Projects / New Homes      Durham, NH

Spark Side

Durham, NH lost power for about two days right before Christmas and we got a great real world test of the envelope. On evening #1, after running just the main floor mini-split during the day set to 68 degrees, we turned off the generator and went to bed. With 8+ hours of single digit temps overnight and no passive solar input, we woke up to the house at 62 degrees. So impressive.”


  • New Hampshire Home Design Awards: Net Zero Winner


  • Wall Street Journal
  • NH Home Magazine


The clients wanted a Passive House, that they knew. They purchased a wooded, 2.8-acre lot with an old stone wall, remnants of a farmstead. Clearly somebody knew what they were doing with this land once. However energy efficiency then wasn’t what it is now. We’d need to gather the sun in from a direction almost 90 degrees off of the primary drainage slope, and provide a new entrance to the house that afforded privacy to the owners. They were looking for something that connected them directly with the outdoors – where they and their dog Vader spent much of their time regardless of season – and that echoed the traditional forms of the region yet lived like a state-of-the-art, net zero energy home.


We created a fossil-fuel free structure, simple and classic in form, with a detached, barn-like garage and connecting breezeway. Approaching from the back end of the property, the house emerges solid and modest. On the farmhouse porch, sunlight filters through a trellised cutout on the roof to dance across a massive boulder that sits beneath it. Harvested from the site and rolled into place, the monolith pays homage to the old stone wall it once served as a cornerstone for.

Spark Side’s glassy entryway provides a hint of the modern interior beyond, where oversized, high-performance windows flood the double-height kitchen, dining, and living spaces with light and passive heat. In similar fashion to the slatted exterior breezeway, the open staircase offers a glimpse through the residence, past the kitchen and living room to the full-width screen porch at the rear of the home. 

We conducted a Biophilic Charette with the owners to capture and recreate their favorite moments spent outdoors. As avid adventurers, they were immediately drawn to the idea of incorporating “risk and peril” in the design. We were able to evoke a sense of precariousness with a cantilevered loft extension on the second floor. Supported by just 2.5 inches of specially laminated structural wood, the loft jets into the double-height living and dining room with structural tenuity, evoking a bit of the same rush felt when standing on a cliff’s edge and peering down. A large window inside the second-floor primary suite overlooks the dining room, accentuating the vibe.

The south side of the building is as open as the north side is protected, with most of the home’s windows concentrated on the facade where they will work the best. The ample, high-performance, large-paned glass brings in practically all of the heat needed even in winter, while 12-inch thick, superinsulated walls, floor, and roof make sure the heat stays in. Spark Side’s energy use is reduced by about 90% from a code-built home, and is achieving Net Zero Energy on an annual basis. All-electric heat pumps provide comfort, tempering the space when needed, while an energy recovery ventilator provides fresh air.


  • Year Completed

  • Cost

  • Gross Floor Area

    4370 sq ft
  • Conditioned Floor Area

    2921 sq ft
  • Beds

  • Baths

  • Partners

    Haven Hill Builders
    Soren Deniord Design Studio
    Trillium Engineering Group

Sustainability Achievements


  • Native plantings


  • Embodied Carbon: 146 gCO₂e/m²
  • Designed for durability
  • Designed for low maintenance
  • Designed for minimal embodied energy
  • Low global warming potential insulation


  • Optimized for daylighting
  • Fresh air ventilation system for indoor air quality
  • Visual connection to the outdoors
  • Low-VOC finishes
  • Formaldehyde-free building


  • Low-flow fixtures
  • Heat pump water heater


  • Certified Passive House
  • Net Zero Energy
  • Fossil-Fuel Free Building
  • Benchmark EUI: 45.7
  • Predicted EUI: 0
  • Actual EUI: 0
  • % Reduction from Benchmark EUI: 100%
  • Type and Size of Renewable Energy Systems: 12.4 KW PV array
  • ACH50: 0.63
  • Airtightness of envelope: 0.04 cfm50/ft²
  • HERS Score: -10