When it's too humid, or going to work when it's HOT, I usually cycle the A/C based on load. For example with highway driving, if I need less drag to pull a hill, I run the A/C on the downhill or level end just before the grade -- the condenser is cool, as well as the cabin. Then, with the switch "off", I run the recirculator to recycle the cool air (seems to last a couple minutes) and FE is improved on the uphill side... Then back to the downhills: flip the A/C on again to use momentum to cool instead of fuel (used where EOC isn't practical). It's generally the opposite with good EOC downhills -- somewhat level or slight downgrade: A/C on -- good hill for EOC = engine off, recirc on, fan medium. Again, no parasitic losses except for some batt drain.
Not exactly following the topic. But I figured I'd post it anyways. You can use high temperature pipe insulation to increase the effeciency of your A/C so it blows colder. Its very cheap too. Pulled this off a Pontiac Vibe forum. The initial link to matrixowners doesn't work, but if you scroll down you'll see exactly what to do.