Sun, sea, and family gatherings draw 20-plus lucky folks to this striking home overlooking Cape Cod Bay. Those appealing elements also presented the biggest challenges for architect Stephanie Horowitz and designer Ben Uyeda of ZeroEnergy Design. “Extreme fluctuation in occupancy was the starting point for our entire design,” Horowitz explains. “The house serves as a year-round weekend home for the two owners and a summer retreat for their entire family.”

The team used spatial separation and flexible mechanical zoning to create the home’s duality. Architecturally, a stand-alone foyer pushes apart the plan’s two distinct volumes and provides a physical barrier that allows the six-bedroom “sleeping bar” to be shut down most of the year. The foyer also offers immediate ocean access, fulfilling one of the owners’ requests to be able to go outside as soon as they arrived, says Horowitz.

Opposite the sleeping spaces, a roomy kitchen (one family member is a chef) flows into an airy living room connected to the bay through a soaring glass wall. This west-facing view presented another challenge to the team’s zero-energy goals. Glass with a low heat gain coefficient mostly saved the day, coupled with a well-insulated envelope that thermally and mechanically offsets the gains. Although the sun’s rays are an issue for keeping the house cool, they also provide most of the energy to do just that. And where 11.7 kW of solar panels leave off, a geothermal HVAC unit picks up. An energy management appliance integrates those renewable resources into the grid and maximizes energy efficiency.

The jury was impressed that despite its size, the house presents a modest profile and generates nearly all of its own power. Marveled one juror: “To be able to create those spectacular views and still have a HERS rating of 33 is incredible.”

Windows: Arcadia Architectural Products / Siding: Cedar / Roofing: Rheinzink / Decking: FSC-certified Ipe / Insulation: Icynene / Appliances: Wolf; Sub-Zero; Miele / Countertops: Caesarstone / Kitchen Faucets: Franke / Bath Faucets: Kohler / Toilets: Kohler / Flooring: Bamboo / Paint: Benjamin Moore / Interior Lighting: Translite Sonoma; XAL; Niche Modern / Exterior Lighting: Bega; B-K Lighting / HVAC: WaterFurnace; Rheem / Alternative Energy: Evergreen Solar (PV); Solectria (Inverter) / Energy Management: Gridpoint

Click here to see all 2010 EHDA winners.