Policy Update: The Massachusetts Stretch

isaac pic

Isaac Elnecave, a member of the PHIUS certification team, has written this update on the Massachusetts stretch cove, the latest installment of his policy updates.

Over the last 8 years, Massachusetts has made significant progress towards making the passive house (PHIUS+) standard an integral part of its building energy code. This effort points the way to the end goal of creating a cost-effective net-zero energy code.

Besides its statewide base energy code, which is an amended version of the latest International Energy Conservation Code (IECC) model code, the Board of Building Regulations and Standards (BBRS) in Massachusetts has, since 2009, promulgated a “stretch” energy code. The base energy code governs the minimum energy saving requirements in buildings throughout the state. The requirements include: the amount of insulation required in ceilings, walls and foundations; window performance; the level of air tightness; ventilation requirements; the efficacy of lighting and the efficiency of HVAC equipment. It is often described as the worst possible building (from an energy perspective) that can legally be built.

A stretch energy code incorporates similar measures and design approaches but mandates energy efficiency requirements that result in higher performance buildings than those meeting the base energy code. While the base energy code is the default requirement across all towns and cities in the Commonwealth, the stretch energy code must be affirmatively adopted by local municipalities that want to enforce it (at which point, it supplements and overrides the base energy code in that jurisdiction). Importantly, unlike New York State, because the BBRS approves the stretch code, municipalities that adopt it cannot amend it.

In both the Base and Stretch codes in Massachusetts, there is a section for alternative compliance strategies, which specifically includes passive house in both the low-rise residential energy code chapter and the commercial energy code chapter. Under the requirements of its current edition, and in fact since 2012, in any jurisdiction that adopts the stretch code in Massachusetts, a PHIUS+ certified passive house automatically meets code. The current code amendments specify that the annual heating demand for PHIUS certified home or commercial building must be less than 10 kbtu/ft2/year; a value easily met by all certified PHIUS buildings.

The latest edition of the Massachusetts stretch code has just been adopted but has not yet been promulgated* — the expected promulgation date is February 8, 2020 with an effective date of Aug 8, 2020. There will be two significant changes. First, PHIUS itself has updated its standard to PHIUS + 2018 from PHIUS + 2015. Second, with this new edition, a residential or commercial building will be code compliant when it passes the pre-certification stage (much like saying a typical house is given code approval once the plans have been approved.) The updated energy code, based on the IECC 2018, shifts the passive house compliance option from the 10 kBtu/ft2/year metric to an option to seek PHIUS precertification prior to pulling a permit. A project must demonstrate that it has been submitted for final certification by PHIUS to receive the certificate of occupancy. Because PHIUS maintains a rigorous review process through the end of construction, this approach ensures a high quality of construction.

Passive house certification requirements are significantly more stringent than even the other alternative paths in the stretch code (the most commonly used path in the Massachusetts residential stretch code allows for an Energy Rating Index score of 55, which is well above the score typically achieved by a certified passive house).

Massachusetts provides an excellent example of how to use incentives to spur the development of high-performance buildings. Mass Save®, the statewide energy efficiency program in Massachusetts, launched a mid- to high-rise passive house incentive program in the summer of 2019. In the first 6 months over 40 projects with over 3,000 passive house units in development have signed up for the program.  As more projects are built meeting PHIUS standards either through the stretch code or through Mass Save, the universe of designers and builders who become proficient in the construction of high-performance builders grows. This proficiency will result in greater confidence among construction professionals and lower costs with respect to high performance buildings.

As the PHIUS standard includes a pathway to net-zero construction, including it in the stretch and base energy code provides a path for future improvements. In Massachusetts, stretch code development will now focus on a ‘net-zero’ code to run alongside an amended IECC 2021 base code. Having the passive house pathway in the energy codes has introduced designers and builders to the tools and techniques necessary for building cost-effective net-zero single-family and multi-family dwelling. PHIUS looks forward to working with Massachusetts Department of Energy Resources, BBRS and other key stakeholders in making a net-zero code a reality.

