Isaac 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.