Projects / New Homes      Sandwich, MA

Shawme Lake Passive House

"Thank you all for your dedication and efforts in designing and building our passive house! The house is incredibly comfortable, efficient, and beautiful."


  • 2021 PRISM Gold Award - Best High Performance/Energy Efficient Home
  • 2021 PRSIM Silver Award - Best Millwork
  • 2021 BRICC Award - Best Energy Design
  • 2023 BE+ Green Building Showcase Award - Green Home of the Year
  • 2023 PHIUS Passive Projects Design Awards - Source Zero Winner


  • Fine Homebuilding
  • Falmouth Living


As the oldest town on Cape Cod, Sandwich celebrates and perpetuates its historic, namesake architecture. Homes are characterized by simple forms and traditional English styles, adapted over time to the harsh, coastal climate and native resources. New buildings are encouraged to draw upon local heritage for aesthetic inspiration, but embrace advances in building science that impart energy efficiency, enhance occupant comfort, and ensure durability into the future.

Drawn to Sandwich’s idyllic waterways and walking trails, our clients purchased a small but covetable lot hugging Shawme Lake and the town’s Heritage Museums and Gardens. They envisioned building a Passive House with modern appeal, but were faced with complex site restrictions and the historic district’s strict aesthetic guidelines for new construction.

We were asked to reconcile contradicting goals for both form and function by designing a residence that was classic yet contemporary, ambitious in performance yet challenged by its setting.


The property was the last in its neighborhood to be developed, a tight site flanked closely by neighbors, public conservation land to the west, the road to the south, and a wooded lake to the east. It’s triangular shape and sloping topography complicated options for the structure’s footprint, as did the requirement of a south-facing roofline to support a solar array. With consideration given to needs for space, privacy, and Passive-House potential, the home was divided into two angled masses: a trapezoid and an asymmetric pentagon.

To win approval by the historic committee, we visually regularized the irregularly-shaped structure by joining the geometries beneath a straight and sweeping roof plane. Two perpendicular gables disguise the many elevations and cut-ins beneath them and maintain simplicity of form. From the street, the home presents as a single-story residence with modest glazing, mirroring the context of surrounding houses.

With the business in the front settled, we adopted a party-in-the-back quality for the rest of the project. Large banks of high-performance glass run along the more private facades, opening views to the lake and accessing a network of covered and exposed outdoor spaces.

The clients’ modern design sensibilities continue to the interior, where clean lines prevail and non-functional elements are kept to a minimum. Custom millwork throughout the home – including integrated kitchen cabinets with hidden hardware – extends from floor to ceiling to seamlessly conceal storage within the structure. A stately blue marble backsplash, cut from a single slab, finishes the space.

The oldest extant residence in Sandwich is believed to pre-date the 1700s; we hope this practical and elegant instance of mullet architecture will persist just as long and require far less maintenance over its lifetime. The exterior is clad in FSC-certified larch and durable, zero-maintenance cementitious panels designed to endure for more than a century. PHIUS+ 2018 and Source Zero certified, the project also stands to provide lasting comfort for occupants at a minimal cost and without the use of fossil fuels. The building reimagines Cape Cod style, which historically lacks proper insulation, with airtight construction, double-thick walls packed with 12 inches of dense cellulose, and a heat-recovering fresh air ventilation system.


  • Year Completed

  • Cost

  • Gross Floor Area

    3048 sq ft
  • Beds

  • Baths

  • Partners

    The Valle Group
    Casco Bay Engineering
    Brian Laverriere Landscape

Sustainability Achievements


  • Walkable location
  • Sustainable landscape
  • Native plantings
  • Resilient landscape design


  • Uses locally-sourced materials
  • Designed for durability
  • Designed for low maintenance
  • 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


  • Fossil fuel-free building
  • Uses renewable energy systems
  • Uses passive design strategies
  • Net zero
  • Meets Passive House requirements
  • Fresh air ventilation system with heat recovery
  • Super-insulated
  • Triple-glazed windows
  • Electric vehicle charging integration
  • Has achieved Passive House Certification
  • Airtight construction
  • Predicted EUI: 0
  • Actual EUI with PV: -3.1
  • Predicted % Reduction from national average EUI: 106%
  • Windows R-value: 7
  • Walls R-value: 42
  • Roof R-value: 72
  • Slab R-value: 40
  • ACH50: .51
  • HERS: -12