PASSIVE HOUSE NET ZERO LPC . 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

ZERO ENERGY READY . Scandinavia in Stamford

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. 


100 % OFF THE GRID FARMHOUSE . Litchfield County CT

Trillium Architects earned the AIA CT 2016 Chrysalis Award for a continuing commitment to design excellence upon completion of this ambitious project

Created to be an artisan’s home, studio, and small farm, this house was built to be 100% “off the grid”, meaning it is not connected to the electrical grid at all. It utilizes only energy produced on site. This is achieved through a solar PV array with battery collection located on the barn, a wood fired boiler, and a wood burning stove and oven in the kitchen for cooking and a sense of warmth.

The home faces due South for optimal passive solar heat gain, concrete slab and masonry walls act as thermal mass to provide radiant heat into evening hours. The walls are constructed using Durisol Insulated Concrete Form (ICF), of which, 30% are bermed into the Earth, including an integrated root cellar. Natural ventilation is provided by high transom windows, and shading is controlled by exterior and interior curtains. With post and beam framing and pine board paneling in place of standard drywall, the house uses 100% natural and, whenever possible, locally sourced and upcycled materials.

Old and new technology combined make this house super-energy-efficient

Time-tested passive-solar strategies are at the core of this project, but that's only part of the story. Here are some of the features that allow this home to be 100% off the grid:

  • The building envelope is designed to Passive House standards (Air-tightness: <0.6 ACH@ 50 pa)

  • The long axis of the house faces south for optimal passive-solar heat gain

  • High transom windows, overhangs, and exterior curtains optimize passive solar attributes

  • Photovoltaic Electric system

  • Wood Fired Boiler for hot water and back up radiant heat

  • Insulation: Roof - Cellulose R60; Walls - R28; Sub-slab - R56; Windows - R9.8

  • Rainwater collection to provide water for farm animals

Size of project: 2,600 sq. ft. 


PASSIVE HOUSE . Farmhouse Hudson Valley, NY


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


NET ZERO . CT Contemporary Dream Home

This is the second Net Zero home the clients for this Connecticut contemporary commissioned from the architect and builder.  The first house was a 6500 square foot, net zero home in New Canaan designed for re-sale. For this home - their retirement / dream home - they wanted something smaller and more ‘true to their aesthetic’.

They tasked the team with creating 2400 maximum square feet of one story living space floor with the master bedroom,  all to be fully accessible, so they could stay in the house come what may in their retirement years. The lower level became the realm of guest bedrooms for their visiting grown children and the beloved ping pong table. 

The clients are very savvy and monitored the energy use of their previous house meticulously and understood what a real energy efficient wall envelope should look like. They knew they were getting a Tesla and wanted to make sure they had enough PV power on the roof to cover all electric use now and in the future. They knew they wanted a contemporary aesthetic with lots of warm wood beams and brick wall. The result is a perfect house just for them.

They love it so much more than their last house and they feel really good about their significantly reduced carbon footprint.



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