Green Homes Special Series: Part Fourteen: Zero-Energy Homes

Many consumers are not yet making the connection between energy enhancements now and future savings, even with the area’s hefty jump in electric rates last summer, he says. There will be long-term effects to their bank account as well as to greenhouse gases. “Even with PV panels and solar hot water, people still wanted to pay the same as a market house,” he says. Bob Ward Companies offers consumers the option of an ultra-efficient home with its MEG, or Maximum Efficiency Greenland, series that can include solar electric and solar water heating systems. Denver affordable housing project The NREL teamed up with Habitat for Humanity of Metro Denver to develop a ZEH for the affordable housing sector in cold climate. The approximately 1,200-square-foot, three-bedroom home with a crawlspace used envelope efficiency, efficient equipment, appliances and lighting, and passive and active solar features to reach the zero energy goal. It took advantage of off-the-shelf technologies, volunteer labor and computer simulation for the design. The $125,000 for the Habitat ZEH included the cost of solar thermal and PV but not land and landscaping. A mother and her two young boys moved into the home in October 2005. NREL’s Norton says that his two full years of monitoring the home has found it to be a net producer of energy, producing 24 percent more energy than it consumed in one year, with just a bit less energy produced the second year. “The science is there. But getting a marketable ZEH is a challenge. Can you get the costs low enough to make it a marketable product? Access to funding on city, county, state and federal levels can make the difference,” says Norton. The household’s utility bill has averaged $17.14 of which $16.75 was the fixed charge. “Zero energy does not necessarily mean zero energy bills,” says Norton. “There are set fees from utilities and arrangements for compensation by each utility is different. If this home were located in Oak Ridge, Tenn., for example, the household would be getting a check from the utility.” New Jersey remodel Asdal Companies of Chester, N.J., was the first builder in the nation to create a zero-energy remodel. An abandoned Civil War-era cottage on a rural property was the subject of its cooperative effort with the NAHB Research Center and the NREL. Building America funded the design, development and testing of energy-saving systems. The strategy was to minimize energy consumption while obtaining on-site power from natural sources. The cottage is home for two adults and their teenage son. The modeled loads and the actual loads vary but the dollar net is still positive with the net metering and a renewable energy “credit” from the power company. “From the sale of these credits, we actually make money operating the building to the tune of about $2,800 annually on energy,” says company CEO Bill Asdal. Asdal says the greatest difference between typical remodeling and aiming for zero energy was that “the level of care and detailing are geometrically higher.” He had to train all the trades in the strategy, and quality control checks were made almost daily. “This level of oversight and care adds to overhead and raises the cost of the product. Testing in and out are fundamental to achieving a higher building performance.” What surprised him in the effort was how air leakage was far more important than insulation values. “We have been focused on insulation for decades while missing the ball on air sealing needs,,” he says. What was not a surprise was customer behavior. “They need training and a mindset to minimize consumption.” Asdal said his first energy-efficiency demonstration model was in Las Vegas in 2000. “For about $2,000 of incremental investment, we achieved a 44 percent reduction in energy costs. It was a 16.7 percent return on investment. There is nowhere for a consumer to get this return in any financial market. It does make sense to invest in energy savings and begin to think life-cycle costing rather than the consumer’s fixation with first cost.” Wisconsin residence Construction is expected to be completed by the end of 2008 on what is believed to be the first practical production in the Upper Great Lakes region of a net-zero residential home that can be reasonably and affordably replicated in a cold-climate region.

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