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A Zero-energy Home
An exclusive excerpt from the Shelter chapter.
We don’t often think of our homes as gas-guzzlers, but buildings account for 50 percent of energy consumption in the United States and for more greenhouse-gas emissions than automobiles.
We can burn less energy without sacrificing comfort. We can heat and cool our homes with nothing but sun, shade, and breeze. In fact, it is possible to “zero out” our energy consumption so that we generate as much power as we use, and sometimes even achieve a surplus that can be fed back into the power grid and used by someone else.
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Architect Zoka Zola’s Zero Energy House on Adams Street in Chicago is a terrific example of a stylish, energy-balanced dwelling. The building is completely self-sufficient, generating 100 percent of its own power on-site through solar and wind energy.
The Zero Energy House emphasizes passive techniques for generating energy and maintaining indoor comfort. “Passive” solar energy makes use of existing conditions and natural methods like conduction and radiation to heat a building. (“Active” solar energy, by contrast, requires pumps and motors to circulate heat and power collected by solar panels and shingles.) In the case of the Zero Energy House, the building’s structure has been designed with passive solar in mind—the house’s orientation, overhanging rooflines, strategically placed shade trees, and carefully installed insulation allow it to capture sunlight and heat. Thermal mass, another passive technique, uses exposed surfaces to absorb heat in daytime and radiate heat at nighttime or during low temperatures. In the winter, the Zero Energy House’s south-facing windows allow ample sunlight into the house, heating the concrete walls inside. In the summer, shade trees act as passive means of cooling, blocking hot sun rays from the house.
During warmer months, natural ventilation keeps temperatures stable by allowing cross-room circulation between open windows and skylights. This approach can eliminate the costs, noise, and environmental problems associated with air-conditioning and fans. To make cooling even more effective, plants surround the building offering insulation, shade, and protection from UV exposure. Ivy shrouds the building’s exterior, and other foliage covers the building’s roof. The green roof absorbs rainwater and provides extra space for planting a diverse range of native and edible greenery. It can be used as leisure space and it protects the building from the damage normally cause by temperature fluctuations and sunlight.
It’s easier to implement these types of energy-efficient building strategies during the construction process than it is to add them to existing buildings. Because the Zero Energy House was designed and built from the ground up, the architect was able to study the natural cycles at the site in order to establish a symbiotic relationship between the house and its environment. For example, the architect mapped out the location of the sun (and corresponding shade) at various points during the year to ensure that the house would always be efficient, regardless of weather or season.
Though the Zero Energy House is a large-scale project, building to take advantage of renewable energy doesn’t have to cost more, at least in the long run. Building a new home with well-planned orientation, good circulation, and proper insulation makes for an inherently less energy-intensive dwelling. Once these passive design strategies are in place, you can watch the savings pile up—proof positive that eco-friendly construction is also wallet friendly.
— Sarah Rich & Jeremy Faludi
Top Five Things You Can Do to Conserve Energy1. Get a home-energy audit: Many utility companies offer free home-energy audits that evaluate your current cooling and heating systems and insulation, assess air quality and problems with dust or dampness, and hunt out the source of drafts. Auditors provide a range of solutions sensitive to your price bracket. You never know what they’ll turn up: something as simple as installing a programmable thermostat could greatly reduce your home’s carbon emissions. 2. Use dimmers, automatic times, and/or motion-detection sensors: All of these will help reduce the amount of energy your light fixtures use. Automatic times and motion detectors are perfect for rooms where lights are frequently left on and forgotten about, or for hallways and outside lights. 3. Lower air-conditioning costs: Clean your filters regularly; dirty filters can cause energy consumption to skyrocket by restricting airflow and thereby making air-conditioners work twice as hard. If you have central air-conditioning, resist the urge to crank down the thermostat lower than necessary—you won’t cool your home any faster by trying to speed up the process. Keeping the thermostat at a steady 70 degrees Fahrenheit (21 degrees Celsius) is actually a more efficient way of cooling your home. 4. Install proper insulation: If your home’s insulation works properly, the heat it traps does a great job of offsetting heating needs, which means less consumption and lower bulls. Check existing insulation for gaps and wear, which effectively eliminate any savings that insulation offers and allow condensation to accumulate and form mold, a significant health hazard. 5. Modernize your windows: Inefficient windows are horrendous energy wasters. Good, triple-glazed windows can save significant amounts on heating and cooling, often counterbalancing a less-than-optimal heating and cooling system. Like proper insulation, good windows also help control condensation and mold, and help keep a consistent air temperature throughout the house. Efficient windows now bear the government0standard Energy Star label, which can help consumers choose wisely.
—Carissa Bluestone
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