Award Winning, Custom New Homes, Energy Star Homes, Passive House, Zero Energy Ready Homes

Cottage in the Woods

passive house in CT

This three bedroom house was built on the 1953 foundation of a tiny cottage in a lake community for one of the owners and founder of BPC Green Builders.  It was designed to use both space and energy with maximum efficiency with secluded views of a rocky, wooded hillside.  Open-style layout with large glass areas facing to the rear for free heat, natural light, and views.

This was the first house in CT to earn PHIUS Passive House certification.  PHIUS is the US offshoot of the European Passive House program.  Certification signifies exceptional energy efficiency.  Energy use is being monitored by the US DOE.  About half of the energy needed to heat the home is provided by the sun for free.

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Special Features

  • Open concept living/dining/kitchen area
  • Cathedral ceiling in main living area
  • Detached garage
  • Extensive use of stone from site in landscaping

Green Building Approaches

  • Rear of house faces solar south to capture winter heat and is ready for PV panels
  • Shallow frost-protected foundation with 12” of rigid foam insulation under the slab
  • 2×6 wall framing with 24” spacing, insulated with cellulose
  • Exterior walls wrapped with 5-1/2” of rigid foam insulation to eliminate thermal bridging
  • 18” roof trusses filled with cellulose, and small attic with 24” of cellulose
  • Acrylic sheathing tapes used to achieve exceptional air-tightness of 0.46ACH50
  • European triple-glazed windows with u-values of 0.13 (roughly R-8)
  • Fiber cement siding installed over ¾” drainage plane
  • Small, wall-hung, air-source heat pump heats and cools the entire house
  • No central heating or cooling required
  • Heating and cooling for the first year cost $337.
  • Condensing, propane, tankless water heater uses 5-10 gallons/month
  • Energy recovery ventilation

  • Housing Innovation Award, 2014 – Department of Energy (article)
  • Zero Energy Challenge winner for lowest HERS score without PV – CT Clean Energy Fund: (video)
  • Subject of Energy Design Update feature article (part 1 and part 2)
Project Year
HERS Score
Type of Home
Project Size
1,650 sf