Massachusetts in one of three states and one municipality that have incorporated the PHIUS standard in the energy code. New York was discussed in a previous blog (Policy Update: New York State, Two Steps Forward, One Step Back, January 16, 2020). I’ll discuss efforts in Washington State and the city of Denver in a future post.

* Adoption means voting and signing by government official. Promulgation (it specifically means the decree that puts a law into effect), in practice, refers to when the agency in charge of enforcing the law signs off on the rules and regulations relating to the law.

 

Policy Update: New York State—Two Steps forward, One Step back

isaac picIsaac Elnecave, a member of the PHIUS certification team, has written this update on the New York State stretch cove.

Over the last year, the state of New York has made significant progress towards making the PHIUS+ standard an integral part of its energy code. It points the way to the end goal of creating a cost-effective net-zero energy code.

Besides its statewide base code, the New York State Energy Research and Development Authority (NYSERDA) promulgates a “stretch” energy code (NYStretch-2020). The base energy code governs the energy requirements in buildings throughout the state. The requirements include such items as: the amount of insulation required in ceilings, walls and foundations, window performance, the level of air tightness, ventilation requirements, the efficacy of lighting and the efficiency of HVAC equipment. It is often described as the worst possible home that can legally be built.

A stretch energy code incorporates energy efficiency requirements that are more stringent than the base code (NYStretch-2020 is roughly 11% more energy efficient than the base code). While the base energy code is the default requirement across jurisdictions in the state, the stretch energy code must be affirmatively adopted by local municipalities (authorities having jurisdiction) that want to enforce it—at which point, it overrides the state code in that jurisdiction).

Besides providing energy savings beyond the base energy code, NYStretch-2020 was developed with the following goals in mind:

• Technically sound
• Thoroughly reviewed by stakeholders
• Written in code enforceable language
• Fully consistent with the 2018 IECC, ASHRAE 90.1-2016, and uniform codes

Moreover, NYSERDA strongly encourages, but does not require, that a jurisdiction adopting the NYStretch-2020 do so without making amendments.

In NYStretch-2020, there is a section for alternative compliance strategies (R-408), which specifically names passive house; a single-family home or low-rise multi-family certified under PHIUS+ would automatically meet code. The stretch code specifies that the specific space heat demand and (sensible only) cooling demand, as modeled and field-verified by a CPHC (Certified Passive House Consultant), must be less than or equal to 9 kBTU/ft2/year. A dwelling unit shall also be tested with a blower door and found to exhibit no more than 0.05 CFM50/ft² or 0.08 CFM75/ft² of air leakage. Ultimately, to provide a Certificate of Occupancy, a code official must submit a form that must indicate that the finished building achieves a CPHC verified specific space heat demand of less than or equal to 9 kBTU/ft2/year.

It is important to note that the PHIUS standard is even more energy efficient than the requirements in NYStretch-2020. Here is a link to NYStretch-2020: file:///C:/Users/phius/Downloads/NYStretch-Energy-Code-2020%20(7).pdf.

New York City
New York City provides an example of the importance of the stretch energy code. Local law 32 requires the city council to adopt the New York State Stretch code (allowing the inclusion of amendments). The language of the law is fairly clear:

Submit to the city council proposed amendments to this code to bring this code up to date with the most recent model stretch code published by the New York State Energy Research and Development Authority, provided that such model stretch code is more stringent than the New York State Energy Code in effect when such proposed amendments are submitted and provided further that such model stretch code was first published no more than three years before such proposed amendments are submitted;

As noted in the previous section, NYStretch-2020 is significantly more energy efficient than the base state code. Consequently, the city council is about to adopt NYStretch-2020 with one very important and unfortunate exception. R408, the section of NYStretch-2020 which allows for an alternate compliance path using PHIUS+, has been deleted. Here is a link to the proposed energy code  (Click on Int. No. 816 for the text of the code).

