If i want to save fuel, is it true that i can set my car air cond blower to the max n compressor to the min?

What you should do is set the temp control to a higher temp setting then the compressor will come on less and you will save fuel

Ideas like those are silly. It takes a little fuel to run the ac, but the blower motor will do nothing one way or the other. The best way to get mileage is to drive easy and keep your car maintained. The blower motor just pulls air into your car, it will do nothing to affect mileage; everything electrical runs by the voltage from your alternator, your battery is there just to start your car and provide stabilization for your charging system.

Air vent opening and fan speed is not related. As far as AC go with the seting to the max or min do not effect your fuel eco that much. However, turn off the ac and roll down the window would cost you more to operate your vehicle.

I wish I could remember the research site that studied this.
However, when you are driving running the air conditioner or not running it made no difference to mileage, running with the windows up or down made no difference.
If you are not driving then you should shut the engine off to save fuel. It is not possible to talk about mileage if you are sitting still.
One of the reasons they tell you to use the air conditioning is that if you are from anyplace with winter people tend to shut it off for 8 months of the year. The result is that the compressors seize up from not being run.
One other reason for using the air conditioner is that rolling down the windows creates a noisy air draft. Not fuel robbing, just annoying.

One of the biggest factors, second only to drivers habits on the gas pedal, is still proper tire pressures. If you want to save fuel get a pressure guage and inflate your tires to the recommended pressuer for your car. It is usually on a sticker on the drivers door.

I believe that if you set your air conditioner to the max/recirculating button to keep the cool air inside the cabin you won’t be pulling hot air from outside to have to cool and you might save gas. Running the fan on high all of the time just puts more drain on the electrical system which has some power drainage. Don’t run the system on defroster mode unless you absolutely need it because this turns on the air conditioner even in the winter time. If you don’t need defrost don’t use it.

If you drive a car that’s less than 10 years old the use of the car’s A/C is practically irrelevant when it comes to fuel economy. When you have the A/C running the compressor cycles on and off as the thermostat dictates, it does not run continuously like a lot of people think.

As other posters have mentioned, the best way to save fuel is to keep your car maintained and to drive prudently.

Another poster also says that you should limit the use the defrosters in your car. This is just silly. When the defrosters are on the A/C compressor cycles on and off in “bursts” of about 5 seconds. It does this to dehumidify the air inside the car so your windows don’t fog or frost on the inside.
This is a safety feature of air conditioned cars and the cost to operate it is practically nil.

Good luck!