Net-Zero Living in a High-Performance Home

| 1/9/2015 3:44:00 PM

Greater energy independence, freedom from fluctuating energy prices, and environmentally friendly living are alluring concepts that motivated my family to examine our housing and our lifestyle. We recently purchased a high-performance home and installed a solar system, making our home net-zero. We now produce as much power as we use over the course of a year.

Net Zero Living
Photo by Steve Chiasson

Realizing the Dream of a Net-Zero Home

To realize the dream of a net-zero home, we bought a superefficient home at Belfast Cohousing & Ecovillage, a 36-unit multigenerational community in Midcoast Maine with triple-pane windows and doors, virtually airtight construction, a solar orientation and lots of insulation. The sun, appliances and occupants provide a majority of the heat needed to keep our home cozy.

On sunny winter days, our heaters remain off, as the sun gradually warms the house. Electric baseboard heaters kick on as needed, primarily at night or on cold, cloudy days. The home is all electric—with an electric range, hot water heaters and space heaters. Because we don’t use propane, natural gas or heating oil, a solar system can produce all the energy that our home consumes.

Our home has a Zehnder heat recovery ventilation system to ensure high indoor air quality and comfort. Because the home is airtight, mechanical ventilation is essential for fumes and moisture from showers and daily activities to exit the building. Just as important, an airtight home needs a ventilation strategy for the incoming air. By incorporating a heat recovery ventilator, the constant stream of fresh incoming air is filtered and then preheated—pulling the heat from the outgoing air.

Our home doesn’t have exhaust fans. While they effectively vent stale air out of a home, they’re not energy efficient because the heat is not recovered when the air exits the home. Our heat recovery ventilation system recovers most of the heat, keeping our energy use down. Zehnder systems are up to 95 percent efficient, allowing our home to achieve a level of energy efficiency and indoor air quality that wouldn't be possible otherwise.