It is unclear as to why section R408 was deleted but it removes an important alternate compliance option for designers and builders. PHIUS+ incorporates both rigorous design standards with robust quality control protocols to ensure that the building is both energy efficient and well-constructed.

As the PHIUS standard is more energy efficient than the provisions of the NYStretch-2020, it also provides a target for future code improvements while giving designers and builders the time to develop expertise in building energy efficient dwellings; ultimately leading to the establishment of a net-zero energy code.

A Climate Action Turning Point!

That's friend of PHIUS and visionary NYC architect Chris Benedict (l) with Katrin Klingenberg.

That’s friend of PHIUS and visionary NYC architect Chris Benedict (l) with Katrin Klingenberg.

On October 29th I was fortunate to attend the NYSERDA low carbon and zero energy Buildings of Excellence Awards at the Building Energy Exchange in New York City. What a terrific time for projects that are about to and that have employed PHIUS+ passive building standards as baseline to get to zero energy ready! I counted at least 10 PHIUS+ project teams in NYSERDA’s three categories, Early Design Stage, Substantial Completion and Completed, that were awarded up to 1 million dollars for their projects!The awards were announced on the 7th anniversary of super storm Sandy, not a coincidence, as a reminder for urgent climate action. Seven years later, NYC is leading by action and is putting itself firmly on the path of global leadership in building energy and resilience. Thank you to an amazingly dedicated NYSERDA team for making this happen!

The week before the event, I keynoted the Boston Passive House Massachusetts Symposium to talk about the evolution of the PHIUS+ certification suite for passive buildings, and why they provide such great value on the path to ZERO. Here as well, political action was taken to combat climate change: MassSave staff announced significant incentives for low carbon and zero energy buildings and significant additional incentives if project teams go for passive building certification for their hi-rise residential projects. Certification requests from Mass have increased manifold as a result. Massachusetts in not far behind NY State in political will, turns out.

And just a few weeks before the Boston event, it was gratifying to find that at the Getting to Zero Forum in Oakland, California, passive building was simply understood as the logical starting point on the path to ZERO, no questions asked. During one of the plenaries the ASHRAE speaker proudly introduced the new ASHRAE standards committee: 227p Passive Building Design Standard. That was great news and evidence that ASHRAE is moving on the topic.

During the lunch plenary on day one the National Renewable Energy Laboratory featured PHIUS board member Mary Rogero’s students presenting their Solar Decathlon winning PHIUS+ Source Zero energy school design. For the closing plenary, California’s Commissioner Andrew McAllister presented on his recently completed and only recently occupied zero energy passive house in Berkeley and the benefit of energy independence. He had electricity while PG&E had shut off power supply to prevent fires, a consequence of climate change, to most of Berkeley including the entire Berkeley Campus. He was followed by Greg Hale, from NYSERDA, who spoke about applying the Energiesprong passive plus zero energy retrofit approach that he is spearheading in NYS and other zero carbon measures taken by the city.

And while most of the building action seems to be happening on the East Coast, quietly behind the scenes advocates have been working hard to get passive building into codes all over the country. When PHIUS was first established our lofty mission was to make passive building code by 2020. As ambitious a goal that was then in 2007, we have made significant progress toward it, and have paved the path for national success. NY State has included passive building as an alternative compliance path into the next stretch code and Washington State is on a similar path. Massachusetts has included an alternative compliance path for passive buildings and verification tools (no double modeling required) and Washington, D.C. also has included an alternate compliance path for passive buildings in their about to be launched ZERO Energy Code.

Most significant of all those developments is the establishment of the ASHRAE 227p standards committee. If successful they’ll created a passive building design standard that takes the best pathways from all existing programs and develop an even better, easily adopted design standard globally. That committee has now started its so very important work. The ball is rolling! Stay tuned for more!

Exciting times, indeed!

