Does anybody know how much aircon actually uses - mpg wise? I've heard figures of 10% bandied about but I struggle to believe that.
It must have some effect, but less than having the windows open at speeds above 30 mph. I hate the way climate control blows the air where I don't want it and turns the fan speed right down sometimes, and when the car interior is 'up' to temperature after a few miles the vents seem to blow cooler air. I use aircon but prefer to control vents and fan myself. I actually miss the old rotary knob that allowed you to mix hot and cold air manually, and continued to blow warm air even when climate control will now decide 'right, the cabin is at set temperature, I will lower the fan and blow cooler air now'. Air blowing at you at 19 or even 20 deg C can feel cool even though the cabin is supposedly at same temperature. If you increase temp it blows warmer air for a while and then seems to cool down, I have draught detector in passenger that can detect minute changes in temperature and airflow, it has an audible alarm as well...