Taft School Residence

Project Subtitle: 

Taft School Residence

Project Description: 

The Taft Residence serves as a home and teaching device, supplying one teacher, and his/her family, with a living residence while offering a learning example for the Taft students of how a high-performance home is designed. This private school was founded in 1890 and had an existing residence demolished to build a high performance home that is the Taft School Residence. This home was designed by Trillium Architects to meet Passive House Institute US Certification requirements, as well as ENERGY STAR v3.1, DOE Zero Energy Ready Home, LEED BD+C Homes v4, WaterSense and EPA Indoor airPLUS program standards. This residence includes a 1,400 square foot conditioned basement area below 2,400 square feet of finished space. There is city water, sewage, and natural gas available nearby underground.

Building Type Summary: 

Single family residence

Other Awards: 

CT Zero Energy Challenge (3rd place), U.S. DOE 2015 Housing Innovation Awards Grand Winner, Residential Award of Honor (CTGBC)

Address: 

59 North Street
Watertown, CT 06795
United States

Lat. / Long.: 

POINT (-73.1213623 41.6055379)

Number of stories: 

2

Conditioned Floor Area: 

3 600

Multiple buildings?: 

Historic?: 

Completion date: 

Friday, April 10, 2015

Site description: 

An existing residence was demolished to build this new residence.

Materials: 

A PV array was installed on the roof to bring site energy consumption to net zero. Used low-VOC sealants, caulks, adhesives, primers and paints. Also used existing granite stones from original house foundation for the steps and stone walls.

HERS Index: 

-14

Annual renewable energy generated: 

-17 160

Power Rating: 

13 100Watts

Subslab assembly: 

R-28 under slab

Slab edge assembly: 

R-20 at slab edge

Foundation wall assembly: 

Inside the solid concrete foundation is 3” closed cell foam behind 2x4 stud walls and cellulose in the cavity.

Above grade wall assembly: 

Double stud walls have 2¼” closed cell foam plus 8½” 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.

Flat attic assembly: 

The attic floor is framed with I joists and serves as the top of the building's air-tight envelope, for it has 24" to 36" of blown denspak cellulose insulation both on top and below the floor. The center of the attic floor is double framed with perpendicular boards, so that the HVAC equipment can be between the ceiling and distribution systems and remain in the envelope.

Space heating - Manufacturer & Model: 

Mitsubishi MXZ0B Multi Split Heat Pump

Space cooling - Manufacturer & Model: 

Mitsubishi MXZ0B Multi Split Heat Pump

Domestic hot water - Manufacturer & Model: 

Stiebel Eltron Accelera 300; 2.73 EF

Ventilation - Manufacturer & Model: 

Zehnder Novus 300

Utility incentives: 

Earned $9,000 through the CT Residential New Construction Program

Ratings: 

DOE Zero Energy Ready Home, Passive House (Passive House Institute US), ENERGY STAR v3.1 certification, LEED BD+C Homes v4 Platinum Certification, Indoor airPLUS, WaterSense labeled home, & Living Building Challenge Petal certification

Published References: 

Special architectural measures: 

Located on a quiet street adjacent to campus the existing, historic home was deconstructed for its efficient replica. Challenged to find high efficiency windows that were historic commission acceptable, the team 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.

Energy Use and Production Documentation: 

Subslab R-value: 

28.00

Slab edge R-value: 

20.00

Foundation wall R-value: 

32.00

Above grade wall R-value: 

55.00

Flat attic R-value: 

86.00

Average window U-factor: 

0.11

Door U-Factor: 

0.11

Site conditions: 

previously developed land

Renewable Energy Sources: 

Renewable energy is generated within the building footprint (e.g. solar PV on the roof)

Summary of enclosure strategy/description: 

The Taft School Residence has a durable, very insulated thermal envelope to create an air-tight, bridge-free space.

Window Description: 

The windows are made of European Eco-clad & uPVC frames are triple glazed with argon filling and two low-E coatings that have a U-value of 0.11. All rough areas around windows are taped to prevent air leakage.

Door Description: 

Similar to the windows, all exterior doors are made of European Eco-clad & uPVC frames are triple glazed with argon filling and two low-E coatings that have a U-value of 0.11. All rough areas around windows are taped to prevent air leakage.

Mechanical Equipment Installation Details and Comments: 

Partially ducted air-source heat pumps provide efficient heating and cooling while a heat-pump water heater with occupancy sensors in the baths delivers immediate hot water.

Number of Bedrooms: 

4

Project Team: 

Architect

Team Member: 

Elizabeth DiSalvo
Builder

Team Member: 

Christopher Trolle
Energy Consultant

Team Member: 

Karla Butterfield

Status: 

Live

Zero Net Energy Definition Used: 

Site Energy Use

Basis of Performance Claim: 

Modeled
Zero Energy Program

Type of Construction: 

New

Renewable Energy System Type(s): 

Photovoltaics

Renewable Energy System Description & Details: 

A 13.1 kW PV system was installed. REM/Rate modeling estimates annual utility costs of about $2,500 without PV and -$990 per year when modeled with PV. However, the building is performing better according to builder Chris Trolle. He claims annual utility costs of $1,500 without running PV due to the efficient features of the home and passive design.

Annual Renewable Energy Generated Data Type: 

Modeled
Measured

Space Heating - Efficiency (e.g., 92 AFUE): 

9.3 HSPF

Space Cooling - Efficiency (e.g., 16 SEER): 

16.5 SEER

Air Changes per hour, CFM50: 

244.00

Submitter Contact Email: 

Submitter Contact Phone Number: 

(203) 857-0200 x206

Project Type: 

Zero Energy

Indoor Environment Description: 

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.

Weight: 

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