Hey all....just wondering if max a/c uses more fuel than normal a/c ?
Does it make the compressor work harder or is it just a change in blend door configuration?

Thanks

 

From what I have heard the A/C puts the same amount of drag on the engine regardless of blower speed. In other words you burn the same gas on low a/c as high a/c. If you are looking to conserve run it full blast and then cut it off when comfortable. Using it 100% on half the time is better than using it on 25% speed all the time.

 

Yeah now that I kinda think about I guess the compressor clutch is either engaged or dis-engaged.
I realize fan speed has little/none to do with milage , I don't think fan speed even changes form regular vs. max.
Ay nevermind I think I got it figured out! My brain just rebooted

 

The difference from A/C to MAX A/C is that when you set it to A/C it brings in fresh air but when you set it to MAX A/C it recirculates the air.

 

may even save fuel on max, if the compressor cycles off more.

 

Either way above 40 mph its better for fuel economy to run the a/c with the windows up than to drive with the a/c off and the windows down.
The drag caused by driving with the windows open lowers your fuel economy more than having the a/c on. There was an episode of Mythbusters about it.
They found that you got the best fuel economy driving with the windows down and the a/c off below 40 mph, but once you got above 40 mph the drag was enough with the windows down that running the a/c was better for fuel economy.

 

Max A/C is more efficient because it recirculates the cooled air in the cab instead of bringing in the hot/humid air outside. The system will also move more air in the "max" setting because the blower is located right behind the recirc. door making it easier to pull the air in.

 

I always use the max setting as it cools the cab better than non-rec. You can achieve max a/c on any other setting as well just by hitting the rec button. During the summer around here, I just turn it on max until the cab cools down, if that happens.

 

Max burns less gas because it's pulling less power off the belt because it's doing less work to keep the air in the cab cool. By recirculating, you don't have to cool/dehumidify every bit of air that passes the blower. After a few minutes, it's dehumidified (which takes a LOT of energy), and it's cooler than the outside air.

The blower doesn't have to do any more work to pull outside air, so it blows the same amount either way - it just SOUNDS like it's doing more because you can hear it on recirc. When it's on fresh, that noise goes outside.

 

Someone with an Edge or a ScanGauge should verify what the engine load is at say 60 mph with Max on vs normal a/c operation.

 

I have always liked to think that the idea Steve83 presented is right... So when its AC on, its on max. Besides-- I like it to be REALLY cold when I drive... It should be 60* in the cab. (Meaning the AC is running at about 38* to achieve this...) I hope my AC never goes out...

 

In my 03 Ex, Max air actuates a vac valve on the heater hose and shuts off flow of hot water to the heater core. This allows max air to not have to cool off blended air. It circulates internal air, making cool air cooler, and does not have to deal with any residual heat from the heater. I have e-fans that are connected to the AC. I can hear them turn on and off. I notice they staff off longer in Max air. With regular AC they stay on almost constantly.

Sometimes i throw caution to the wind and turn the AC on AND drive with the windows down

 

MAX sounds ominous. ALL it does is recirculate the air inside the cab to be cooled by the evaporator.
SO In actuallity, MAX whould use LESS Fuel.
The compressor works easier cooling a 60* inlet temp to 40* than it does a 90* inlet temp to 60*.
Also when it gets frosty cold inside the cab, The compressor will cycle off.

 

That's what the blend door is for. If it's working right (and it's easy to adjust), no hot air will blend when you set it full cold.

 

Ford designed the Max A/C to be more fuel efficient, like Tbird said. It uses less energy to cool air that has already been cooled and recirculated, therefore creating less drag on the engine.
Personally I just now have began believing that running AC is more efficient then windows down, but it is true that on the highway it will improve your MPG and power loss.
Around town though I feel is a different story, around town I believe windows down is better for power loss. However its more about comfort on those 100+ degree days.