Austin's Star System Keeps Score

Austin Energy's Green Building Program services include a ranking of new homes on a five-star scale for their resource efficiency.

The rating is a composite of basic building requirements, including nine that are not in the city's mandatory building codes, plus meeting certain international energy rating codes.

Green Building Measures feature an optional menu of extras to make the building even greener. Ratings summarize performance in six areas: energy efficiency, water efficiency, materials efficiency, health and safety, community, and testing protocol.

Energy efficiency rating-This part of the rating addresses the home's design, construction, and operation. The building is examined for its lot orientation, proper construction of the thermal envelope, high-efficiency heating, ventilation, and air conditioning systems, well-sealed ductwork, and controls. Points are awarded for compact fluorescent bulbs, Energy Star appliances, and for renewable energy both active and passive. Shading, cool roofs, and proper placement of windows round out the energy portion of the checklist.

Water efficiency rating-This measures mostly outdoor water use. Daily water use generally doubles in the summer lawn-watering season. Emphasis is placed on climate appropriate landscaping (like xeriscape), organic soil amendments, wise watering, and rainwater catchment systems. Indoor water saving measures like low-flow toilets and showerheads, and high-efficiency dishwashers and washing machines are recommended, but figure less prominently in the rating system.

Materials rating-This measures resource depletion, durability, and the environmental burden of solid waste. Reductions in the amounts of materials used are also sought. Points are awarded for products that are certified as being sustainably manufactured by third-party examiners like Green Seal and the Forest Stewardship Council. Use of local products like limestone, granite, cedar, pecan, and mesquite are favored, along with composite materials such as decking made out of a mixture of wood and plastic.

Health and safety rating-This measures the use of paints that don't give off out-gassing toxins, cabinets that are free of formaldehyde, exhaust ventilation fans, pleated media or electronic filters, as well as dehumidifiers.

Community rating-This covers site-level and neighborhood issues. Good site planning saves trees and native vegetation. Sites located closer to existing amenities like shopping, parks, and workplaces reduce driving trips.

Testing rating-This measures the quality of workmanship. Among the tests used are those for house air leaks, supply air flow, duct leakage, and combustion gas backdrafts. All four tests are required for four and five star homes.

Mary McLeod, residential program coordinator for the Green Building Program, says "The ratings are an educational tool for both the building professional and homebuyers."

The program goals are to "reduce energy use, reduce peak demand and reduce air emissions." Through September 2004, the program has rated about two thousand multifamily apartment units, three-point-three million square feet of commercial space, and nearly thirty-five hundred single-family homes. Claimed benefits to the homebuyer include greater comfort, a healthier home, and lower maintenance.

-Stephen Beers