Healthy Buildings, Part 2: The PHIUS Phive

Earlier in the week, we discussed the Harvard TH Chan School of Public Health’s 9 Foundations for a Healthy Building.

When building to minimum building code standards, these items do not seem connected because the building is not designed as a system as much as it is designed as a collection of parts. Building codes are minimum standards that aim to ensure health and safety concerns are less of a concern for consumers. In high-performance building, such as passive building, a lot of these items piggy-back on each other. For example, proper ventilation and thermal control tend to improve air quality while reducing moisture, dust mites, and pests. Thermal control also generally improves acoustical comfort. PHIUS+ certification specifies continuous insulation, airtight construction, and proper ventilation using small and quiet mechanical systems and great windows. Other aspects on the list of nine—which affect indoor environmental quality, but which are not required for PHIUS+ certification (daylighting, acoustical comfort)—are often part of the PHIUS+ package because that is just good design, and PHIUS buildings are designed by people who give a damn.
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The five PHIUS+ principles:

1/ Continuous insulation

By completely wrapping a building with insulation, heat can no longer sneak out through framing, which has a lower R-value than the surrounding insulation. The simplest way to fix all of those energy sieves is to avoid building them in the first place. Continuous, thick, insulation on the outside of a building keeps heat flow to a minimum.

 

2/ Airtight construction

While thick, continuous insulation can stop a significant amount of heat loss through conduction, plugging air leaks can slow heat flow, too. Because temperature drives air movement—think about convection loops—the air moving through buildings usually carries a lot of heat with it. So here’s the rub: Warm air can hold more moisture than cold air. So when warm air leaks through electrical outlets into exterior walls, it dumps moisture into wall cavities when the moist air hits the cold wall sheathing. It happens in winter and summer, only in reverse.

 

Sound waves also travel on air currents and through framing members, so these first two principles have the added effect of better sound control.

 

3/ Optimized windows

The appropriate window depends on your climate zone; cold climates need well-insulated windows because the temperature extremes are significant. Hot-climate windows typically have strong radiant-heat blockage because the sun is intense in hot climates. Another aspect of windows is shading, which can reduce glare and overheating, and is often cheaper that additional window technology. Regardless of climate or wall elevation, very good double-pane and triple-pane windows which are designed to be airtight are great from an acoustical perspective, they tend to be super quiet.

 

4/ Balanced ventilation

Air-tightening means that dirty, moist air isn’t leaking into the living space from basements and loading docks, which is good. It also means that stale indoor air is not leaking out, which is bad, so air changes must be controlled with some sort of high-tech fan. With balanced ventilation and a tight envelope, a constant flow of fresh air flushes the living space and conditions it to be perfect for human comfort.

 

Ventilator filter required min Merv 7, highly recommended to be MERV 13

 

5/ Minimal mechanical system

Because the building is super-tight, super insulated, and has super windows, a super-size heating and cooling system is unnecessary. A great side effect of minimal mechanical systems is that they are much more quiet.

 

When these five principles are applied to buildings, you get predictable performance, unmatched comfort, superb air quality, and resiliency in the face of power outages due to winter storms or summer blackouts. We can say that PHIUS+ is the most cost-effective path to the Harvard list of healthy building foundations because the core objectives of PHIUS+ address the concerns of healthy building. Healthy buildings are a byproduct of PHIUS+ certification.

 

Best of all, because PHIUS+ buildings consume so little energy, zero energy is easily within reach.

 

Healthy Buildings, Part 1: 9 Principles

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).

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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!

PHIUS, Universities Partner to Train Emerging Passive Professionals

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
label drawings.

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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.

PHIUS Joins US, EU Delegates to Tour Affordable Passive Buildings

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.

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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

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  • 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.

Celebrating Summer Solstice in Chicago

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.

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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.

IECC 2015 PHIUS+
Annual Energy Use (kWh) 112,000 43,000
EUI (kBTU/sf/yr)                              39.3 16.8
PV needed for NZE                         86kW 22kW

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.

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