Auto Service World
News   August 12, 2004   by Auto Service World

Wind ’em Up and Crank Up the A/C to Save Fuel

Contrary to some recent reports, you’re not necessarily saving fuel by keeping your air conditioning off and your windows open.
As the summer temperatures remain hot and gas prices remain high, motorists should remember that vehicles can get better fuel efficiency with their windows closed and air conditioning on when at highway speeds. During stop-and-go traffic, however, it’s more fuel efficient to open the windows, according to the Automotive Aftermarket Suppliers Association (AASA).
With the windows closed on the highway, the vehicle’s aerodynamics are improved as there is less drag on the vehicle, according to Frank Hampshire, AASA director of market research. He noted that studies by Volvo and other automakers have shown that a cooler, drier and quieter cabin can reduce fatigue on longer trips and help a driver stay alert and relaxed for a longer period of time.
"In city driving, you will see a slight fuel economy advantage by opening your windows, but the use of air conditioning at higher speeds can produce a fuel savings," Hampshire said. "There are other ways to improve your fuel efficiency with the top advice clearly being to have your vehicle serviced regularly and driving wisely."
Some consumers with malfunctioning car air conditioners may opt to roll the windows down rather than make repairs, but that’s a false economy, Hampshire noted. "The fuel efficiency savings may not be enough to pay for the repair of a non-functioning air conditioner. However, for motorists with malfunctioning systems who have decided to endure the heat, fuel savings make air conditioner system repair worth considering," he said. "Furthermore, a functioning air conditioner system might be necessary for proper functioning of the windshield defroster in late model vehicles."
According to the U.S. Environmental Protection Agency (EPA), there are several other tips a motorist can follow to improve gas mileage, including:
— Go easy on the brakes and gas pedal. Avoid "jackrabbit" starts by accelerating gradually whenever possible. Also, anticipate stops to avoid sudden braking.
— Avoid long idles. Turn off the engine if you anticipate a lengthy wait. Instead of idling at a drive-up window, park the car and go in. Idling burns more gas than restarting the engine.
— Avoid carrying unneeded items in the trunk. Extra weight decreases gas mileage. Also, reduce drag by placing items inside the car or trunk rather than on roof racks.
— Keep tires properly inflated and aligned. Periodic wheel alignments and keeping tires inflated to the maximum recommended pressure can improve your gas mileage.
— Get regular engine tune-ups and car maintenance checks. Tune-ups improve performance as well as gas mileage. Incorrect fuel ratio, bad spark plugs and incorrect spark timing can have a huge effect on gas mileage.
— Avoid stop and go traffic by taking alternative routes or less congested travel times.
— Use a good engine oil, preferably a synthetic or standard oil treated with a friction reducing oil additive. These have been known to improve fuel economy by as much as 12 percent.
— Use your cruise control whenever possible.

The Motor & Equipment Manufacturers Association (MEMA) established AASA in 2002 as its aftermarket segment association to exclusively serve manufacturers of aftermarket components, tools and equipment and related products. For more information, go to

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