PHIUS+ 2018 Webinar Q&A

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PHIUS Senior Scientist Graham Wright and Certification Manager Lisa White answer questions that were submitted during and after the live PHIUS+ 2018 Webinar on November 8, 2018.

You can view a recording of the webinar at the PHIUS.org site.

*Note: Some questions have been edited for publication

Q: Has PHIUS started to look at overall GWP in the materials used to make these high performance buildings? To save the balance of the climate, reducing our emissions in the next 20 years is critical. Lots of XPS and spray foam make a low energy building but don’t do anything to help our climate goals.

A: The short answer is yes. We do have a GWP impact calculator for insulation. Its use is not required for project certification but we encourage it when we see large areas of XPS or SPF proposed. Our product certification program for construction systems has a requirement for a sustainability or health certification; there are several options recognized.

Q: Can you explain the exuberance concept?

A: We remain enthusiastic about the “tiny heating system” / “tiny heating bill” idea.

Q: Thanks for including Quebec Province! I believe in 2015+, all of North America was calculated according to a blanket value for cleanliness of the grid. Is 2018 adapted to different grids, and how do you deal with Quebec’s very cheap and clean hydroelectricity? Renewables are a tough sell here. Zero government incentives and at 7 cents/kWh, our energy costs would have to more than treble in order to make PV make financial sense.

A: In the standard-setting study itself we used the same factor all the time, but because the buildings were (almost) all electric, it canceled out. The PV generation is multiplied by the same factor as the usage, so source net zero is achieved with the same size PV array as for site net zero.

The philosophy is that CO2 emissions anywhere affect everyone everywhere. We all share one atmosphere, so by a principle of solidarity we should really use the world average source energy factor for electricity. That is, people with clean grids do not get to play “we’ve got ours” and use more energy. Even if your local grid is clean we want to drive additional action such as REC purchases that fund new clean energy projects. In certification we do allow the use of national averages, so we actually just request solidarity at the national level. Canada has a cleaner grid than the US overall, and thus Canadian projects will not have to take as many measures for net source energy reduction. The source energy factor for electricity in Canada is 1.96, whereas it is 2.8 for the US.

The electricity cost does affect some of the space conditioning criteria because higher energy prices justify more conservation measures and thus tighter targets. We calculate this with state-by-state averages, so Quebec projects will have less stringent targets than neighbors in Maine and Vermont.

 

Q: The word “townhouse” usually means a single-family building, but you seem to be using it differently.

A: The individual dwelling units are “single-family, attached”. That is, they share walls but not floor/ceiling. Speaking loosely, the whole row of attached units is the Townhouse, and the study building is 8 or 16 attached units.

Q: Is the mandatory minimum for window upgrades done because it wouldn’t be cost effective otherwise?

A: Yes. Window costs have come down but this still had to be forced in most cases. The starting points were still “in the money” though. There were a few times when the optimizer bought them on its own, but it took a long heating season and high energy price to motivate it. 

 

Q: Is this modeled EUI directly from WUFI Passive in the “Modeled vs. Measured” slide?

A: Yes, the WUFI Passive energy model used for certification.

Q: Do the new non-residential commissioning requirements apply to the common areas of residential buildings or only to all non-residential buildings?

A: TBD. Our current definition (for source energy target purposes) hinges on whether the spaces serve outside clients / customers or just the residents.

 

Q: Are you considering using the last 5 years of climate data vs ASHRAE to deal with global weirdness?

A: No, but we are working on future climate data for 2090 as an informational resource.

 

Q: Any comments on using low-iron glass (easily found in EU / just starting to appear in US)? Does the visible transmittance increase relative to ordinary US glass (which has a green tint to natural light)?

A: Alpen for a while had a low-iron glass option in their certified products, but they discontinued it.

 

Q: Instead of ignoring PV in competing with efficiency measures, why not look at PV with storage for the costs? This may not take care of seasonal differences, but it would take care of daily or weekly changes.

A: We may have have explored it if that was an option in BEopt, but it isn’t yet. Our current thinking is that what batteries do for you depends, in normal operation, on what the time-of-use rate structure looks like, and they are also good for you in outage situations. We are working on a calculation protocol for outages and waiting for utilities or other researchers to converge on time-of-use rate structure(s).

 

Q: Is there an ASHRAE 55 comfort analysis or PMV for PHIUS+?

A: The new window comfort calculator is based on relatively recent research on Predicted Percentage Dissatisfied specifically for draft at the ankle – it doesn’t just hark back to the PMV/PPD that was determined in 1970.

I (Graham) also wrote a paper for the 2016 conference looking at the radiant temperature effect of windows on comfort.

In certification we mostly take the same kind of simple view as in building code, e.g., “thou shalt maintain a dry bulb temperature set point of X and Y”. Sophisticated comfort analyses are more appropriate for workplace and nonresidential cases where clothing and metabolic profiles of occupants can be pinned down (as required by ASHRAE 55), and one might not have to worry so much about frail or sensitive occupants.

