The DUMBO townhouses are five contemporary four bedroom, three bath townhouses with private parking, a garden and a roof terrace. These energy efficient townhouses were designed and built using passive house standards making them very energy efficient. Acting as the architect, contractor, developer and broker for the project Alloy identified that the townhouse program was missing from the neighborhood. While a large condominium tower was an ‘as of right’ option, the team opted to pursue half the development potential. This critical decision lowered construction costs creating efficient townhouses for sale.
Sited within the Landmark District, the team was sensitive to the industrial warehouse context which includes the City’s first reinforced concrete buildings. The facade is clad with tensile Ductal concrete panels, a contemporary concrete technology which compliments the tone and texture of the neighboring buildings and allows the concrete to be cast to delicate proportions. This economically viable combination created a contextually sensitive and beautiful addition to the built environment.
The buildings historical and acoustical contexts were pivotal in defining the projects sustainable design and building performance goals. DUMBO Townhouses were subject to oversight by New York City’s Office of Environmental Remediation for both sound and air quality because of the industrial history of the site and its proximity to the overhead subways that traverse the Manhattan Bridge. The acoustically brutal environment necessitated building techniques which are consistent with passive building technologies that result in the highest of standards for building performance ultimately enabling the design team to establish the following goals:
• Townhouses shall be provided with a minimum 35dB(A) of window wall attenuation to maintain an interior noise level of 45dB(A) or less, with windows closed, and shall provide an alternate means of ventilation.
• Reduce heating energy demand by more than 75% by building a continuous air and thermal barrier and using mechanical ventilation with heat recovery.
• Energy consumption shall be limited to half that of similar new construction home in NY.
• Provide thermal comfort that meets ASHRAE Standard 55 with zoned temperature control.
• Provide minimum wait time for domestic hot water through efficient centralized distribution.
The DUMBO Townhouses employ passive building technologies as the primary strategy for reducing energy and carbon consumption. ASHRAE Standard 55 establishes physical parameters for good thermal comfort which include patterns of air temperature, surface temperature, air motion (draft), and humidity. Air and surface temperature are primarily controlled through a continuous thermal and air barrier including continuous exterior insulation and triple glazed windows with insulated frames. This passive approach is more effective at keeping interior surfaces and air at a uniform temperature than any active heating or cooling system and as a result the key approach to energy savings at a reasonable cost by simply reducing the size of mechanical systems.
Additional strategies employed to limit energy consumption included the exclusive use of fluorescent and LED lighting, Energy Star rated appliances, and the use of a centrally located directly vented, condensing- gas fired hot water heater.
