What is most efficient way to get the best mileage out of your cars engine, driving with the windows down, no A/C or using the air conditioning with the windows up? The answer will surprise most people.

Not only is it more fuel efficient to drive with the air conditioning on than with the A/C off and the windows rolled down, because a car uses less fuel to run an air conditioning system than it will use regarding the aerodynamic drag on a vehicle when its windows are open. But, you can expect longer overall engine life, avoiding the need to locate a good replacement engine.

The use of any automotive air conditioning system increases the load on a vehicle’s engine, which in turn consumes more fuel. The National Renewable Energy Laboratories (NREL) estimates that standard automotive air conditioning systems account for approximately 5 percent of a vehicle’s fuel usage each year in the U.S.

But for today’s drivers, just properly using the air conditioning controls and driving sensibly will help reduce fuel consumption.

Here are some tips to using a vehicle’s air conditioning system more efficiently:

When entering your vehicle and it has has been sitting in the sun, open
the windows for few minutes to release the hot air out of the vehicle. Then close
the windows and let the air conditioning cool do it’s job.
– Engage the recirculation button to allow the recirculation of the
passenger air back through the air conditioner. This button may be labeled
as “MAX.” Use of the recirculation feature will significantly reduce the
energy used by the air conditioning system.
– For a manual system, it is most efficient to keep the temperature
control in the full cold position and use the blower fan setting to adjust
the amount of cooling. The temperature control should be used to adjust the
air only after the blower is at the lowest setting.
– If the A/C is not as cold as it used to be, have an air conditioning
specialist evaluate and repair the system. If there is a leak in the
system, it should be repaired and recharged with refrigerant. It is also
normal for the A/C system to lose small amounts of refrigerant by
‘breathing’ through hoses and evaporation. This may require a recharge of
refrigerant.

Besides optimizing a vehicle’s air conditioning system, drivers can also park under a shady tree, use a reflective sun shade or leave the window partially open during sunny days.

These elementary steps allow the cars air and seats to stay somewhat cooler, which helps the air conditioning reach the cooling comfort level easier and save fuel.

Now you know how to stay ‘cool‘ and get maximum fuel economy and reliability from your car’s motor. Combine it with good old fashioned common sense and perhaps you can keep your car long enough to get the type of mileage you expected to get out of your cars engine.