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If you cool the evaporator down below freezing and use outside air the evaporator will soon become a large ice cube and you will lose any ac benefit. Ever have a ac that spit out a fog bank from the vents? Your evaporator will soon freeze up if your ac does that. On recirculate the ac will take the humidity out of the air inside the car. Once that is done and you are recooling the same air over and over, the temperature, at the vents will drop.
I always run my ac on recirculate, never ambient. When the car is moving the airflow over the ac condenser will make it work much better. Modern systems are designed to produce more flow at slightly higher temperatures.
My Echo seems to not cool properly, especially when you have left it in the sun and it's light blue. If it was black then it might be another story. Get it moving and that same ac gets cold enough to make my hands numb.
The old R12 systems would spit out air close to freezing temperatures, but they cost a lot more in energy to operate that way. Remember when the old York with huge pistons came on an you could hear it and feel the loss of power, even with a giant displacement engine. When efficiency became the primary consideration and no frozen evaporator became a part of the design parameters temperatures at the vents had to fall.
Also remember, no modern air conditioner is going to cool off a baked 160 degree interior very quickly. Either open the fresh air or thee windows and get rid of that temp surplus without relying on the ac alone. It gets hot enough here that I open both doors and let the car air out a little.
In my old school manual transmission Echo, I actually use forced decelerations to crank up the air conditioning and get "free" ac when the injectors shut off completely and the compressor is still running, even wit hthe engine using no fuel. In many cases where traffic congestion is significant and stop and go driving is the norm, using the ac when decelerating gives me most of my ac. without a fuel mileage penalty.