An article in ArchDaily details the nine aspects of a building that, according to the Center for Climate, Health, and the Global Environment at Harvard University’s School of Public Health, make that building a healthy place for people to be. The ArchDaily article summarizes a 36-page report called The 9 Foundations Of A Healthy Building. It is not a surprise to PHIUS what the nine items are, or that PHIUS+ certification is the most cost-effective way to get there (more on that later).
A summary of Harvard’s Nine Foundations of a Healthy Building:
Ventilation — Replace stale indoor air with filtered outdoor air. Test, maintain and monitor equipment regularly.
Air Quality — Eliminate items that offgas, remove legacy pollutants (lead, asbestos, PCBs), limit moisture intrusion. Relative humidity should be kept between 30% and 60% to reduce mold and mildew odors.
Thermal Health — Control humidity and temperature striations. If occupants need control of the thermostat, make that easy. Also, stick to a regular maintenance schedule to make sure equipment is running efficiently.
Moisture — Roofs and walls should not leak, plumbing and HVAC equipment should not condense or leak, and condensation spots (cold spots that become mold spots) should be eliminated or monitored (this is done with continuous insulation, as explained later).
Dust & Pests — Surfaces should be clean, and vacuum filters should be high efficiency because dust is a reservoir for allergens and chemicals. Generally, the focus is on preventing problems (more about solutions below). Airtight construction, described below, also keeps pests out (including bed bugs in apartment buildings, through compartmentalization).
Safety & Security — the items outlined in this section are required by building codes, including fire and carbon monoxide detectors, lighting in stairwells, egress, entry, and parking areas.
Water Quality — beyond a city water supply that meets water quality standards, consider water purifiers and microbial control. Plumbing layouts should be designed to minimize stagnation in pipes.
Noise — beyond outside noise, indoor noise should be controlled. Background noise should be limited to 35db with a maximum reverberation time of 0.7 seconds.
Lighting & Views — Daylighting should be abundant in natural blue light, evening lighting should be devoid of it. Views to the outside and outside-inspired interior themes connect people to nature which can significantly improve recovery from stress and mental fatigue while boosting their cognitive performance.
While nine items is a little more than most people can recall quickly, the point of the Harvard exercise was not to make a snappy list that people could quickly remember but to make a list that accurately reflects healthful buildings. Fortunately for high-performance builders and designers, PHIUS can shorten the list.
Check back later this week to see how the Harvard Healthy Nine translates to the PHIUS Phive!
A feverish buzz builds in Alison Kwok’s University of Oregon classroom as students scramble to
complete final details of architectural elevations, double-check load calculations, and precisely
This cohort of aspiring practitioners join a growing number of design students getting a jump start on their sustainable design careers by obtaining CPHC credentials while still enrolled at their institutions. To date, five institutions have formed partnerships with PHIUS to provide CPHC training: University of Oregon (OR), Miami University Ohio (OH), Prairie View A&M (TX), Ryerson University (ON), and Ball State University (IN). Most students who earn CPHC in school are practicing with firms within a year.
The CPHC curriculum and modules are largely the same as the weeklong trainings PHIUS regularly provides, with some important modifications. Professor Kwok sometimes opts to invite professionals as guest lecturers to cover content like WUFI modeling, while instructing on other items like assembly calculations of details herself (she is co-author of Passive House Details, with Donald Corner and Jan Fillnger). Other faculty instructors use the culminating product—developing a PHIUS+-compliant design—as more of a collaborative studio project than an individual take-home. This applied learning allows students to iterate through the design process while allowing collaboration, guidance, and peer exchange.
“They were motivated to learn the material again and were appreciative of getting into the depth that the PHIUS materials offered. The opportunity to become a Certified Passive House Consultant through a course tailored to their schedule was incredible!” said Professor Kwok.
These emerging professionals are already applying their building science knowledge and skills to great impact, while building portfolios and relationships with industry veterans.
The Race to Zero National Student Design Competition was one recent venue where the rising stars of sustainable design were able to really shine. This annual contest began with 84 teams from 68 institutions spanning eight countries, all vying for the best project in one of five categories: single family detached (suburban/urban), single family attached, small multifamily, and elementary school. The finalists were invited to NREL in Golden, Colorado this spring to present their projects before peers and distinguished judges (including PHIUS Executive Director Katrin Klingenberg).
Four of the finalist teams—Prairie View A&M, Miami University, and Virginia Tech—were led by students who had earned the CPHC credential through their university. Other teams, such as IIT, were supported and mentored by established CPHC professionals.
We’ll be featuring more stories from emerging CPHC professionals in the coming weeks. And be sure to join us in Boston for the 13 th Annual North American Passive House Conference, where Race to Zero winners will be presenting on their winning submissions.
