2017 High-performing homes showcase: Cozy cabin with nearly unparalleled performance

This is just one of a series of high-performing homes highlighted in the spring 2017 issue of GHM Homes. See the rest here.

Photo: ncob photo

Photo: ncob photo

Harpswell, Maine

THIS OCEANFRONT HOME was designed by George Penniman, principal at George Penniman Architects, along with his wife and landscape architect, Anne Penniman. George was inspired to build a Passive House after training as a Certified Passive House Designer with the Passive House Academy in Brooklyn, NY & Ireland.

The house was built on helical piers, affording a very light environmental footprint. There is no slab or basement, eliminating the need for heavy site work. Utilities run underground and up through an insulated pod which begins 4’ below grade and continues up through the heavily insulated floor system.

All finish materials were sourced as locally as possible. The exterior white cedar and hemlock, the pine that was used on the interior walls and the ash floors were all sourced from Maine forests. Additionally, stone in the entry and the tile backsplash is Englishman’s Bay granite quarried in Maine. Other materials chosen for their sustainable and non-toxic qualities include PaperStone countertops, Vermont Natural floor stain and finish, low VOC paints, and plant-based oil for natural wood wall finish.

The house was designed to accommodate a future addition.

Why we like it: This home is excellent proof that pre-fab construction can more than match the performance of onsite custom construction. This home is built using extremely tight vaporopen assembly panels (including the floor) and erected in place on site. The all-wood triple pane windows add to its performance and New England cabin charm. The super insulated structure is then founded using helical piers that lift it off grade. The result is a modern, cozy cabin that has nearly unparalleled energy performance.


Pre-Certified Passive House. Heating demand - 4.1kBtu/sq ft per year. Primary Energy demand- 36.8 kBtu/sq ft. $400 Estimated annual cost for heat and electricity.


Foundation—Built on helical piers. 24” TJIs with dense pack cellulose under floor R-81. Walls—Panelized 117/8” TJI (wood I-joist) studs combined with 2x4 wall construction filled with dense packed cellulose insulation, covered with mineral wool R-55. Roof—cathedral truss rafters filled with dense packed cellulose R-111. Windows—Triple pane European tilt-turn. Airtightness—ACH50 – 0.4


Heating and Cooling—ductless mini-split heat pump. Ventilation—Zehnder ERV.




1,300 sq ft


  • DESIGNER: George Penniman Architects / Anne Penniman Associates

  • BUILDER: Ecocor High Performance Buildings

  • RENEWABLES: solar planned for future

  • ENERGY/PERFORMANCE CONSULTANT: Ecocor High Performance Buildings


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This article was reprinted from the spring 2017 issue of Green & Healthy Maine Homes. Subscribe today!