According to the EPA, car air conditioners use seven billion gallons of gas every year. That  translates into 16 million tons of additional carbon.

 As part of its implementation of the aggressive California Global Warming Solutions Act, or AB 32, the California Air Resources Board is investigating what can be done to keep people from using their car's air conditioner. One solution under investigation is how to keep cars cool in the first place, including heat reflecting paint, solar fans and special glazing. Cooler cars are one of AB 32’s early action items, to be addressed by 2010.

Unprotected cars sitting in the sun for hours at a time can reach temperatures of 130 degrees and higher.  In fact, temps inside cars can rise by 40 degrees in less than an hour.  Under conditions like that, people understandably scramble to hit the AC button. 

In an effort to keep the solution as simple as possible and keep drivers away from their AC, California is looking at how to cool cars down before they emit, using a variety of technologies.

1. Solar cooling paint: An exterior coat of paint that reflects solar rays of different frequencies, reflecting nearly 80% of rays to reduce the heat of a car by up to 19 degrees. Reflective paint is essentially a form of insulation and has been available for exterior buildings and roofs for quite a while, saving buildings approximately 5% in energy costs.

2. Solar ventilation: Powered by a small solar array,  fans that turn on when triggered by intense sun or the heat of a vehicle, moving hot air out of the cabin. This approach is conducive to modifying sunroofs to slightly open when the car reaches a certain temperature.

3. Reflective Window Glazing: Similar to window tinting, reflective glazing coats the window and is specifically designed to minimize a vehicle's heat gain. 

Initial tests indicate that these cooling technologies, working in tandem, can reduce a car’s internal heat by 39 degrees and have the potential to trim the AC fuel use of an automobile by nearly 30%. If California prevails, such technologies will be mandated for new cars in the near future.

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