Dear WW: your engineer who advised you not to have windows down when using air conditioner, had to be talking about putting excess load on the air conditioner. But I have no idea what he meant by "condenser" in that situation. The air conditioner is a heat pump, and used to use dichlorodifluoromethane as heat transfer agent. I don't know what he meant by condenser in this situation. Heat turns the refrigerant into a vapor. Compressing the vapor heats it very hot. When the pressure is high enough, the very hot gas opens a valve, and it passes into a long tube boustropheded (how do you like that coinage) into a small area, where it loses heat to the environment, and then is compressed again. In that long cooling tube, the gas would begin to condense, but I never heard it called a condenser. I suppose that the extra load on motor alternator from excess stress on air conditioner might stress alternator's capacitor, but I never heard it mentioned. Damn people who give lousy explanation, including me.