On a sweltering hot and humid summer morning last week in Washington DC, PHIUS staff joined community development and design professionals from both sides of the Atlantic on a tour of sustainable social housing. The visit to Weinberg Commons, the first affordable multifamily retrofit project to earn PHIUS+ certification, capped the weeklong DC Energy Future Exchange Tour, organized by the Ecologic Institute.
The tour was led by Koray Aysin of HousingUP with Donna Rosano of Zavos Architecture + Design and Matt Fine, CPHC (formerly with Zavos). The guides described in detail the challenges and creative approaches they applied to renovate a dilapidated group of garden apartments into healthy, dignified, affordable homes for families of limited means—while also achieving ambitious energy and environmental targets. Because the developer, Housing Up, also pays the utilities, they had an incentive to invest in the building’s energy efficiency, knowing that the benefits would exceed the costs down the road. Some of the strategies the team used to hit stringent PHIUS+ energy targets included:
Specially designed window boxes that block solar heat gain while allowing natural light to enter the dwelling areas
Outboard insulation applied between vertical joist, a creative approach to a structural challenge
Energy recovery ventilation that reuses energy from indoors to pre-heat or cool thefresh air stream
Exceptional air tightness of 0.58ACH 50. This result is remarkable in new construction, and even more difficult to achieve in an existing building
A Variable Refrigerant Flow system that allows different sides of the building to heat and cool simultaneously. Due to superior insulation and air-tightness, all twelve units in the building are served by just one 2 ½ ton condensing unit—typical of a large single-family house.
Solar hot water panels and a basement storage tank; this results in a 40% cost savings
Rooftop solar electric panels developed by a third party, which sells back to the apartment at a rate 50% lower than grid purchase
Attendees were also able to see passive performance in action. While the tour started on a hot, loud street, discussion continued in the cool and quiet of the community room, thanks to the well-executed features. Here, participants learned about the financial aspects of the project. Financing sources included federal Low Income Housing Tax Credits, local housing funds from DC DHCD, funds from the DC Department of Behavioral Health, and philanthropic support.
Check out our Multifamily Resource page for concepts and case studies applying PHIUS standards to affordable housing. Then sign up to join us in Boston on September 20 for a pre-conference workshop with leading practitioners in design and community development.
Wednesday night, dozens of local designers, builders, and residents gathered to see how passive principles are applied in projects—and how they can give us a jump start on a clean energy future. PHAUS’ Chicago Chapter organized an in-depth guided tour of Tierra Linda, a PHIUS+ project currently under construction in Chicago’s Humboldt Park neighborhood. This affordable 6-unit building, developed by LUCHA, is vying to be the first PHIUS+ multifamily project in Chicago. It also shows how good design is the first step in making the sun our primary source of power.
So, how far does solar power go? Technically, energy from the sun, our friendly fusion reactor, travels about 93 million miles, or 7 light-minutes, to reach Earth. However, if you want to know how far solar power will go to meeting your home, business, or community’s energy needs and sustainability goals, you need to start with some critical questions and concrete examples.
As an energy efficiency evangelist, I often take umbrage when a news story says that a new power plant will produce “enough energy to power X homes.” Usually, that number’s about 750-1000 homes per megawatt, or 7.5-10kW per home. But how many GOOD homes would that same facility power?
To even approach numeric goals for climate, we need to address both supply and demand, numerator and denominator, at the same time.
This is where passive building comes in. By investing in the “passive” (i.e., nonmoving) parts of a building like walls and windows, we can significantly reduce the need for “active” systems like HVAC—and the energy to run them. The PHIUS+ standard sets cost-optimized energy targets based on local climate, building geometry, and occupancy.
If you start with minimal loads, it’s easier to meet them completely with clean energy. This is not complicated conceptually or practically. There is more opportunity to conserve energy in a building than to make it on the roof. The PHIUS+ limit on source energy makes sure that projects focus on efficiency first.
The table below compares the two scenarios PHIUS staff and the project team evaluated for the Tierra Linda project.
Annual Energy Use (kWh)
EUI (kBTU/sf/yr) 39.3
PV needed for NZE 86kW
If the project had been built to Chicago’s already stringent energy code, it would need a very large solar array. The extra 64 kW of solar would have cost $200,000 more. Even if there were room in the budget for that, there wouldn’t be space on the site! The team was able to eliminate equivalent energy use through passive techniques like insulation, air sealing, and energy recovery ventilation that will deliver comfort and savings to the residents—even on cloudy days in the depths of the Chicago winter.
Check back to the Klingenblog for more about how PHIUS+ is helping a clean energy future get made—even in the shade.
