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Taft Faculty House: Award Winning Energy Efficiency

Market: Residential - Education
Type: Faculty Housing
Location: Watertown, CT
Developer/Owner: BPC Green Builders
Architect: Trillium Architects
Project Services: Green Building Certification, Sustainability Consulting, Third Party Verification and Testing
Building Size: 3,891 sf
Certifications: ENERGY STAR, DOE Building America Partner, EPA Indoor air PLUS, LEED for Homes, Passive House (PHIUS)

The Taft School faculty home designed by Trillium Architects serves as a high performance residence and learning lab for students. Constructed by sustainability industry veterans, BPC Green Builders, the home achieved a HERS 33 excluding PV and with the 13.1 kW the HERS index is -14.

Located on a quiet street adjacent to campus the existing, the former historic home was demolished for to make way for its energy efficient replica. The team was challenged to find high efficiency windows that would be acceptable to the Historic Commission, so they installed Klearwall awnings or casements over fixed glass (to mimic double hungs) with simulated divided lites (u-values as low as 0.13). A high solar heat gain coefficient (0.58) facilitates the passive solar gain for winter months, while well designed overhangs and pergola shade summer sun.

Double stud walls have 2” closed cell foam plus 8” dense pack cellulose for a R-49 cavity. The exterior sheathing is R-6.6 Zip Wall System with taped seams to create the continuous air barrier. Inside the solid concrete foundation is 3” closed cell foam behind 2×4 stud walls and R-32 cellulose in the cavity. Prefabricated TJI joists frame the attic floor, an insulated “room” houses the heat recovery ventilator and ductwork, and blown in cellulose blankets it all in R-86.

The house tested 0.6ACH50 proving the effectiveness of its air-tight envelope and attention to air sealing. Heating and cooling is provided by efficient air source heat pumps (9.2 HSPF, 16.5 SEER) and delivered by short duct runs which tested extremely tight. A heat pump water heater provides domestic hot water and an on-demand switch, with an occupancy sensor at each bath, ensures hot water is delivered fast and efficiently.

Low-flow fixtures are WaterSense certified, appliances are Energy Star labeled, and all LED lighting. A Zehnder Novus 300 (93.3% efficient) HRV supplies 112 cfm of continuous fresh air ventilation; using only 32 watts of power and runs quietly. The homeowners control the mechanical ventilation through the intuitive wall-mounted control pad to shut off or increase the ventilation.

Chemicals and contaminants were reduced by using low VOC and GreenGuard certified sealants, adhesives, primers, and paints. A walk-off mat at the side entry and hardwood floors help control dirt and dust. The granite front steps were salvaged and local stone used for the patio and stone walls. Storm water runoff from the roof, patio, and driveway is managed by the rain garden and native landscaping is low maintenance.

Taft School Director of Environmental Stewardship, Carly Borken has used the design and construction process as a teaching tool for her science classes. With access to the home monitoring system, her students can virtually access the residents’ consumption. This project won Third Place in the 2014 Connecticut Zero Energy Home Challenge.

Awards

  • USGBC LEED Homes Award Winner
  • 2015 Housing Innovation Awards Grand Winner
  • CTGBC Residential Award of Honor
  • CT Zero Energy Challenge Award Winner