Cool Cars

Increasing the solar reflectance of a car’s shell keeps it cooler when parked in the sun. This permits the use of a smaller air conditioner that draws less power and improves the vehicle’s fuel economy. Our Cool Cars project, sponsored by the California Energy Commission, measured temperature reductions and simulated energy savings attainable by using a light-colored or “cool-colored” car shell.
We conducted a cool cars experiment for the CEC in which we studied the difference in heat flux through a car's roof. We found that the interior of a light-shelled car stayed cooler than that of the dark-shelled car. (Image courtesy of Heat Island Group, Lawrence Berkeley National Laboratory)
Car shells have varying solar reflectance and thermal emittance values depending on the color and material. (Image courtesy of Heat Island Group, Lawrence Berkeley National Laboratory)

Over 95% of the cars and small trucks sold in California have air conditioners. The use of air conditioning (A/C) in cars increases fossil fuel consumption and tailpipe emissions. This project aims to reduce A/C usage by lowering cabin air temperatures.

The Cool Cars Project, sponsored by the California Energy Commission (CEC), investigates the benefits of using solar reflective cars. By reflecting more sunlight than dark cars, a cool car shell reduces the amount of heat that is transferred into the car's interior. This results in decreased cabin air temperatures along with associated reductions in air conditioning, fuel consumption, and emissions of greenhouse gases and urban air pollutants.

Contact

Ronnen Levinson
Principal Investigator
(510) 486-7494

George Ban-Weiss
(510) 486-4931

Resources: 
Car Shell Reflectance Database
Related Files: 
PDF icon Cool Cars Final Project Report