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
The question was about keeping the occupants comfortable with minimal fuel energy. So far, this is the only answer that factors in the human element of cooling the occupants with their own sweat. Frankly, I’d take a 5F warmer day with a breeze over a 5F cooler day with no breeze. The same goes for in a car.
On a hot day, I’ll start with the windows open and AC running just to push the hot air out and give the AC a lower ambient starting temperature, but the question wasn’t about how to cool the car the fastest.