Myth: Using the AC Drastically Lowers Gas Mileage
There’s a segment of the population that will suffer through a heatwave with the windows down rather than touch the AC button. They believe the air conditioner is a massive fuel hog. While it is true that the AC compressor puts a load on the engine and uses some extra gas, the “cost” is often exaggerated. In modern cars, the impact on your MPG is usually quite small.
In fact, at highway speeds, rolling your windows down creates so much aerodynamic drag that it can actually be less efficient than just running the AC. While you might save a tiny bit of fuel in slow city traffic by keeping the AC off, the trade-off in comfort usually isn’t worth the few cents you’ll save.