 

 

 

 

WUFI® Passive V.3.2.0.1 validation using ANSI/ASHRAE Standard 140-2017

Good news: PHIUS has completed modeling to validate WUFI Passive according to ASHRAE 140. Read the full report here

ASHRAE 140 is a comprehensive Standard Method of Test (SMOT) for the evaluation of building energy analysis computer programs. The ASHRAE 140 report provides the information accrediting agencies or jurisdictions need for validation or acceptance of WUFI ® Passive for code and policy purposes. In short, the standard describes test buildings (cases) in significant detail in order to model the building and compare results versus other software. It contains a comprehensive description of test procedures, as well as predictions generated by WUFI Passive software evaluated against predictive benchmarks.

The table below provides a description of the test cases used for ASHRAE 140 Validation. 

Table 1

Annual Heating and Annual Cooling Load results were reported for most cases, except for L302-L324A which only analyzed heating. WUFI Passive results fell well into the suggested acceptance ranges in all test cases when following Class II Procedures of ASHRAE Standard 140.  Most results fell toward the center of the confidence range as shown in the graphs below.
AHL Results

ACL Results

Authors: Lisa White, Jasmine Garland

 

A mid-cycle tweak of PHIUS+ 2018

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Space conditioning targets have been adjusted to reflect a statistical ‘Inclusive Fit’ rather than ‘Best Fit.’

PHIUS officially launched the PHIUS+ 2018 Passive Building Standard just over a year ago at the 13th Annual North American Passive House Conference in Boston. The passive building market seems to approve: not only have we gotten a lot of positive feedback from CPHCs and other design professionals, but PHIUS+ Certifications continue to increase. The most notable upgrades from the PHIUS+ 2015 standard add nuance to the space conditioning targets, adjusting them for building size and occupant density – passive building professionals do seem to appreciate this.  Another notable upgrade provides tiered source-energy targets and methods to hit those targets, depending on project goals.

Through the end of September 2019, PHIUS certification staff had the discretion to grant an exception for one of the four main space conditioning target criteria, as outlined in PHIUS+ 2018 Passive Building Standard-Setting Documentation, page 6. This allowance gave teams with projects already in planning some assurance that their efforts would not be wasted if their designs could not be revised to meet the new targets.  If a project was severely constrained on meeting a target, a “mulligan” could be granted based on majority vote from the certification staff. This also allowed flexibility in case the targets didn’t pan out in the real world even for clean-sheet designs.

Read the Full, Detailed Tech Corner Article

This “3 out of 4 ain’t bad” provision has now come to an end, and we have learned a lot from the many projects that have gone through the process. These case studies have allowed us to complete a mid-cycle evaluation of the standard. Determining optimum performance targets is an iterative process, and gathering feedback for future improvements is part of it. Thank you to all the teams that have certified to PHIUS+ 2018 helping us to dial in these improvements.

Moving forward, space conditioning targets have been adjusted to reflect a slightly different statistical fit from the original space conditioning target-setting process — an ‘Inclusive Fit’ rather than ‘Best Fit’ line. These updates will not disqualify any previously submitted projects in the PHIUS+ 2018 Certification process, as they are more inclusive than before. One sample graph of this is shown for the Peak Heating Load.

The Space Conditioning Criteria Calculator has been updated.

The Space Conditioning Criteria Calculator has been updated.

The resulting updated targets will be:

Cooling Demand = Original Target + 2.81 kBTU/ft2yr 

Heating Load = Original Target + 0.77 BTU/ft2hr

Cooling Load = Original Target + 0.45 BTU/ft2hr

The PHIUS+ 2018 Space Conditioning Criteria Calculator v2 has been updated to reflect the updates. Note the ‘v2’ at the end of the naming convention. 

Note

  • Projects with a contract date before October 1, 2019 may utilize only one path, (1) Use the updated calculator ‘v2’ or (2) Meet 3 of 4 space conditioning targets as described above.
  • Projects with a contract date after October 1, 2019 may only use the updated v2 calculator.

More details on this, as well as the graphs supporting the statistical analysis can be found in this Tech Corner Article