Green Begins at Home
You can pursue the ultimate in efficiency with a net-zero-energy house.
By Eric Schneider
In these days of climate change and widespread economic hardship, few ideas hold more promise to help with both issues than increases in energy efficiency. Many people have already taken measures such as, for example, replacing incandescent light bulbs with compact fluorescent lights (CFLs).
Some Americans are taking this idea to a more comprehensive level by striving to create net-zero energy homes. “The basic idea is that your home produces at least as much energy in a year as it uses,” explains Ann Edminster, an environmental design consultant in Pacifica, California, and author of Energy Free: Homes for a Small Planet (Green Building Press). Creating such a home means trying to balance energy usage with energy production. “That means, inevitably, that a net-zero energy home has a renewable energy system of some sort,” Edminster says.
Home energy often entails use of photovoltaic solar panels that convert sunlight into electricity. “The dominant solution right now is photovoltaics for electricity,” says Edminster, “with solar hot water coming in second place and wind energy third.” But she notes that solar panels require significant roof area and a wind turbine requires quite a bit of land.
One homeowner who uses the sun’s energy is nonprofit director Bill Mott of Providence, Rhode Island, who has a 5.2-kilowatt system. “We took advantage of a great Rhode Island state fund for alternative energy and ever since have been net exporters of electricity to the grid,” he says.
Few homeowners have reached net-zero energy status. One exception are architects David Pill and Hillary Maharam. Their rural Vermont home, the first in the state to receive a platinum LEED (Leadership in Energy and Environmental Design) rating by the US Green Building Council (www. usgbc.org), uses a 10-kilowatt wind turbine instead of solar cells to help achieve net-zero energy. “A wind turbine was much more economically feasible,” Pill explains, citing the area’s substantial average wind speed. An all-electric house, it uses no fossil fuels. “The turbine fulfills all of our electric load and more. The house uses the sun passively in its design,” he says.
Key elements that allow Pill’s home to effectively absorb the sun’s warmth are its south-facing position and highly efficient windows. Without these and other efficiency steps, net-zero energy wouldn’t be possible. “The house needs to use an extremely low amount of energy first,” Pill says. “Even without our wind turbine, our house uses 83% less energy than an average home in the Northeast.”
Edminster endorses taking efficiency measures even if the goal isn’t net-zero energy. Homeowners need to minimize collective energy load—heating, cooling, lighting, etc.—through design and construction. “For existing homes,” Edminster says, “that can be as basic as sealing up air leaks.”
This can involve simple solutions such as window replacements and better insulation. “You can buy a lot more efficiency for your dollar than you can buy solar electric,” says Edminster. “But the irony there is that putting photovoltaics on your roof is so much less disruptive to a family’s lifestyle than comprehensive energy remodeling.” Solar panels are no substitute for shorter showers and shutting off lights.
Net-zero energy requires changes in both technology and behavior. “It’s all about lifestyle,” Edminster says. “Our carbon footprint isn’t just our house. People need to realize that their whole lifestyle has a carbon footprint, and the house is just a part of that.”