Any building in New York City should be allowed to generate solar energy on its rooftop. Buildings should be rewarded, not penalized, for adding insulation to reduce their energy use and carbon emissions. It’s a great addition to the urban landscape when green roofs and urban farms sprout on top of our buildings.
No-brainers, right? Well, until yesterday, New York City’s zoning inadvertently discouraged or prevented all these green building strategies. But now, our zoning has gone green.
At the Department of City Planning, we learned from building owners, developers, architects, and engineers that zoning regulations written in the mid-20th century were preventing our buildings from joining us in the 21st century. Buildings could add air conditioning equipment on their rooftops, but not photovoltaic panels to generate clean, renewable energy, or the planting bed for a green roof. An old-fashioned awning could be used to shade a window, but modern sun control devices couldn’t hang over a yard. Adding continuous external insulation to dramatically improve energy efficiency could push a building over limits on floor area.
So the Department, under the leadership of Commissioner Amanda Burden, embarked upon the most comprehensive effort in any U.S. city to sweep aside zoning impediments to green buildings. The product of this effort, the Zone Green text amendment, was approved yesterday by the City Council. Developers and building owners now have more choices for the investments they can make to save energy, save money and improve the quality of our environment.
Before Zone Green, developers were confronted with a tradeoff between thicker, energy-efficient walls and usable interior space, because floor area was always measured to the outer edge of the exterior wall. Now, new buildings that exceed the requirements of the New York City Energy Conservation Code can deduct a portion of the thickness of exterior walls from floor area, leveling the playing field for highly energy-efficient construction.
The zoning changes promote not only new green buildings, but also retrofits of existing buildings. Existing buildings can add up to eight inches of wall thickness for the purposes of external insulation, without violating limitations on floor area or requirements for yards or other open areas. Features like solar panels, recreational decks, and sun control devices can be added to new or existing buildings. Complete information about the zoning changes is available on DCP’s website.
Additional legislation at the City and State level will extend the reach and effectiveness of Zone Green. On Monday, the Council also approved legislation enabling sun control devices to project over streets and sidewalks to the same 2-foot-6-inch dimension permitted for these devices within the property line under the zoning. In addition, the State Senate has approved legislation that would modify the Multiple Dwelling Law to enable pre-1961 buildings to make use of the external insulation allowances of Zone Green, and a companion bill has been introduced in the Assembly.
Thanks are due to Urban Green Council and members of the Green Codes Task Force, whose expertise and support have been indispensable to the Zone Green project from its early development through public review. This collaborative effort will yield benefits for years to come, helping make New York a greener, healthier city.
For more details on Zone Green, hear Howard Slatkin speak on June 12th.
Cheers to UGC and NYC for bringing the Zoning Code into a smarter, greener 21st Century. But cheers also go to visionaries who were the first to advocate for green zoning http://bit.ly/tcJ2i3
And next, let’s hope this 2012 achievement will be the first and not the last step in retrofitting the City’s powerful zoning rules
Great stuff, but the general perception about thick walls being the most energy efficient is inaccurate. In mass walls, a key driver for energy efficiency is not the thickness of the wall, but the location of the insulation within the wall, as is recognized by placing the insulation exterior to the wall. Thus, a twelve inch NRG insulated concrete block wall(steady state R-value of R-12) can thermally outperform a conventional twenty inch wall that has ten inches of concrete exterior, and ten inches of EPS at R-5 per inch interior (R-54). The NRG wall is just a single (wythe) block which has a continuous layer of EPS that provides a complete separation between the interior and exterior block faces.This is known as insulated thermal mass, which is recognized as the most energy efficient insulation configuration for mass walls in the Advanced Energy Design Guides co-produced by US Green Building Council, US DOE, ASHRAE, and the AIA.
Education is the key, as are accurate energy modeling programs. One such program, eQuest, with thousands of users, has been shown to be inaccurate when modeling different insulation configurations within mass walls. Imagine the life cycle costs of thousands of designers making energy inefficient decisions based on bad information. It is happening right now, and it is a darn shame.