Solar and Green Roofs Now Required for New Construction in NYC
Nov 15, 2019
by EmPower Solar
NEW YORK CITY BUILDINGS MUST INCLUDE GREEN ROOFS OR SOLAR PANEL SYSTEMS
Following in the footsteps of California, New York City now requires sustainable roofs for new construction. As part of The Climate Mobilization Act, builders must incorporate green roofs or solar panel systems starting today, November 15th. This shift falls in line with NYC’s Green New Deal goals to have one of the most sustainable skylines in the world.
Local laws 92 and 94 require that all new buildings in NYC add either a green roof or a solar panel system. The law also applies to some existing buildings that undergo substantial changes. Builders and homeowners can choose between a green roof or a solar system based on their own preferences. Nonetheless, varying site conditions can be deciding factors such as roof pitch, shade, and energy needs, amongst others. Buildings must install green roofs if solar is not feasible, and vice versa.
There are exceptions, however. A home in the shade would count as an “unfavorable site condition” for solar, and then would default to a green roof. Most green roofs can do fine in shaded environments. If it is a steep roof in the shade, then neither would be required.
Buildings must cover all available roof area in solar and/or green roofs. When it comes to solar, there are building and fire codes that can restrict systems from covering 100% of roof space. So “all available” roof space may be smaller than expected after code restrictions are met. If a building can not accommodate at least 4kW of solar, that would also qualify as an “unfavorable site condition” and solar would not be required. A green roof would then be explored instead. For any roofs that cannot accommodate neither solar or a green roof, “Cool Roof” standards are still required.
This is a huge win for the environment and comes at great benefit to the occupant or end user of the building. Homeowners buying new construction stand to save tens of thousands of dollars in electric bill savings and in most cases can finance the cost of the solar system on the mortgage of the home.
To help builders understand the special requirements needed to site at least 4kW of solar, here are a few examples below. It’s important to note that a 4kW is the minimum system size but the average solar system size for a single family home in NYC is closer to 7kW on average.
How much square footage is required to install a 4kW (minimum size) system in NYC?
Depending on the panel type and efficiency, a 4kW system could require between 10 and 14 solar panels.
Using the highest efficiency panels available — a 10-panel solar system using SunPower 400W panels, would require approximately 200 square feet. Doing two rows of 5, a system would be 12.03 x 16.65 ft. *Note that SunPower 400W panels require a 240 service connection and are not currently compatible in most of New York City which has mostly 208 service. Exceptions include most of the Rockaways and Staten Island.
Alternatively, a 327W SunPower solar system would need 13 panels to get to 4kW (4.25kW). This would take up 227 sq. square feet. (approx. 15×3 x 17.15 ft.)
How much does a 4kW (minimum size) solar system cost in NYC?
The net cost for a 4kW system in NYC couldrange from $6,000 to $7,000 after solar incentives.
How much money would a 4kW system in NYC save the customer?
This would depend on the pitch and orientation of the building. A southern facing home with a 30-degree pitch would produce 4,500 kWh per year, saving them about $108 per month. This system would pay for itself in approximately 4 years in NYC.
How can I learn more fast?
This topic will be covered in detail by EmPower Solar engineering staff during a webinar on Wednesday, December 11th at 12:00pm. To RSVP for the webinar, please email Tara at email@example.com.
EmPower Solar designers and engineers are standing by to provide support and assistance to any builder / architect / engineer with questions on this matter. Please email Tara at firstname.lastname@example.org for additional information.
ADDITIONAL RESOURCES AVAILABLE
- Learn how to design “solar ready”
- NYC Buildings Bulletin: Requirements for new and existing buildings under Local Laws 92 and 94
- NYC Solar and Green Roofs Local Laws 92 & 94 – Full Bill