Passive House and LEED Platinum Taft School Faculty Housing

The Taft house—one of our most ambitious energy-efficient homes to date—received the following awards and certifications:

And it received:

The project is also:


The Taft School, a boarding school, in Watertown, CT, wanted to build a state-of-the-art green home to support the school’s commitment to faculty housing and environmental stewardship. This is a single family two-story, 3 bedroom, 2.5 bathroom home with detached two-car garage, located in the Historic District. The home is oriented to optimize the use of passive and active solar energy. The energy usage will be monitored by the residents at an integrated iPad screen and by the Environmental Science students in the classroom.


Foundation: 8" solid concrete foundation
wall; 3" closed-cell on interior (R-19); 2x4
stud wall filled with blown cellulose (R-13);
rigid foam at slab perimeter (R-20); rigid
foam under slab (R-38)

Walls: Double walls consisting of two 2x4 walls
set; 3.5" apart; 2" closed-cell spray foam (R-16); 
8.5" dense-pack cellulose (R-32); insulated, coated, 
taped sheathing (R-6); R-55 total assembly

Attic: 24" blown cellulose on attic floor
over 9.5" engineered joists (R-100)

Windows: UPVC and aluminum-clad
wood framing; argon-filled; triple-glazing;
low-e; U=0.09 for north facing windows;
U=0.11 for all other windows; SHGC=0.61
on south, east, and west facing windows
for beneficial heat gain

Air Sealing: 0.6 ACH 50

Ventilation: HRV; MERV 8 filters

HVAC: Air-source heat pump

Hot Water: Heat pump hot water heater

Lighting: 100% LED interior and exterior

Appliances: ENERGY STAR-rated
refrigerator, clothes washer, dishwasher,
and ceiling fans, condensing dryer.

Water Conservation: All EPA WaterSense rated fixtures (except kitchen faucet);
motion-sensing recirculating pump

Solar: 13.1-kW PV

Other: Energy management system;
detached garage; low-VOC

Size of project: 3,891 sq. ft.

Builder: BPC Green Builders

Read the case studies below to learn more about what makes the Taft house a comfortable, sustainable, high-performance home

Bright and Airy Waterfront Home in Stamford CT

Built for a retired couple, this house was designed for single-floor living, with the entire first floor ADA accessible. The upstairs rooms accommodate visiting children and grandchildren, with plenty of bright open spaces for the family to spread out and have fun. Patios, covered porches, and expansive windows wrap around the house, allowing everyone to sit out and enjoy the sea breezes on sunny days, or take in the waterfront view from the comfort of the sun room or living room when the weather isn’t as warm. Trillium Architects took cues from the family’s Scandinavian heritage and incorporated solid wood, natural light, clean lines, and bright, soothing colors throughout the house to make it truly feel like home. 


Hudson Valley, NY - Passive House Certified Farmhouse - LEED Platinum


Nestled into a wooded lot in Dutchess County, NY, this super-insulated house gets half of its heat from the sun. And over the course of the year its roof-mounted solar PV array produces more electricity than the house consumes. The project included lots of locally-sourced and low-environmental-impact materials, including exterior trim made with recycled fly ash and oak flooring milled from trees felled right on the property. A rainwater collection system and root cellar help the homeowners to sustainably grow and store their own vegetables.


  • Roof: 16-in. TJI framing with 12-in. dense-pack cellulose/4-in. closed-cell spray foam (R-66 combined)

  • Walls: Double-stud walls with 9-in. dense-pack cellulose/3-in. closed-cell spray foam (R-48 combined)

  • Foundation: 3.5-in. mineral wool insulation/3-in. closed-cell spray foam (R-30 combined)

  • Slab: 8-in. EPS IX rigid insulation (R-40)

  • Windows: Triple-glazed, aluminum-clad, wood frame (013 U-value)

  • HVAC: Ducted air-source heat pump; ducted energy-recovery ventilator (ERV)

  • Water: Heat pump hybrid water heater

  • Blower-door test: 0.43 ACH50

  • 11.4kw solar PV array (with solar, home is net energy producer)

  • House orientation optimized for solar heat gain

  • Window layout planned to capture approximately 50% of energy needed for heating

  • Energy-efficient LED lighting throughout the house

Builder: BPC Green Builders

Articles, awards, and certifications

U.S. Department of Energy: Zero Energy Challenge - Housing Innovations Award Winner

Passive House Institute US: PHIUS+ Source Zero certification (i.e. generates as much energy as it uses)

USGBC: LEED Platinum certification

CTGBC: 2018 Passive House Award of Merit

BPC Green Builders: Description and specifications for the project


Traditional New LEED Gold Home in Rowayton, CT  

This LEED Gold certified home won the CT Green Building Council Residential Award of Merit, 2013. The client and project team shared a goal to create a beautiful, well-crafted, and extremely sustainable home. Oriented to capture pond and stream views, the interior is flexibly laid out for entertaining, while feeling intimate for a family of four. 


  • Blower door test: 1.0 ACH @ 50 pa
  • Ground-source heat pump HVAC system
  • HERS Score: 48
  • Super-insulated and air-sealed envelope  
  • All LED lights; all EnergyStar appliances
  • FSC-certified wood throughout
  • Automated, remote-controlled lighting, heating/cooling, security
  • High-efficiency fireplace for back-up heating
  • Ceiling fans reduce need for air conditioning
  • Rainwater collection system feeds the irrigation system
  • All no- or low-VOC finishes
  • Indigenous landscaping
  • Water-saving fixtures
  • Project Size: 3,548 sq.ft.

Builder: BPC Green Builders

Articles, Awards, and Certifications

CT Green Building Council: LEED Gold certification and Residential Award of Merit, 2013

BPC Green Builders: Description and specifications for the project


New Canaan Net Zero Home Produces More Energy Than It Uses

An empty-nester couple sought to build an expansive new home that incorporated a flexible accessory apartment to accomodate tenants or aging parents.  Thanks to the owners’ particular passion for energy-efficient systems, the home is Net Zero rated: it actually produces more energy than it consumes.


  • 19 kW Photo-voltaic electric system

  • Roofs optimized for PV arrays

  • Evacuated-tube solar hot water system

  • Heat pump/mini-split heating and cooling

  • High-efficiency gas fireplace insert for backup heat

  • 2 ERVs (energy recovery ventilators)

  • Blower door test: <0.7 ACH@ 50 pa

  • Wall insulation: Cellulose and rigid foam board wrap R28

  • Sub-slab insulation: R28

  • Windows: R9.8

  • Roof insulation: Cellulose R60

  • Project size: 6,000 sq.ft.

Additional information

BPC Green Builders: Description and specifications for the project


AWARD WINNER! ~ 2016 CTGBC Residential Award of Merit~Net Zero ~ Ridgefield

Ridgefield Super Energy Efficient Lake House

A retired couple sought a compact, modern home that would optimize their beautiful lakeside site. Trillium Architects designed their home in a clean-lined, minimalist style which fit well with the couple’s budget. Making the most of the site, the home offers outdoor spaces on two levels, with large glazed openings that blur the distinction between indoors and outdoors, keeping the focus on the spectacular natural surroundings.


  • HERS Index: 28
  • Floors: R46; Basement: R54; Walls: R24.2; Roof: R46
  • Blower door test: 1.0 ACH @ 50 pa
  • Ducted mini-splits for heating and cooling
  • High-efficiency gas fireplace insert
  • ERV (Energy Recovery Ventilator) for whole-house ventilation
  • Untreated, low-maintenance cedar siding over rainscreen
  • Re-used existing foundation and stone chimney
  • Preserved existing trees
  • Size of project: 2100 sq.ft.