HOT WEATHER:
I ride with the windows about half mast (blow shit around too much in back when all the way down) and only use the A/C when my mom is with me.
COLD WEATHER:
Don't even use the heater either. I can just put the dial on the heat side (red zone) and the engine heat comes through the ducts without turning on the fan. Not as warm, but dosen't kill the four-banger as bad.