If you’ve ever had to park in the sun on a scorching summer afternoon, you’ve probably also dreaded getting back inside the hellishly hot vehicle.
Research shows that a car’s interior temperature rises about 19º Fahrenheit in just 10 minutes. After an hour or 2, the interior can be 40º to 50º hotter(!) than the outside temperature. So if you’re parked in 100-degree heat, your car’s interior could reach 150º in just an hour, and the dashboard and seats could be as hot as an oven on low (about 200º, enough to bake cookies).
Why do car interiors get so hot?
Sunlight enters your car through its windows in the form of short-wave energy and is absorbed by the interior. The interior then radiates this energy back in the form of long-wave infrared radiation. And while sunlight can easily pass through glass, infrared light cannot escape through the windows. The trapped energy (heat) then causes your car’s interior temperature to rise. Thus, a parked car offers a great example of the greenhouse effect at work.
The science behind this proves the common-sense theory that shade — any kind of shade — is your best bet for keeping your car cool in the summer.
- Park in the shade. Obvious, yes, but it works. By limiting the amount of direct sunlight your car gets, you’ll minimize the heat buildup inside. Plus, you’ll save your car’s interior from sun and heat damage.
- Get shades for your car. Car shades will work in a pinch to keep your car cooler when you can’t find an inch of shade. According to a study by the Florida Energy Center, conventional car shades can reduce the interior temperature of a vehicle by 15º and the dashboard temp by 40º. And radiant barrier system car shades — the foil-faced, reflective kind — can cool your car even more because they actually reflect the sun’s heat instead of absorbing it.
- Tint your windows. Because window tints either absorb or reflect UV light, they help keep your car cool (and your interior from fading). Just keep in mind that the laws regarding window tinting vary by state. Check with your local DMV before tinting your windows to make sure you’re complying with local safety laws.
Aside from these basic tricks, there aren’t any surefire high-tech ways to keep your car’s interior from baking. Aftermarket solar-powered fans and vents are available, but their effectiveness is hotly debated.
And, contrary to popular belief, research shows that “cracking” the windows does little to cool your car’s interior. Your car’s interior and exterior colors do the most to determine its interior temp.
Do you have any tips for keeping your car cool in the summer? Share them here.