Building or retrofitting buildings and housing to make them "green" and energy efficient could have big and relatively fast environmental and economic benefits, according to a report by PennEnvironment.

The 20-page report released in Pittsburgh and nationally yesterday by the environmental advocacy group said adoption of federal and state policies and codes promoting use of high-efficiency windows, lighting, and heating and cooling systems would result in significant energy savings for home and building owners and reductions in emissions of greenhouse gases, which contribute to global warming.

"We need policies and commitments from all levels of government to protect the environment from global warming and prevent runaway energy costs," said Erika Staaf, PennEnvironment water advocate. "We are echoing Gov. Ed Rendell's call for a statewide 'green' building code."

Such a code would mandate energy-efficient construction techniques, use of recycled and sustainable materials, and mandate efficiencies in heating and cooling systems.

As a first step toward such a code, state Rep. Matt Smith, D-Mt. Lebanon, said he has introduced legislation that would require building projects receiving state funding to meet national environmental building standards -- known as Leadership in Energy and Environmental Design or LEED standards -- and achieve an 85 percent EnergyStar efficiency rating.

"I've talked to developers and we're to the point that the extra up-front costs of building green are either zero or negligible and would be paid back in three to five years of energy cost savings," Mr. Smith said. "So for the 30 years or more life of the building the payback to taxpayers is enormous."

He said HB 444, which has bipartisan support from more than 40 co-sponsors, has been cleared by the House Energy and Environmental Resources Committee and is under consideration by the House Finance Committee. It would apply to new school, prison and state office building construction as well as retrofits of older buildings.

Earlier this year the Pennsylvania Legislature approved a $25 million grant program to promote environmentally efficient new or retrofit construction for homeowners and small businesses.

About 40 percent of America's energy, 10 percent of all the energy used in the world, is used to power buildings and homes. The report said much is wasted through poor insulation, leaky windows and inefficient lighting, heating and cooling systems.

Holly Childs, executive director of the Green Building Alliance, said there are already 56 green-certified buildings in Allegheny County, 33 of those in the city, and more about 50 more buildings that are registered and awaiting certification.

The report recommends improving and enforcing building codes to require 30 percent greater efficiency by next year and 50 percent by 2016, adoption of the Obama administration's target of making new buildings "zero energy," meaning they have a net zero energy consumption, by 2030, and retrofitting of all existing commercial and residential buildings before 2030.

Meeting those goals, the report said, would save 144 quadrillion BTUs, or enough energy to power all the buildings, cars, homes and power plants for 11/2 years, and prevent emissions of 11.2 billion tons of carbon dioxide, almost equal to all the carbon dioxide emissions from the U.S. and China combined in a year.

Payback on those retrofits would occur in 11 years and would result in more than $542 billion in energy savings by 2031. It also would cut U.S. carbon emissions by 34 percent, a significant slice of the 80 percent reduction many scientists say is needed by 2050 to reduce global warming and its effects.