Thanks to all of you who took the time to join us for last week’s webinar on the differences between the PHIUS and PHI passive house and building standards. Due to popular demand (we sold out within 3 hours of the original offering) we had to get a bigger “boat” and were eventually able to get everyone seated!
Clearly, there is a lot of interest in the topic.
Two passive building design/construction standards are available in the North American market: The PHIUS+2015 Passive building Standard certified through the Passive House Institute US and the Passivhaus Standard certified through the German Passivhaus Institute.
We presented the webinar in response to growing confusion about the differences between standards and questions about how the programs compare to commonly used energy standards such as ASHRAE 90.1. Other common questions: Are they simply “two flavors of the same thing” or are there more fundamental differences between programs? Which program is more commonly used in North America’s widely varying climates and why?
As we all make progress in mainstreaming passive building to significantly reduce carbon globally, one lesson has become clear: details matter! Different standards and modeling protocols offer significantly different guidance to designers seeking cost- optimized, high-performance buildings in their region.
The European standard and its design parameters for energy comprise one target for heating and cooling to attain an optimized design solution in all climates and cost structures worldwide. The PHIUS+ tailors and optimizes energy targets for both climate and cost, and does so for every individual location. The updated 2018 version becomes even more granular by taking occupancy and building typology into account.
Two very different approaches.
If you missed the live webinar, you can still learn more about the differences and modeling protocols: A recording of the webinar is now online!
Some of the questions that were asked during the webinar and could not be answered are posted below and if you have any other questions please send us an e-mail at email@example.com.
Thanks again to all of you who attended!
A selection of Questions posed during the webinar event, that could not be addressed live due to time constraints:
When will PHIUS+2018 come into effect? How long can we continue to use 2015 for projects in development?
What can we carry forward as a message from PHIUS & you to building code legislators?
We have put a lot of thought into making PHIUS+ a good standard for how much the building sector contributes to climate goals and/or the renewable energy transition, while also protecting occupant health and comfort. We have given it features to make it suitable for policymakers to incentivize. We can do feasibility studies for specific model buildings in specific climates to give officials a better feel for what PHIUS+ requires and delivers.
It is my experience that PHIUS at this time does not accept published efficiencies of ERV’s, and therefore the derated efficiency of ERV’s are not compatible with PHIUS certification requirements.
We accept 3rd-party ratings from AHRI, HVI, and PHI as well as our own product program – only unverified manufacturer data is derated. For building project certification there is not a hard requirement on recovery efficiency for the ventilation, but yes, in some climates it will be hard to meet the other performance criteria without a good H/ERV.
Can you expand on the adaptation aspects of passive house for the changes which are observed and expected in climate?
Right now, our certification is based on TMY3 climate data, and will update when newer data becomes available. Although predictive future TMY climate data sets exist, these are not used for certification. Even so, the performance upgrades required to meet our criteria should provide resilience benefit against weather extremes and utility outages. Resilience and adaptation to changing climate can be evaluated in a different way, more focused than modeling a typical year for predicted energy performance. We are working on a form of resilience assessment for that purpose.
Followup comment by another attendee: I took the climate question to mean: if standard is zone-variable, can we on top of that adapt to how existing zones are shifting to becoming one zone warmer.
We are working on calculations that would generate climate data taking possible changes into account.
Wasn’t PHI’s cost-optimization based on integrating ventilation into the heating ducts and not cost of PV?
The idea was to improve/invest in the envelope to a point so that a typical heating system, and the cost associated with it, could be eliminated. The now minimized heating system could be integrated in the ventilation supply air stream using the same fan and ductwork for delivery. In Germany, eliminating the heating system supposedly made up for the additional cost to improve the envelope. In the U.S., because ducts and furnaces are relatively cheap, that strategy does not net much if any savings after one adds the HRV. PHI did not include cost of PV at the time because it was cost prohibitive. In the U.S. today PV is no longer cost prohibitive and at some point becomes competitive with insulation. Yes, the point was that in the U.S., because ducts and furnaces are relatively cheap, said integration doesn’t net much if any savings after you add the HRV.
Has E-Quest been calibrated against measured building performance for a large sample size of buildings?
I would assume so, it is widely used for code compliance modeling.
Is there a bigger sample size of monitored data on single family homes like the one in Oregon?
Is there any measured data to correlate with the modeling comparisons on Slide 27?
The NYSERDA study was on model buildings not actual, so we can’t get a direct comparison in that case.
In the future will there be more resolution than the ASHRAE climate zones for space conditioning criteria?
In all likelihood yes.
Going back to the financial graph, would you say that solar thermal is pretty incompatible with PHIUS or could it still be useful in certain climate areas?
At this point it appears not to be very cost-effective, but it could still have a resilience benefit in some climates. System complexity works against resilience, and climates that require freeze-protection tend to have more complicated systems.