About 90 percent of the windows in today's homes are older, single-pane glass styles - much less efficient than modern double-pane, triple-pane and argon-filled products, noted Maureen McDonough of Andersen Windows. A new federal energy-efficiency tax credit and supplying windows for Project ReEnergize contractors were important factors in enabling the manufacturer to call back 600 employees who had been laid off, she added.

Participating home owners had no income limits, but the homes could be no larger than 3,000 square feet and had to be built before the year 2000, when more stringent state energy codes were mandated. The average size of each home was 1,800 square feet and the average age was about 45 years old, Weaver said.

The home builders association stands ready to funnel more money to consumers to make upgrades should additional federal funding become available. "We have a list of people who are waiting," because most consumers are unwilling to make the upgrades without the financial incentives, Nelson said.