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?

  • Set the thermostat to a lower temperature and keep fan speed to the lowest setting

  • 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

  • Mamertine@lemmy.world
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    11 months ago

    Older cars, the air conditioning was simply true false.

    As in it was running or it was not running. You adjusting the temp warmer, just mixed more warm air into the chilled air.

    I do not know if modern cars work that way.

    If that’s the case lower temp because higher temp is just adding warm air to your cold air.

    But then we get into how fan blower motors work. Again, in older cars (I don’t know how modern computerized cars work). The blower was on or off. The fan speed knob was actually a resister that caused the fan to blow less hard by reducing the amps to the fan. I’m not an electrical engineer, but I gather the lower speed setting is consuming the same amps, but turning some into heat.

    IMO crank it. It’s the same cost no matter the settings.

    • fine_sandy_bottom
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      11 months ago

      I don’t really know anything about electronics but I don’t think resistors work that way.

      I think it’s something like creating a narrow point in a water pipe. Less water can get through so less water world be taken from the source.

      • KillingTimeItself@lemmy.dbzer0.com
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        11 months ago

        part of the reason resistors lower voltage is because they produce heat “slowing” down the flow of the voltage. Think of it like a pipe with a set flowrate and a set pressure, but you want to lower the flow rate, so you restrict the opening, which lowers the flow rate, but now the head pressure is much higher (before the restriction)

        Imagine this imaginary water source as a water pump. Now it’s burning more energy due to the flow restriction, and working against it.

        You can also calculate the heat dissipation of a resistor, and how much power it will let through, which allows you to take a mathematical approach to it. I’m not doing that though lol.