The International Window Film Association (IWFA) has reported that California residents could save the equivalent of four million barrels of oil each year, or the annual output of three 500-megawatt power stations, by installing window films on 10 percent of structures built before building energy codes were mandated.

The California Building Standards Commission recently approved a new code which goes into effect in 2014, adopting extensive energy code requirements voted by the California Energy Commission (CEC) in 2012.

“We need to continually look for smart, cost-effective ways to save energy and reduce peak electricity load,” says Commissioner Andrew McAllister of the CEC. “Window film is a product that needs to be considered as an important retrofit solution as we upgrade legacy dwellings in the Golden State.”

Independent analysis conducted by ConSol, a California-based energy consulting firm, shows window film is one of the most cost-effective measures to reduce energy use in California. In fact, window film outpaces traditional techniques such as updating HVAC systems, air sealing and caulking or adding R-38 ceiling insulation. ConSol’s study used many of the same processes the CEC utilizes in determining relative value of energy savings for the state. The complete report can be found here.

In California, there are nearly 9,000,000 dwellings built prior to the energy building codes. By professionally installing window film on just 900,000 dwellings, or 10 percent, ConSol conservatively estimates window film may cut a typical building’s annual energy use by 10 percent. Together this could add up to 7,150,250,000 kilowatt hours. The savings is comparable to what three power plants could produce annually, or the conversion equivalent of 4,000,000 barrels of oil, according to ConSol.

“Without a doubt, window film offers an enormous potential for energy savings in the California market and consumers may not need to replace their windows at all,” says Darrell Smith, executive director of the IWFA. “We hope that policy makers in other states will take California’s lead and develop programs that encourage this extremely cost-effective solution for consumers.”