Does anybody know what uses less power...
1. Running A/C at around 70 with higher fan speed
2. Running A/C at 64/LO with low fan speed
The difference may be minimal, I have no idea. Just wondering if anyone knows.
The compressor uses much more energy than the fan.
It greatly depends on the outside temp. If it's 85 degrees out, I expect the 64 degree setting will use more power. If it's 50 degrees out, then I'd expect the 70 degree setting to use more power. The fan motor power is far less than the A/C or heat, but if set to low it may have to run the compressor longer, using far more energy. If the outside temp is close to the desired temp, then the compressor will not need to run, and the low fan speed will clearly take less energy than the fast fan speed.
All that said, the load even under wide temperature extremes seems to be less than 5% of the energy used when driving around - so I really wouldn't worry about it.
Can't complain about the energy usage of the AC. It seems to be a very efficient unit. Precooling the car a few minutes before you get in makes a world of difference. The defogger which uses both AC, heat and the highest fan speed is a power Hogg but it actually works now.