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What are the typical heater/defroster energy requirements for average and peak demands in a car?

I would like to know the values in kW of the energy requirements, particularly in cold weather climates.

What if there is no waste heat for the case of an EV (Electric Vehicle). I know there are heating elements that are going to be used but what are approximate values in kW?

1 Answer

  • 8 years ago
    Favorite Answer

    The best clue I have for you is the efficient heat pump that was installed in the old GM EV1 electric car. I know that it had several settings, starting at 500 watts, and the highest setting was 1500 watts (1.5 KW). It was used for both heating and cooling.


    Traditional cars almost certainly use more energy than this, but the unit in the EV1 was specifically designed to be efficient. Electric car manufacturers also take greater care to insulate the passenger cabin well, so that it can be heated/cooled using less energy.


    Worst case: An electric car with a 120 mile range, driving at 60 MPH with the heat at maximum the full time would therefore use 3 KWH in the two hours it takes him to drive 120 miles. This implies a 30 KWH battery pack, and a driving efficiency of 4 miles per KWH. The 3KWH he used for heat would therefore use 10% of his energy, and take about 12 miles off of his 120 mile range.

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