which way of driving saves more gasoline? Open window no AC or close window with air conditionor.?

Question

my husband says the wind will slow down the car, which cause more gas.

Answer 1

With the cars that use freon the myht buster are right. the cars that use 134A as a coolant it doesn't matter. Freon using cars the a/c compressor only runs when the a/c is on thus putting more torque on the engine by having to have a separate belt to run the a/c. The 134A coolant has to circulate constantly even if the a/c isn't running. Which is why most cars now have the more fuel efficient snake belt pulley system rather than the multy belt system found on the majority of cars prior to 1994. the reason 134A needs to circulate constantly when the engine is running. Is it doesn't have the CFC's to stabilize the coolant when the engine heat hits the non-runng cooling system.

Answer 2

Aerodynamics. Smooth airflow. Drag is proportional to speed squared. Power to overcome drag is proportional to speed cubed. Anything that smooths airflow around a vehicle will reduce drag and power (gasoline consumption). The question is, how does the aerodynamic drag compare with the drag of an A/C compressor in operation? An ideal way to experiment is with a vehicle that has an instantaneous miles per gallon computer, a flat stretch of highway, and a no wind condition. There may be a speed which yields a breakeven point for an open window/windows or A/C. In my book, during the summer I use air conditioning for my personal comfort. To save gas, slow down! Even an aerodynamic vehicle is subject to the laws of physics relating to drag and power.

Answer 3

You're husband's correct. The reason is that with the windows open, the displaced air will have to be piled up against the rear window and the turbulence will distirb the aerodynamics of the car.

If the car is equipped with an a/c, there will be absolutely no difference in mileage whether it is on or off! That's because the a/c unit is driven at all times just to keep it lubricated.

Therefore, always have the windows closed, either around town or on the highway. It makes absolutely no difference if the a/c is on!

Answer 4

The Mythbusters answered this exact question by taking 2 identical cars and filling them up and driving 1 with A/C and the other without. They also repeated the test in a later episode and here's the results...If you are driving slower than 45 it is more efficient to roll the windows down. Speeds greater than 45 roll them up and turn on the A/C.

Answer 5

Run the AC on the highway. Shut it off and open the windows on city streets. Keep in mind that the discomfort in opening the windows may not be worth the minimal extra fuel used. Modern AC systems are far more efficient than they were 20 - 30 years ago.

Answer 6

55 or higher, roll up the windows and turn on the AC, the air drag is high enough to cause less efficient travel. At speeds below 55, crank down the windows and turn off AC.

Answer 7

I heard that whilst you're sitting in site visitors, you're able to open a window to save gas. I additionally heard that whilst you're on the line, an open window reasons drag which decreases gas performance. there is debate whether or no longer air con makes use of gas or no longer. some say it does, mutually as others say it would not. I in simple terms shop the homestead windows closed and turn on the fan so as to save gas and improve my mileage.

Answer 8

they tested this on mythbusters. when you run ac, you use extra belts and put more strain on the engine. when you have the windows down you create extra draft, making the car have to work harder to get to the same speed. i believe the result was that it is more economical to have the windows down. either way, you're getting worse mpg than you normally would, and the difference between ac and windows down is minuscule.

Answer 9

A/C on the freeway.
Open windows city driving.

Answer 10

open windows they did it on mythbusters