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Transitioning to Net-Zero Living

Judith and Jeffrey adore living in Belfast, Maine – a quaint harbor town of Belfast, Maine. They previously resided in a large seaside home on Penobscot Bay, where Little River formed an estuary. Unfortunately, significant time and resources were required to maintain and heat the older home with wood and oil. Although Judith and Judith cherished spending time by the bay with friends and family, they decided to list the home for sale and move into a net-zero energy home at Belfast Cohousing & Ecovillage.

“Everyone knows Americans consume resources at a rate that is not sustainable,” Jeffrey says. “I always thought I was making my contribution by recycling and driving an economical vehicle. At the same time I was living in an enormous house that, in a third world country, could house 10 families. Before we insulated the attic we were using close to a thousand gallons of oil each year. This is not a sustainable number for two families, as we had a rental apartment in the home.”

 Their New Net-Zero Home

Their new 1,500-square foot, high-performance home is primarily heated by passive solar gains through their large south-facing windows. A relatively modest 4.5 kilowatt solar system produces all the energy the home uses over the course of the year. Because the home is all electric, solar energy heats the water and home, and powers appliances, with no supplemental fossil fuel or wood use.

 Net-Zero Home Design

When planning a net-zero home, it’s recommended to start with energy efficiency and then size the solar system. Judith and Jeffrey’s home has an insulated foundation; 10-inch thick walls; numerous large south-facing triple-pane windows; triple-pane doors, and is oriented for optimum solar gain. The slab-on-grade foundation slowly warms up on sunny winter days, and gradually releases the heat when temperatures drop. The house is air-sealed, making it virtually airtight and keeping heated air inside. Even on the coldest windy winter days, Judith and Jeffrey sit in front of the windows and feel no drafts.

To ensure optimum quality air and comfort, the home has a Zehnder heat recovery ventilator. It supplies a continuous stream of fresh, filtered air to the three bedrooms and office, while exhausting stale air from the kitchen and two bathrooms. Coolness in the summer and heat in the winter is recycled from the exhaust air to the incoming air, enabling both a high level of energy efficiency and comfort. Unlike many code-built homes where air enters through leaks in the walls, comes up from the basement or crawl space, or in from the attached garage—the outside air intake on Jeffrey and Judith’s home is strategically  located to avoid bringing pollutants into the home.

In most homes, a 4.5 kW solar system would not be sufficient to generate all the energy the home consumes, including space heating, water heating, and cooking.  Judith and Jeffrey’s home has a winning combination of efficiency and renewable energy, making a net-zero home possible.

Their home is located in Belfast Cohousing & Ecovillage, a 36-unit community of high-performance homes that are clustered to preserve open space for agriculture, wildlife and recreation. Although Judith and Jeffrey’s new home doesn’t have views of the harbor, it does overlook Little River Community Farm. Members of this worker-share farm gather each week to harvest produce and maintain the land.

“My wife and I are making our ‘seventh generation’ contribution now,” Jeffrey explains. “We want our grandchildren and future generations to live in a world that is as green and beautiful as this one is now.”