On a hot day and traveling in a car, which method of keeping the occupants comfortable with the A/C is more energy and fuel efficient?
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Set the thermostat to a lower temperature and keep fan speed to the lowest setting
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Set the thermostat to a slightly higher temperature and compensate by setting the fan to a higher speed so you can feel cool enough with the breeze
A vehicle AC compressor does cycle. There is a clutch on the pulley attached to the compressed that engages the compressor or lets the pulley free wheel.
Also the alternator absolutely takes more power from the engine in proportion to how much energy it’s putting out.