2006-2008

The Residence 4 is a 2,000 square-foot, 3-bedroom/2-bath single-family residence on the mid-coast of Maine. The overarching goal of the project was to build the highest-performing green home within a moderate budget ($220,000). At a cost of $110 per square foot, the Tucker/Zegel home is an incredible example of cost-effective green building.

Belfast is a cold climate (7,400 heating degree days) but sees sunny skies almost 50% of the time in winter. The home sits on a 3.9-acre rural site with full southern exposure. Therefore the primary heating strategy for the house is passive solar coupled with a super-insulated thermal envelope. After thorough energy modeling and research into the most cost-effective glazing and shell materials it was determined that south-facing windows would be fixed, triple-glazed, high solar heat-gain units with fiberglass frames. Walls were constructed of 2x6 studs and 4 ½” structural insulated panels made with urethane foam, manufactured locally. Overall R value for the wall system is 44. The roof is a shallow pitch hip roof, insulated with blown cellulose to R 50. The foundation of the house is a frost-protected, insulated slab-on-grade which was polished and finished as the finish floor. Other interior finishes are simple and straightforward to save cost: cabinetry is solid maple, finish floor on the second floor is local pine. All materials were chosen for their combination of durability, local sourcing, low toxicity, and reasonable cost. The house is also equipped with a heat recovery ventilator to save energy and ensure a healthy indoor environment.

For the 2008-2009 heating season the results were fantastic: the radiant heating system embedded in the floor never came on and indoor temperature averaged 64 degrees. The small amount of supplemental heat required came from the burning of scrap construction lumber in a small woodstove. The house has a solar-thermal system for domestic hot water which supplied approximately 60% of the demand. The fuel demand for the last 15-month period averaged 10.5 gallons of propane per month and supplied a back-up boiler and kitchen range. Electric usage is only for appliances and lighting.

At $110 per square foot, the Residence 1 proves that truly green construction can be realized for a cost the average person can afford. The additional costs for upgrades to achieve the energy performance amounted to approximately 10% of project costs and will be returned in energy savings in only a few years. The attached spreadsheet outlines the contracted pricing for the project which includes septic system and well but excludes interior painting which was handled by the owners.