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Use your car’s air conditioner conservatively

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Using your car's air conditioner conservatively can lead to a trifecta of eco-friendly, money-saving upshots: improved gas mileage, less harmful emissions being released into the atmosphere, and a reduced dependence on foreign fossil fuels.

How to use your car's air conditioner conservatively

It's not rocket science, folks. Although it's easier said than done—especially for those living in areas where temperatures can reach sauna-esque highs during the summer—running your car's AC on low or turning if off and opening the windows instead is a significant way to save precious shekels at the pump and contribute less to greenhouse gas emissions. So roll 'em down, let the wind in your hair, and burst that climate-controlled bubble you call your car.

But remember, safety first. Don't let things get out of hand while trying to save money and the environment. If your dog or a carpool partner happen to be passengers, keep them cool. And if it reaches the point where your Buick might as well be a sauna on wheels, crank the AC back up until you feel comfortable. But let's get practical, shall we?

  • A good AC rule of thumb: In town, turn it down (or off); going fast, let is blast. Experts recommend that when traveling 45 mph (70 kph) or slower that you open the windows or vents to create a steady airflow that'll give your car a cool boost. When going faster than 45 mph, however, you should dial up the AC instead. This way, you'll avoid the drag generated when windows are left open during high-speed travel.
  • Avoid auto heat-up in the first place: Other actions like parking in the shade, tinting your windows, and putting up windshield shades (when parked, of course) can help lessen your reliance on the AC when the mercury climbs.

Treat yourself to something special from savings recouped from your air conditioner vigilance. This something may be directly related to your AC-less lifestyle—spray mist bottles, a new stick of antiperspirant, a Super Big Gulp—but at least it's not money spent on gasoline.

While you're at it there are other easy ways to improve fuel economy and reduce your environmental tire mark: try to give the gas pedal a rest, say adieu to that excess junk in your trunk (or on your roof), cut the engine while at a standstill, and treat your car to routine automotive maintenance to ensure that everything is in proper running order.

Using your car's air conditioner conservatively helps you go green because…

  • It helps you consume less fuel and, in turn, saves you money at the pump.
  • It helps to diminish the emission of ozone-depleting carbon dioxide and other harmful greenhouse gases.

Automobile air conditioners—host to refrigerants like HFC-134a that are also harmful greenhouse gases—are responsible for more energy used than any other auxiliary car part. In total, vehicle air-conditioning units consume around 7 billion gallons of gasoline per year (around 16 million metric tons of carbon equivalent or MMTCE). Additionally, refrigerant leakage accounts for 8.7 MMTCE. It would require around 68 million acres of pine forest (around 30 times the size of Yellowstone National Park) to sequester the combined carbon emissions of gasoline and refrigerants.[1]

When navigating through in-town traffic, running an AC unit can reduce fuel efficiency by as much as 12 percent.[2] However, during high-speed highway driving running the AC on a low level or opening the vents can be beneficial as open windows can increase drag and negatively affect mileage.


  • automotive fuel economy: Fuel economy in cars is important because carbon dioxide emissions are directly related to the amount of fuel burned. "Miles per gallon," or mpg, is the way most Americans measure fuel economy, while other countries may use liters of fuel per 100 km traveled. To measure your fuel economy, fill your tank and reset the odometer. At your next fill-up, divide the miles traveled by the amount of fuel needed to refill the tank. For the 2008 model year, the EPA has updated its fuel economy test to reflect today's higher speeds, increased use of air conditioning, and other factors. In many cases, the published "window sticker" mpg values will be lower.

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