The dog days of August may have motorists reaching for the air conditioning switch in used cars in New York, and they can now do so without worrying about fuel economy.

Industry scientists say that for sedans, the aerodynamic drag caused by rolling down the windows at highway speeds robs a vehicle of more energy than putting on the A/C.

To make the process more efficient, air conditioning subunit manufacturer Delphi recommends that before starting up a car that has been out in the sun, roll down all the windows to allow hot air to escape, then roll them up and put on the A/C.

Proper maintenance may also help owners cool down in used cars in New York: air filters can become clogged and less efficient, pushing less cool air through vents to occupants. Old coolant may also cause a similar reduction in the effectiveness, noted Delphi.

In city driving, however, SUV and truck owners may want to consider not using the air conditioning feature, since the boxy shape of those vehicles will outweigh any fuel savings, reported Slate.