2013 Challenge Participant:

BPC Green Builders

Applicant: Mike Trolle

Project Address: Danbury, CT

Bdrms./Sq. Footage: TBD

Builder Website: www.bpcgreenbuilders.com

Project Overview Project Specifications Project Team Project Photos
The BPC Green Builders project in Danbury, CT.


1,600sf, 3 bedrooms


Certification Programs:

PHIUS, Passive House Institute US

EPA, ENERGY STAR Certfied Homes (preliminary HERS Index 41, no renewables)

DOE, Building America Partner

EPA, Indoor air PLUS


Building Site

  • Tapered lot on a hill in a lake community
  • Existing residence was dismantled and new home built on existing foundation.
  • There is no natural gas available on site; fuel sources changed from oil to electric and propane


House Envelope

  • 12” expanded polystyrene (EPS) foam board (R-58) under new frost-protected shallow slab foundation, and 6” EPS (R29) applied to exterior of the shallow slab walls.
  • 2x6 wall construction with 5-1/2” of blown cellulose (R20), plus two layers, 5-1/2” of polyisocyanurate foam board (R37)
  • Further to the reduction of thermal bridging there are two stud corners, insulated headers, and interior wall to exterior wall intersections left open to receive insulation
  • To reduce air infiltration all sheathing joints are taped as are rough openings around doors and windows. The entire outer envelope of the house has been sheathed with plywood with taped joints.
  • Windows and exterior doors feature PVC frames and triple glazing with argon gas fill and two low-E coatings with U-value of 0.12  Skylights are clad wood with similar glazing and U-value of 0.14
  • Blown cellulose fills the 18” open-web roof trusses (R68).
  • 7.25” of mineral wool insulation (R29) insulates the floor joists over the existing unconditioned basement, with 3” of polyisocyanurate foam board (R21) underneath.


HVAC Systems

  • The majority of the heating load is satisfied by internal and solar heat gains.  The south wall of the house has 95sf of glazing with a 0.61SHGC that admits solar heat during the cold months that will be absorbed by the heavily insulated shallow slab foundation.
  • The house is heated and cooled by a one-ton, air-source heat pump.  A ducted fan moves conditioned air around the house from the Great Room where the heat pump is located.  
  • Ventilation is provided by an energy recovery ventilator (ERV) which draws exhaust air from the bathrooms (and ventilates them) while simultaneously providing fresh air to the entire house.
  • A high efficiency, condensing, tankless, propane-fired hot water heater creates hot water for domestic use.  


Plumbing & Electrical

  • The hot water piping is insulated with R-3 insulation
  • Low-flow faucets and toilets will be used throughout the home to conserve water
  • The refrigerator, dishwasher, & clothes washer will all be Energy Star rated.  The dryer will be a condensing unit that does not require an exterior vent.
  • Daylight will be the primary source of light. The electric lighting will be a mixture of fluorescent and LED fixtures;  standard fixtures will have CFL or LED bulbs


Additional “Green” Features in the Home

  • Low VOC sealants, caulks, adhesives, primers, and paints
  • Existing bluestone from the original house and natural stone from the excavation work has been used for walls and walkways.
  • Roof overhang shades the south wall from Summer sun
  • Re-used w/w carpeting
  • Re-used concrete block foundation
  • Re-used some paneling and interior doors
  • Accommodations for future PV arrays on roof
  • Green demolition: full abatement of asbestos, lead. Off-site separation of clean debris
Website by: 505 Creative Services, Guilford CT  |  www.505Creative.com
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