Energy-efficient homes saving Texans money
Building Toward Zero
Owning a house without racking up utility bills may sound like a dream, but some new homes in Texas can make that dream come true.
The average U.S. family spends $1,400 a year on household electricity, with about half of that spent on heating and cooling, according to the U.S. Department of Energy (DOE). The DOE estimates that traditional homes account for 35 percent of the electricity and 20 percent of the overall energy used in the United States each year. The agency estimates new zero-energy homes can reduce the amount of energy used by a household by up to 90 percent and virtually eliminate costly utility bills.
Zero-energy homes are springing up in Texas with Austin and Frisco, a city just north of Dallas, leading the way. Builders of zero-energy homes use solar and wind patterns, as well as high-tech insulation, to build houses that double as power plants and allow the homeowner to sell extra energy generated at certain times of year by the house to the home's utility company, offsetting purchases of energy from the utility at other times.
Zero-energy technology has been around since the 1970s, but it wasn't until the late 1990s that builders started seeing the technology's cost efficiency, said Richard Morgan, the program director for Austin Energy's Green Building Program.
In January 2004, the city of Austin teamed with Austin Energy's Green Building Program and the Austin Housing Finance Corporation (AHFC) to create the first zero-energy subdivision in the state. Austin Energy is the city's electric utility.
The city hopes to break ground by April 2006 in Montopolis, a community located east of Austin, said Julie Beggs, an AHFC spokesperson. The family-friendly community was chosen for its already subdivided neighborhood, vast amounts of land and proximity to Austin, said Beggs.
Zero-energy homes look like any other home, except for a few key differences. The houses maximize passive and active solar benefits, Morgan said. Passive solar benefits include taking advantage of natural conditions to help cool a home.
"That means not having large expanses of unshaded walls or windows facing east or west," Morgan said.
The houses also generally come equipped with metal roofs to help reflect the sun and cool the house off quickly.
"Metal roofs are more energy efficient, reflect a lot of heat and don't retain heat," Morgan said. "Regular roofs still emit heat into the house until 10 o'clock at night."
Metal roofs last about 40 to 50 years and can contain photovoltaic (PV) systems that convert sunlight into energy, Morgan said.
The homes also have spray-in-place foam for insulation. The lightweight foam creates a thermal envelope that eliminates outside air infiltration, a major cause of heat and air conditioning loss.
Dreams in all sizes
Peter Pfeiffer, an architect with Barley & Pfeiffer Architects, helped design and build a Frisco home that won the "Overall Favorite House" award in the Home Builders Association of Greater Dallas 2004 Parade of Homes tour. The two-story, 3,800-square-foot home requires an 8.5 kilowatt PV system.
The Frisco home requires more energy than the 900- to 1,300-square-foot homes the city hopes to put up in Austin, which requires a 4-kilowatt PV system. Both houses use the same types of layouts inside, Morgan said.
"You have to optimize the size of the home and not create spaces that aren't going to be used very much, [including] reducing hallways and making rooms the proper size and not having a lot of empty square footage," Morgan said.
The Montopolis homes also will include an air duct system that reduces the amounts of air lost and energy used to heat and cool the house.
"You don't want a lot of turns in that system because every time it takes any kind of turn, it creates resistance to the airflow," Morgan said. "We made them as simple as possible to lose less than 5 percent of the airflow through them. The average air leakage in Austin is about 27 percent. Five percent is a real efficient duct system."
The city plans to connect the houses to utility companies to make sure they don't run out of power and to enable the houses to contribute back to the companies' overall energy supply.
"During the day time, our anticipation is that for a big part of the day, except for the hottest part of the day, [the house will] be producing more energy than they'll be using, and it'll flow back into the grid and then turn backwards later and give them credit for the energy used at night or sometime during the day," Morgan said.
If the house's daily energy production and use don't average out to a net-zero consumption, then seasonal changes can balance things out.
"In the spring and the fall, [the system] will produce more energy than the house itself needs, and that makes up for the fact that in the summer and the winter, it doesn't produce enough energy for the house," Pfeiffer said.
The $950,000 Frisco house features other money-saving strategies in addition to its energy-saving capabilities, such as a water conservation system that uses 30 percent less water for indoor needs and supplies nearly all of its own outdoor water.
Since Montopolis has a poverty rate nearly three times that of Austin, the Montopolis project will comply with the Austin Housing Finance Corporation's S.M.A.R.T. Housing Initiative. S.M.A.R.T. stands for Safe, Mixed Income, Accessible, Reasonably Priced and Transit Oriented.
Adopted by the Austin City Council in 2000, the initiative encourages production of houses that are environmentally friendly, safe and available to mixed incomes.
The city planned to break ground in April 2005, but had to delay production plans due to rising infrastructure costs.
"In order to meet the net-zero standard for these homes, it would cost $8,000 to $10,000 more per unit," Beggs said.
The city has temporarily put the project on hold to reexamine the planned neighborhood.
"That does not mean we will not build on that track [in Montopolis] or scrapped the idea of net-zero altogether," Beggs said. "We just need to go back to the drawing board to see how we can meet the net-zero energy and affordability goals."
If the city is unable to meet the S.M.A.R.T. affordability guidelines while creating a net-zero energy consumption, the homes will still be more energy efficient than the everyday home. The homes will still have metal roofs to help reflect heat, utilize layouts to minimize large spaces and include energy-efficient appliances.
The city of Austin's Neighborhood Housing and Community Development will heavily market the homes to area residents first, Beggs said.
Due to fair housing regulations, the city cannot exclude any potential buyers, but the city would like to avoid displacing current homeowners who have lived in the area for 30 to 40 years, Beggs said.
The city will help these homeowners by providing financial assistance with down payments and mortgage credit certificates.
Way of the future
The city plans to finish all 86 Montopolis homes by 2009 and hopes interest in the program will spread.
"For residential and commercial [construction], Austin Energy is seeing more and more interest and application of on-site [energy] generation and we know that in the future there's going to be more and more and more of it, so we need to position ourselves now," Morgan said.