When it gets warm outside, your air conditioner becomes your best friend. This is most definitely true in your car, where temperatures can sky rocket to 170 degrees under direct sunlight. But most people these days are under the impression that the more you run your air conditioner the more gas your car will guzzle. Now that gas prices are higher than the cost to eat at McDonald's, people are starting to take precautions and do what they can to help with their cars fuel economy. The assumption that running your air conditioner burns way more gas is somewhat untrue. Leaving your air conditioner off makes barely any difference in the amount of gas you burn. With the advent of modern, more fuel efficient cars, this myth is busted!
The air conditioner draws its power from the engine which uses some gas, but with today's cars, this use of gas is minute. The AC in your car can decrease the fuel economy of your car up to 20% in some vehicles, but it depends on the type. Driving with the air conditioner is more fuel efficient than driving with the windows down. Driving with the windows down creates drag which means that your engine has to work harder to keep your car at the current speed; this burns more gas than if you just ran your AC.
In the long run, using your AC is far better than any other means of cooling yourself off in the car, unless you're driving in traffic. When you drive in traffic you aren't going very fast so the drag on the car is minimal. In these cases, you burn more fuel running the air conditioner than having the windows down. That makes sense. When you drive on the highway you can use either the AC or the "window down" method to cool yourself, because, honestly, there is no noticeable difference in gas usage at those speeds.
Here are some tips about you and the heat in your car. Before you get into a hot car, roll down the windows and let it air out. There is nothing worse than getting into a hot car, sitting on a lava hot seat, touching a super hot steering wheel, and breathing stuffy super heated air. Your car needs some time to cool down for itself and for you. Once you believe it is cool enough to actually sit on the seat, turn on the car and run the air conditioner on recirculation. This will help the car cool down much quicker, and you can be on the road fast without sacrificing a layer of your precious skin.
So now that you know the air conditioner can be your fuel efficient friend, maybe you won't be so quick to turn it off or ignore it in favor off putting the windows down and choking on bugs. The AC in your car burns much less gas than your window method, so give your air conditioner a chance and be cool in the heat.