Hey I don't see any loading on my engine when I turn on my AC - I guess it depends on the BTUs that they put out but the Office AC unit I have in the office takes about 500-600 watts which is less than 1 HP so I have a hard time seeing where all these "losses" are coming from - going to.
Mehbe a/c has become much more efficient since my time. In my mom's car the idle will jump up 3-400 rpms when a/c comes on, 250 when the wheel gets turned, *shrug*
Yeah that sounds like it - the variable scroll compressor in my xB is probably a very light load on the motor and the output is not as many BTUs and the power steering is only providing a little assist at low speeds and is variable assist controller by the computer. When I was under the xB changing the oils I saw the computer control input to the pump.