ALBANY, N.Y. — Wear a black T-shirt on a hot summer day, and you’ll feel the basic principles of physics at work: Dark colors absorb more heat than lighter ones.

But can this simple lesson in heat absorption be applied to cool your electric bills?

President Obama’s energy secretary, Steven Chu, says yes and is urging Americans to install white roofs to slash cooling costs and help reduce global warming.

White material bounces sunlight and heat off a building’s roof and doesn’t absorb as much heat as a black roof, allowing the building to stay cool. In conjunction with special roofing materials that diffuse heat absorbed by the roof due to infrared light, a cool roof will keep a building cool without additional air conditioning, saving homeowners money on electric bills.

Chu is a longtime advocate of geoengineering, which involves the manipulation of the earth’s current climate to manage global warming.

“If you look at all the buildings and if you make the roofs white and if you make the pavement more of a concrete type of color rather than a [dark] color and if you do that uniformly, that would be the equivalent of … reducing the carbon emissions due to all the cars in the world by 11 years — just taking them off the road for 11 years,” Chu said.

California has been a pioneer in geoengineering, requiring all flat roofs be white and that any sloped roof be of light color since October 2005. This, combined with other energy saving measures, has already saved $56 billion in electricity and natural gas since 1978.

But dubious northeasterners may rightly raise an eyebrow or two at the idea, since we experience more cold days than hot ones.

True as this may be, residents of upstate New York still stand to save with a white roof. During the cold days of winter, black roofs don’t absorb or retain much heat. With fewer sunny days, shorter hours of sunlight and the sun’s low angle in the sky, any potential heat gain from the sun is virtually lost, say researchers at the Lawrence Berkeley National Laboratory. Then there’s Mother Nature, installing her own white roof every time it snows.

“You’re going to save money and make a wise decision,” said John Versace, owner of Ultimate Roofing, based in Hudson, N.Y. Versace has installed more than 1,000 white roofs, on commercial and residential buildings.

The cost of installing a new white roof is about the same as installing a traditional roof, but the benefits come over the long term. White roofs reflect significantly more infrared radiation than black roofs, allowing the asphalt product inside the roofing to not dry out, extending its lifetime. Retrofitting an existing roof is also an option, costing less than half of what it would to install a new roof. A fluid coating is applied to regular asphalt material and has the same properties as a new cool roof.

The real savings you’ll be able to see monthly will come in the form of your electricity bill. With a white roof, the inside of your home will be kept much cooler, reducing the need for air conditioning.

Versace describes the savings as “significant” and boasts that customers have seen up to a 15 percent to 20 percent cut in their cooling bills.

The only real maintenance needed to keep a white roof efficient is a top coat every 15 to 20 years to keep the white at its brightest.

Real estate agent Stephen Staples of RealtyUSA admitted that while installing a cool roof won’t immediately add to the marketability of a home, since it’s a relatively new concept, the roof will last longer, and should be something homeowners take into consideration.

The secondary benefits of having a cool roof are that using less air conditioning creates less carbon dioxide from power plants, which directly reduces global warming.

To see if your home could benefit from a white roof, the Environmental Protection Agency and EnergyStar offer a cool roof calculator that shows the potential savings of a cool roof. The calculator, available online at http://www.roofcalc.com, takes into consideration building type, heating and cooling systems, current roof information and weather details to offer an annual savings estimate.What makes it cool?

Cool roofs have two components to them: solar reflectance and thermal emittance.

Solar reflectance refers to how much light is reflected off the roof, or its albedo. Darker roofs have a lower albedo, so more sunlight is absorbed.

Thermal emittance is the ability of the roofing material to re-emit heat it has absorbed as infrared light. Higher rates of emittance allow heat to move away from the roof quickly, not allowing the energy to heat the building below.

Think of it this way: Solar reflectance is the white shirt you wear to stay cool and thermal emittance is your ability to sweat, or remove heat from your body.

Standard black roofing has a high emittance value, but a low reflective value, so simply changing the color of your roof can help keep a house cool. For more energy savings, choose a roofing material with a higher emittance value.