A/C or Windows Down: Which Gives Better MPG in the Summer?

During the summer months, one hotly debated topic is whether it’s more efficient to keep the windows down or use the air conditioning. While the A/C typically makes the engine work harder, having your windows down can decrease aerodynamic efficiency. So which is better between the two? The answer, quite simply, is that it depends.

A/C or windows down - Gossett Kia - Memphis, TN

According to Business Insider, there is no easy answer to the A/C vs. windows down debate. While experts can agree that neither is great for gas mileage, there are several factors to keep in mind when determining which of the two is best. This includes the make and model of your car, weather, and the speed you’re travelling. For instance, having the windows down has little effect on fuel economy if you’re going 15 mph. At highway speeds, however, it’s a different story.

Researchers for the Society of Automotive Engineers (SAE) have performed multiple studies to find the answer. A 2004 study looked at sedans and SUVs at speeds of 31 mph, 50 mph, and 68 mph in 86-degree weather. While it was close, having the windows down was consistently better at all speeds than running the air conditional.

For an SUV, the results are starker. Having the windows down rather than using the air conditioning will save you a considerable amount on fuel costs. The team at the Mythbusters television series also tested this problem and found similar results.

Ultimately, if the Memphis weather gets hot enough, the correct answer to the debate between A/C or windows down is likely to be whatever keeps you feeling coolest. If you want to look cool, you’ll want to get behind the wheel of a new Kia, and you can start your journey in that direction by stopping into Gossett Kia for a test drive.