If you want to save fuel, forget window vs. AC, the obvious solution is: drive 100km/h rather than 130km/h.
Although the difference seems like not that much (merely going 25% slower), you need 2.2 times as much energy to drive 130 instead of 100 km/h. Velocity is the single biggest deciding factor in the equation, as it's raised to the third power. Anything ...
Suppose a very hot summer day, driving on a long straight highway at 130 km/h. What is most fuel efficient solution :
Driving with AC on and closed windows?
Driving with AC off and four full opened windows?
Of several choices, those are the worst. Why are you confining your selection to those? Also, running windows-open will make you deaf.
We could make a quantitative comparison using some ballpark figures.
Power consumption of your car's air conditioner depends on many factors, including its settings and the environment. A fair assumption of average consumption is approximately 3 kW (which might be as much as a factor of 2 off). This number can be compared with The increase of air drag power ...
Fuel efficiency shouldn't be your only consideration. Rolled down windows will expose you to noise levels well above 85 decibels which can cause permanent hearing damage with prolonged exposure.
British scientists tested everything from a Mazda to an Aston Martin in non-rush hour traffic going 50, 60 and 70 MPH.
They found that regardless of speed or ...
It depends on several factors:
The car's aerodynamics
The AC compressor load
Temperature differential between the desired temp and the outside temperature
The SAE did an experiment, the full results are paywalled, but there's some useful detail in the summary:
On-road and laboratory experiments with a 2009 Ford Explorer and a
2009 Toyota Corolla were ...
Keeping a constant speed using cruise control with windows shut and ac on because once the cabin is down to temperature it requires little to keep it there and the ac will modulate its power needs.
Driving with windows open will increase the drag and that will only reduce if you either reduce speed or close the windows.