Forget the myth about black paint and hot cars
By TERRY BOX/DMN
Twenty years ago, when I was young and dumb, I bought a black Volkswagen GTI. Want to know the most toxic element in that combustible mix? The color. For a while, before the rattles and oil leaks started, the GTI was a great, soulful little driver. But my most vivid memory of the car was having to take off my shirt in August so I could use it to open the door after leaving the car in direct sunlight for hours.
For 20 years, I have urged people in this shadeless, concrete-slathered sector of Texas to avoid black cars because they are generally hotter than the surface of the sun.
As it turns out, I was only partly right – a surprising discovery I made recently during a little experiment conducted by Craig Eppling, the regional head of public relations for General Motors Corp.
Here's the bottom line: If we've met at a party sometime over the years and I told you to stay away from black, pretend I was drunk.
Mr. Eppling, who has been active this summer in programs that combat the very serious problem of people leaving their kids and pets in sealed cars, proved me wrong in one hot afternoon.
He parked a red Buick Lucerne, a white Chevrolet Impala and a black Saab SUV on a concrete parking lot in Carrollton one afternoon in mid-July. All were late-model, low-mileage vehicles.
There were thermometers in each car, and readings were taken every five minutes between 2 p.m. and 4:30 p.m.
The temperature outside ranged from a toasty 93 to a torrid 102.
The red Lucerne was left to bake with its windows up. The white Impala started the test with its windows down a quarter of the way, and they were lowered all the way at 3:40 p.m. The black Saab had darkly tinted windows that were left up.
At 4:20 p.m., when the temperature hit 102 degrees outside, the black Saab with gangster glass rolled up tight registered an interior temperature of 125.8. The white Impala with the windows down had an interior temperature of 127.2 degrees, and the red Lucerne with untinted windows up all the way was sizzling at 139.5 degrees.
All those temperatures are dangerous to kids, pets and older adults. The Lucerne could be lethal.
None of this surprised Jan Null, an adjunct professor of meteorology at San Francisco State University, who has done research on heat and sealed vehicles.
"The exterior of a black car gets hotter than a white car, but it does not get transferred to the interior any more than in a white car," he said. "Try this experiment: Take your hand and put it on the headliner. It's not very hot. The energy that heats up the inside of a car comes through the windows."
That can be serious business in August in desert locales like Baghdad or Dallas.
"In the first 10 minutes, the temperature inside a car with the windows rolled up will rise 19 degrees," Mr. Null said. "In the next 10, it goes up another 10 degrees. After an hour, it's usually up 43 degrees."
Some areas of a vehicle get even hotter.
On a 95-degree day, for example, asphalt street surfaces will hit a temperature of 150 degrees. The top surface of a black dashboard typically reaches 175 degrees.
"Some slow-cook recipes use that temperature," he said.
Now that I'm older and slightly wiser, please let me amend two decades of advice. Buy a government-issue white vehicle and get the windows tinted dark. It might not look great, but it will be cool in a real-world way.