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.

Climate Data and PHIUS+ 2015

 

Adam2smAdam Cohen is a principal at Passiv Science in Roanoke, Va, a PHIUS CPHC®, a PHIUS Builder Training instructor, the builder/developer of multiple successful passive building projects, and a member of the PHIUS Technical Committee. With the release of the PHIUS+ 2015 climate-specific standard, Adam weighs in on the importance of climate data sets.

Project teams have always needed to be discerning about climate data sets they use in energy modeling.  Whether it’s WUFI Passive, Energy Plus, PHPP or any other software, the old adage garbage in = garbage out applies. Project teams always must analyze and make a call as to how accurate the climate file is.

For example, I worked on a Houston, Texas project a number of years ago and there were several climate datasets that were close and one that was very different. As a team, we had to decide how to approach this in the most logical and reasoned way.

Recently as I analyzed a Michigan project, I determined that my two dataset choices were “just not feeling exactly right” so I asked PHIUS’ Lisa White and Graham Wright to generate a custom set. I can’t know that this one is exactly right, but I know that it’s as accurate and “right” as we can make it.

Note that when multiple data sets are candidates, it is not just altitude that matters, but location of weather station (roof, ground, behind a shed, etc.). Ryan Abendroth blogged on the subject of selecting data sets (and when to consider having a custom dataset generated) and I recommend you give his post a read.

Since PHIUS+ 2015 is a climate specific standard, it’s all the more important to use the best available.  We all know that bad data is not exclusive to PHIUS (remember the Seattle weather debacle in early versions of the PHPP).

It’s incumbent on project teams to use science, reason and judgment in interpreting climate data sets. Being on the water, in the middle of a field or in the tarmac of an airport makes a difference.

In New York City, for example, we have an oddity: There are three dataset location choices.

A satellite photo of NYC with Central Park outlined. The climate date for the Park is substantially different than that for other parts of the city.

A satellite photo of NYC with Central Park outlined.

One is Central Park, and the PHIUS+ 2015 targets for that are substantially different than the others. But, counter to a Tweet calling into question the validity of the PHIUS+ NYC target numbers, they are different because the Central Park climate data is substantially different – probably due to vegetation countering the urban heat island effect. It has a dramatic and pretty fascinating effect on the microclimate, and the U.S. DOE has a nice read on the subject.

For project teams lucky enough to have access to multiple data sets for their location, by rational comparison, they should be able to make an intelligent decision to use a canned set or to have a custom set generated.

It also more important than ever that the PHIUS+ certifiers to examine the weather data provided by a project teams to see if the project team made a logical, rather then an easy selection of climate data.

In addition, we on the PHIUS Technical Committee will continue to collect and monitor data and will tweak certification protocols as we see the need. But, I remind all my fellow CPHCs that bad climate data sets are endemic in the industry and it is important that project teams make careful decisions and that they reach out to PHIUS staff to help when climate data sets just don’t seem right.