The Associated Press reports that when the temperature on a roof is measured with an infrared gun, white roofs can be 45 degrees cooler than conventional dark-colored roofing material.

This difference means cooler indoors that need less air conditioning to cool, which makes a building more energy efficient.

This “cool roof” program has taken off in cities like New York City.

The program of making cool roofs entails nothing fancy. It’s extremely low tech and low cost, a potent combination that looks very attractive to those who are strapped for money in this economic climate. All it takes is white paint and some elbow grease!

Energy secretary Steven Chu says that the idea is catching on. And why won’t it? Why would people want to pay a higher electric bill when they can have a much lower one?

Chu announced in July that the Department of Energy buildings would be painted white wherever possible.

In Arizona, cool roofs are mandatory for state-funded buildings; Philadelphia has an ambitious green-energy plan with cool roofs as a focus.

In New York, the Department of Buildings and other public and private groups have committed to paint 1 million square feet of roofing on city-sponsored community buildings.

For those interested in giving their homes a cool roof, the Cool Roof Rating Council provides information on materials and resources at its websites.

For those who want to truly invest in infrastructure by replacing a conventional roof with one that’s made of material designed to reflect the sun’s heat without a painted coat, the Department of Energy says that there are no federal tax credits for roof coatings, but a tax credit is available for using cool materials when replacing a roof. There’s a range of materials that can reflect the sun’s heat to keep buildings cool.

But even if people want to simply stick with paint, Arthur Rosenfeld, a former California energy commissioner, says that an average 1,000 square-foot roof painted white can save 10 tons of carbon dioxide, the equivalent of emissions from one car for about two and a half years.

On a national scale, cool roofs could eliminate 2 billion tons of CO2, roughly the same a taking 20 million cars off the road for 20 years, according to Rosenfeld.

Let’s hope more homes and businesses take this simple step to make their buildings more energy efficient.

As always, should you choose to paint your roof white, exercise safety precautions when working on the roof. It won’t do much good if a lower electric bill turns into a hefty hospital bill because you fell off the roof!