Some estimate that the new requirements, including tests for duct leaks in crawl spaces or other areas not within a home's air-conditioning envelope, would add $800 to the cost of a new home, Cox said. But they also could save $200 to $300 a year on energy costs, meaning they would pay for themselves in a few years.
Cox also worries about safety issues, which would be fixed under the 2009 code. A leak in the crawl space could create a downdraft that becomes a carbon monoxide hazard, he warned.
The bill also calls for improvements in lighting efficiency.
Some home builders have knocked the proposal as costly.
The Utah Association of Realtors has some concerns, but no official position, spokeswoman Deanna Devey said. "There was a bit of concern that it could raise the price of a home and hinder our efforts to provide affordable housing."
The bill already has failed one vote in the House Rules Committee to assign it to another committee for debate.
The same measure went nowhere last year, and Rep. Mike Morley, R-Spanish Fork, remains among the skeptics.
"It still has a very low return on investment," said Morley, a real estate developer. "The housing industry is still weak, and I think the same concerns which existed last year are still of concern today."
Utah Clean Energy backs the measure and believes it's a cost issue for every electrical ratepayer whose bill rises with construction of new power plants.
"It's affecting everyone who buys a new home," UCE policy associate Kevin Emerson said, "but it's affecting everyone else who pays a power bill.
Read the bill
O Read the proposal on building code upgrade > 1.usa.gov/zqGQwS