug Farr, Tony Holub from Farr and Assoc.), the Lawson House.
  • 24 story residence hall under construction in NYC (Matt Herman, BuroHappold)
L-R: Steve Bluestone presenting with Lisa White, Doug Farr, Matthew Herman

L-R: Steve Bluestone presenting with Lisa White, Doug Farr, Matthew Herman

Really amazing stuff.

Katherine Swenson

Katherine Swenson, Vice President, National Design Initiatives for Enterprise Community Partners — Day 1 Opening Keynote

Of course this growth has been fueled by forward-looking programs that recognize that energy efficient homes make so much sense for affordable housing developers/owners and dwellers. Katie Swenson from the Enterprise Foundation was a breath of fresh air–dynamic, positive, and motivating opening keynote. She explained that in her and her organization’s eyes energy is a critical part in assuring not just housing for people—but healthy housing! “Health is the new green,” she said, and of course passive housing delivers here with excellent comfort, indoor air quality and the added bonus of resiliency when the power goes out. Katie announced that the Green Communities criteria had just included PHIUS+ 2015 certification as one of the highest energy point options.

Other affordable housing agencies also have made a move: the Pennsylvania Housing Finance Agency (PHFA) awarded bonus points in its last round of selecting projects for Low Income Housing Tax Credits. More recently the New York State Homes & Community Renewal (HCR) effort was mentioned in a release regarding energy efficiency measures from the White House. Those agencies now directly encourage passive building standards in their RFPs. Remarkable!

Sam Rashkin, U.S. D.O.E. -- Closing Plenary Keynote

Sam Rashkin, U.S. D.O.E. — Closing Plenary Keynote

On the other coast. Seattle just amended their multifamily building code to allow additional floor area ration (FAR) for projects that meet the PHIUS+ 2015 criteria. That’s a significant incentive for developers.

Things are cookin’!

The core conference, as usual, was chock full of goodness. There were examples of how the new PHIUS+ 2015 climate specific passive building standards helped to optimize costs both here in North America (presentations by Chicago’s Tom Bassett-Dilley, Dan Whitmore, and) and internationally (Günther Gantolier from Italy). There were nuts-and-bolts presentations on wall assembly solutions (Tom Bassett-Dilley again), air and water barrier best practices (Marcus and Keith). And, the Builders Hootenanny—led by Hammer & Hand’s Sam Hagerman, focused on component challenges such as sourcing airtight FDA approved doors for commercial construction.

The U.S. DOE’s Sam Rashkin closed the conference with an unexpected message: he suggested that we needed to rename a few things to facilitate behavioral change. He posited that ZERH, LEED, PHIUS and other green building programs are essentially fossil fuel use rehab centers trying to rehabilitate an addicted nation and to show how it can be done differently. He received a standing ovation.

A few more comments on pre-conference workshops – three WUFI Passive classes drew almost 80 people and they all were super happy throughout the two days! Who would have thought! Happy people energy modeling!

LEFT: Marc Rosenbaum's lecture on Renewables -- RIGHT: Joe Lstiburek on Multifamily Building Science & HVAC

LEFT: Marc Rosenbaum’s lecture on Renewables — RIGHT: Joe Lstiburek on Multifamily Building Science & HVAC

Marc Rosenbaum single-handedly won first place in registering the most people for his class to connect passive principles with renewables to get to positive energy buildings (the logical next step).

Joe Lstiburek placed a close second (sorry Joe) and did a phenomenal job in covering ventilation concerns in large multifamily buildings. Rachel Wagner showed the most awesome cold climate details that I have ever seen. Galen Staengl took folks on a spin to design multifamily and commercial mechanical systems.

And Gary Klein topped it all off by reminding us that without efficient hot water systems design in multifamily, no cigar!

Thanks to all presenters and keynotes! You made this an excellent and memorable event.

I have not even mentioned the first North American Passive Building Project Awards—the entries were just beautiful projects—check out the winners here. I must mention the overall Best Project winner of 2015, as I believe this is pivotal: Orchards at Orenco. What a beautiful project, the largest fully certified PHIUS+ project in the country to date, a game-changer, underlining affordable multifamily projects on the rise.

I’m extremely happy that the Best Projects winners for young CPHC/architects was a tie, and both winners are women! Congrats to Barbara Gehrung and Tessa Smith! Go girls, you are the next generation of leaders!

L-R: Best Overall Project: Orchards at Orenco; Best Project by CPHC under 35 (tie): Island Passive House, Tessa Smith; Best Project by CPHC under 35 (tie): ECOMod South, Barbara Gehrung

L-R: Best Overall Project: Orchards at Orenco; Best Project by CPHC under 35 (tie): Island Passive House, Tessa Smith; Best Project by CPHC under 35 (tie): ECOMod South, Barbara Gehrung

One last note on a thing: Passive building people know how to party while devouring the most challenging, inspiring energy science, details, philosophies (Jevons paradox – Zack Semke’s fascinating lunch keynote) from the field.

And the architectural boat tour on Saturday to top it all off was almost surreal. When we were all out on Lake Michigan and the fireworks went off over the magnificent skyline, I thought, “that’s how we roll :).” Plus, the docent from the Chicago Architecture Foundation was a font of information, and even long-time Chicagoans learned a lot along the way. If you weren’t there, you missed the best passive building party of the year, maybe ever. (But we’ll try to top it, promise.)

Finally, for the crew that just can’t get enough, the Passive Projects Tour on Sunday was, as always, an enormous hit. Tom Bassett-Dilley and Brandon Weiss put together an array of completed and in-progress projects that generated a buzz at every stop. Thanks to Tom and Brandon and to PHA-Chicago for all your help!

Cheers!

Kat

 

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.