 

Comment: Adaptation is why I pursued CPHC in the first place!

Graham Wright: Thanks! Lisa presented on passive survivability at the Boston conference, and we will have more to say about this in the future.

Q: How does the new standard accommodate variable occupancy patterns/equipment usage in non-residential buildings?

A: With respect to the performance targets, as a first step, we will allow two different occupancies to be used to determine the annual demand targets vs. peak loads. Also, we can develop custom criteria for unusual situations (additional fee applies).

With respect to energy modeling protocol, it is already required to enter patterns for occupancy, ventilation and lighting, but this is mostly about getting the annual total energy right for source energy limit purposes.

 

Q: Please define HDD65, IGA, CDD50, TCD, IGCL and DDHR.

A: HDD65 = Heating degree-days, base 65 F;

IGA = Solar Irradiance, global, annual;

CDD50 = Cooling degree-days, base 50 F;

TCD = Temperature, cooling design day;

IGCL = Irradiance, global, cooling load design condition;

DDHR = Dehumidification design humidity ratio.

 

Q: If a project is considering registering under either 2015 or 2018, can we register under 2015 then change to 2018 (as circumstances change) without an additional registration fee?

A: Yes, you can always pursue a newer version of the standard. You are not able to pursue older versions if the contract date is later than the last day to submit under that older standard. In order to register for PHIUS+ 2015, the contract must be submitted before April 1, 2019.

 

Q: Are there updates to WUFI to accommodate the 2018+ standard? And when will it be available?

A: Yes, the next version of WUFI Passive will be released by the end of 2018. We will notify all of PHIUS’ mailing list.

 

 

 

 

 

 

 

 

PHIUS Offers a SMART Path to Carbon Neutral Building

Recently, leaders of 19 of the world’s largest cities announced they would enact regulations to require new buildings be carbon neutral by 2030, and all buildings by 2050.

We at PHIUS wholeheartedly endorse this powerful commitment to sustainable development. We continue to work with all stakeholders in the design, construction, manufacturing, real estate, finance, and government sectors to eliminate the building sector from the global carbon balance. We need to move from a broad vision for a carbon neutral future to specific focus on tangible, actionable steps for these industries that so profoundly affect the built environment.

To borrow from management consulting-speak, passive design is a SMART way to go carbon neutral. For the uninitiated, let’s see how PHIUS is the S-M-A-R-T way to tackle carbon in buildings.

Specific:
PHIUS+ sets limits on net source energy—the total amount of energy consumed through production, conversion, transmission, distribution, and ultimately into useful energy services at the building site. When setting PHIUS targets, we apply a national average source-site adjuster for delivered electric energy to reflect the inefficiency of the electric system and to follow the fair share of carbon principle. Inversely, by specifically increasing efficiency of space conditioning end-uses, we deliver a triple benefit upstream! Through onsite generation, virtual net metering/community solar, and REC purchases, project teams can remove their project’s specific carbon footprint from the bigger equation.

Measureable:
You can’t manage what you don’t measure, so we developed a whole Monitoring Protocol to gauge not just energy consumption, but overall project performance. We also look back at projects in operation to see how they perform compared to the modeled results . Bottom line: across the nearly 200 units and homes we studied, PHIUS projects are within 10% of their predicted (modeled) energy performance.

Attainable
We take the global goal of carbon neutrality and make it attainable for project teams working in their particular climate context by providing tools, training, and technical support. PHIUS+ is the only cost-optimized passive building standard, meaning that exceptional performance is economically viable. Most importantly, we convene a community of practitioners so that professionals can share experiences, insights, and develop best practices to take high-performance building further, faster–making the sustainable…attainable.

Project teams are constantly finding innovative, cost-effective, and elegant solutions to achieve the ambitious (and necessary) energy performance targets. See our Passive Project Design Awards for compelling examples.

Relevant:
As our friends at Architecture 2030 like to put it, “Buildings are the problem; buildings are the solution.” Buildings represent roughly 40% of US energy demand [31% globally], with growth overwhelming increases in efficiency. Passive building at scale could go a long way towards the necessary reduction targets. Moreover, the source energy targets are based on a “global fair share” of carbon emissions.

Time-Bound:
We recognize the magnitude of the climate challenge, and we are committed to taking bold but measured steps so ambitions align with abilities. Like building codes and other rating systems, we have a process to revisit and revise standards every three years. The PHIUS+ 2015 Standard will be phased out in the coming months and replaced with the PHIUS+ 2018 Standard, which sets updated targets, addresses different building types, and allows creativity and flexibility to achieve the performance targets.
Get SMART with your plans to positively impact the future, and join the community of practice that’s forging the passive path to meaningful climate action.

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.
5-Passive-Building-Design-Principles

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).

9_Foundations_Healthy

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.