The Developer's Guide to GreeNYC, Part I

By this point you have surely heard of COVID-19, but what about ECC-20?

Of course, I mean the NYC Energy Conservation Code of 2020!

The update, which rolled out in May of last year, adopts the “NYStretch” code by going 10% beyond the 2018 International Energy Conservation Code (IECC), which the State uses as a baseline. Currently only 11 states in the country use IECC 2018, so the City has clearly put itself far ahead of the pack in the charge towards net zero.

On top of that, the City enacted the Climate Mobilization Act of 2019 (also known as the #GreenNewDeal4NY), which claims to be “the largest climate solution put forth by any city in the world”. Aiming for “40x30” (40% reduction in greenhouse gas emissions from buildings by 2030) and “80x50” (80% reduction by 2050), it imposes severe fines for buildings that do not comply with proscribed emissions caps, which includes 75% of qualified buildings in the City.

While the City has had energy codes in affect for over a decade (since the Greater Greener Buildings Plan of 2009), most owners and design professionals have gotten away with ‘greenwashing’, finding ways to sweep the requirements under the AstroTurf.  These latest iterations, however, have pushed the envelope so far (pun intended), that nearly every new and existing building in the City now requires a sophisticated energy analysis to accompany your proforma and statement of cash flows.

Beyond simple compliance, costs and (yes) savings associated with sustainable building practices, all this regulation can have extreme design implications.

Beyond simple compliance, costs and (yes) savings associated with sustainable building practices, all this regulation can have extreme design implications. More efficient exterior wall and roof envelopes typically mean thicker walls, which eats up your floor area. While the thrill of floor-to-ceiling glass feels like you’re flying in the Manhattan sky, that thin layer of glazing doesn’t do a whole lot to keep the cold air out or the hot air in. Maybe you’d prefer to settle for some punched windows on your $35m condo?

But don’t worry, the future does not have be all EIFS and solar panels. With a holistic understanding of how the Code works, its priorities and compliance paths we can keep our projects on budget, on time and looking spectacular. Along the way, we can develop more sustainable portfolios, which save cost in the long run through energy reduction and careful detailing, improve the quality of life for occupants, and contribute to the broader reduction of greenhouse gas emissions into the atmosphere.

The first in a series covering this topic, this article takes a look at the Energy Conservation Code and how your choice of compliance method can affect the building design and proforma. Coming articles include a look at Carbon Emissions, Sustainable Roofs, and more.

Energy Analysis

Before digging too deep into the details of the different systems and requirements of the Code, we first have to understand how we actually prove that our buildings pass the test. Specifically, DOB provides three options, or “Compliance Paths”:

1. Tabular Analysis: The most basic path. Just list all the requirements and how you have met them. DOB even provides an Excel template to help you check all the boxes. Because it evaluates every condition based on the worst-case scenario, it typically works best for alterations and other projects of limited scope. On larger projects the 'one-size-fits-all' model can lead to added cost that you can mitigate with a more thorough analysis.
2. COMcheck: A basic text-based software developed by the U.S. Department of Energy to show building compliance with energy codes, COMcheck operates on a ‘performance’ model, as opposed to the ‘prescriptive’ model for Tabular Analysis. This allows you to use envelope ‘trade-offs’ to overcompensate in some areas of the building and take it easy in others. For example, adding a few extra inches of insulation on your roof may let you add some of that glass back in the mix.
3. Energy Modeling: More complex than a COMcheck, an Energy Model uses a digital 3D model built in special DoE2 approved software packages. Taking it a step beyond the COMcheck, DoE2 allows for trade offs between heating/cooling systems and the envelope. Buildings with complicated geometry, an excessive number of thermal breaks (like wraparound balconies), or other unique design features might require this extra step of analysis to show compliance.

The Upshot

To put things in perspective a bit, the exact same building may fail under the Tabular Analysis, pass with a COMcheck and show a 10% energy savings with an Energy Model. In terms of the construction budget, that 10% savings in performance may highlight an opportunity for value engineering, by reducing the thickness of the insulation, for example.  The increased cost in design for a more thorough analysis can actually generate a savings in the field.

Alternatively, by using your energy analysis to show that your building envelope exceeds the code required minimum by 10% or more, you can access a floor area deduction for any exterior wall thickness that exceeds 8”. For reference, a building with 50’ of street frontage has about 210’ of perimeter wall per floor. For a 16” thick wall, you could deduct 8” and take a deduction of 140 square feet per floor. Over a 10-story building that would give you an extra 1,400 sf and 2 extra apartments.

Another recent example, from an Affordable job we did in the Bronx, involved using our COMcheck to shave a few inches off the lot-line walls and fit another HPD compliant bedroom across the front of the building. For a 9-story building, that meant 9 one-bedrooms became 9 two-bedrooms, and the monthly rental income went up by a couple thousand dollars.

What we have laid out here applies primarily to the exterior envelope, but similar principles apply to mechanical and lighting systems, and a qualified engineer can guide you in the proper direction. We have started to include a line-item on every proposal stating which compliance path we plan to follow and we typically set up the analysis early in design.  In any case, make sure to consult with your design professional early in the process, and get clear on their approach to the energy analysis.

Can't wait for Part II? Stay in-the-know by signing up for our monthly newsletter, "The Hyper Local", and receive insights into the NYC housing market, #zoninghacks to help you navigate the City codes, and more each month right to your email inbox.