The R-951 Residence is a multifamily building with 3 new condominium units developed for sale. 

Certified under the Passive House standard, the super-insulated 5600SF building, designed by Paul Castrucci Architect, serves as a model for energy efficiency, excellent indoor air quality, and superior thermal comfort. Passive House consulting and mechanical design by ZeroEnergy Design.

Goals.  The developer targeted Passive House certification and net zero capable performance as a market differentiator, successfully selling two of the units before construction was even complete.

Solution.  The resulting building with three dwelling units includes a high performance building enclosure, design for passive solar gain, very high efficiency mechanical systems, and grid-tied photovoltaics. These performance attributes helped contribute to both media and buyer appeal.

Enclosure.  The super-insulated air tight building enclosure includes an insulated concrete form wall system that provides continuous insulation yielding an R-50. An R-50 roof assembly combines mineral wool in the cavity and 5” continuous rigid insulation on top of the roof deck. R-20 is under the concrete floor slab with R-33 on the foundation walls, paired with building details to mitigate all thermal bridging. High performance U-0.14 triple pane windows/doors offer a SHGC-glass of 0.50 to capture the sun's energy. Particular care was paid to maintaining a continuous air barrier, yielding a final infiltration rate of only 0.56ACH50.

Systems.  Ducted air source heat pumps provide space conditioning, including heating, cooling, and dehumidifcation. A Zehnder Comfoair ERV completes the package with highly efficient ventilation and energy recovery. Domestic hot water is supplied in each unit by a heat pump hot water heater. 

Renewables.  On the roof a grid tied 4.5kW photovoltaic system for each unit turns the electric meter backwards to offset energy consumption.





- Passive House Consulting

- Mechanical Design


Certified Passive House


New York Passive House 2015
iPHA Database
2016 Building Brooklyn Award
2015 AIA COTE Award
NYSERDA Trailblazer Award 2015
PHIUS Multifamily Building Award


pEUI: 10.2kBtu/sf/yr
Air Leakage: 0.56ACH50
Better Than Code: 80%
Heat Demand  4.75 kBTU/(ft2yr)
Air Tightness  0.56 ACH50
Primary Energy  33.3 kBTU/(ft2yr)
Cooling Demand  3.40 kBTU/(ft2yr)
Heat Load  3.40 kBTU/(ft2)
Cooling Load  2.74 kBTU/(ft2)


ICF Walls
Steel/Concrete roof  
Steel/Concrete basement foundation
U Value: 0.14
Mineral wool, EPS, and polyiso
R20 Slab
R50 Above Grade Walls
R33 Below Grade Walls
R50 Roof


Ducted air source heat pump (2.5 COP)
ERV (84% efficiency, 0.49 W/cfm)
Hot Water
Heat Pump Hot Water Heaters


Paul Castrucci Architect
Architecture, Visualizations, Photos
ZeroEnergy Design
Passive House Consultant
Mechanical Designer
Yaro Windows
Windows and Doors