Study Shows White, Silver Car Paints Offer You the Best Fuel-Saving on the Road
Remember back in grade school (or high school) when your science teacher said that light colors repel light, while the darker ones absorb it? Well, guess what? They also apply to cars paints--and apparently how much you can save on gas and car emissions.
According to a study made by the Heat Island Group at the Berkeley Lab Environmental Energy Technologies Division (EETD), the degree of lightness or darkness of your vehicle's paint color can affect its use of the air conditioner, its fuel efficiency, and how much pollution it emits to the environment. And interestingly enough, their studies concluded that white (or silver) is the car paint color that uses the least energy, fuel, and vehicle pollutants on the road.
Here's the study and its results
The researchers made an experimental comparison of two identical Honda Civic cars--one black and one silver car paint. They were parked facing south, in Sacramento, California for an hour, and increased the solar reflectance (SR) (ρ) of both of the car's shell by about 0.57ρ. They garnered these results:
1. The silver Civic was cooler compared to the black Civic.
The silver Honda Civic had a cabin air temperature of around 5-6°C (9-11°F) compared to the black Honda Civic.
2. The silver Honda car required 13 percent less air conditioning (AC) capacity to cool its interior cabin air to 25 °C.
And according to their simulations, there were two significant results when air conditioner use is lessened:
- Lessening the use of air conditioner increased the silver Honda's fuel economy by 2 percent
- Lessening the use of air conditioner also decreased the silver Honda's emissions of CO2 (1.9 percent), NOx (0.8 percent), CO (0.79 percent) and Hg (0.67 percent). And according to their study, these reductions are expected to be greater when it comes to "actual, real-world" driving.
Light and heat explained
To make you understand why this is the case, allow us to explain the basics of light energy.
When light hits a surface, such as your car's hood, some of its heat (energy) is reflected, while some is absorbed.
White contains all colors and is the most reflective. This means that it bounces most of the heat from the sun away from the surface. Black, which has the absence of color, absorbs most of the heat--and at a much faster rate.
The closer to pure white your car paint is, the more light it reflects out. Pastel colors, or beige and off-white colors are also quite reflective. That's because they're tinted with the pure white color, which consequently increases their light reflectivity (tinting). The more light is "reflected" away from the paint, the lesser the heat is generated on the surface. The lesser the heat, then the lesser it takes to cool down air temperature in and around a vehicle.
Meanwhile, black-colored vehicles absorb more light. Similarly, you can decrease the reflectivity of your car's white, pastel or beige paint by adding more black color to it (shading). The more light is absorbed by the paint, the more heat is generated on the surface. And the hotter it gets, the longer it takes to cool down the vehicle's air temperature.
So, that's it. It seems your science teacher was right when she taught the physics of color and light, after all. Hopefully you were fully awake when she taught you that lesson. You never know--one day, you might use that to buy your own car.