Anonymous asked in Cars & TransportationCar MakesToyota · 1 decade ago

Prius Hybrid heat source?

On a Prius when the car is running on the battery where does the heat for defrosting and comfort come from? Is there an electric heater to maintain heat in the winter or does the heater gradually blow only warm to cool on battery power?


Thanks for the info. Was a little curious. I live in a cold area and wondered about where the heat came from when the car was on battery.

5 Answers

  • Anonymous
    1 decade ago
    Favorite Answer

    there is a "heat and storage tank" that keeps hot coolant with its own water pump. there are 3 water pumps in this car FYI. it pumps this hot coolant through your heater core, and that's how you get hot air in your face and windshield defrost.

    hope this answers your question.

    Source(s): work for toyota.
  • 1 decade ago

    Most of EV cars have electric water heaters that operate off the traction battery pack. They heat the small amount of water from a seprate tank that travels through the inside heater core (in the the cabin heater or defroster), then back again via a small electric water pump.

    The other type of heater is a creamic type, which is a a type so safe heating element, which is also fed by the traction battery pack voltage. This type of heat uses no water.

    Once the engine is running, another way to get heat in the cabin water heater, is with a simple heat exchanger, or two cores placed together. This is just another type of system that may apply to reuse the gas engine heat.

    Hope this helps!


    Source(s): Me head!
  • 1 decade ago

    Which Prius are you asking about? The NHW11 (2001-2003 "Classic" sedan) or the NHW20 (2004-current hatchback)?

    On the NHW11, the AC compressor is directly powered by a belt off of the gasoline engine. For the AC compressor to run, the gasoline engine will also run. (So, in the heat of summer, the engine may come on more often than otherwise just to power the AC compressor.) However, unless you have the front windshield defroster/defogger position selected or the MAX AC button pressed, the AC compressor does not run full-time/constantly (the ICE always on). (The AC compressor is used for the front windshield defroster to dehumidify the air blown at the windshield.) The AC compressor may be used if you have the AC button on, but not always. If at a stoplight, for example, and the cabin is already at/near the desired cool temperature, the ICE will still shut down, and the fans will continue to blow the remaining cold air into the cabin. When the air being blown into the cabin or the cabin itself gets too warm, the ICE may turn on (even while the car is stopped/idle) just to power the AC compressor. The AC compressor/ICE will cycle on/off as needed to maintain the coolness of the cabin.

    On the NHW20, the AC compressor is electrically driven by power from the hybrid traction battery. So, the gasoline engine is not required to power the AC compressor. However, should the charge of the hybrid traction battery become too low (say from a long time stopped while the AC is on), the gasoline engine will be restarted just to recharge the battery. But the ICE use is independent of the AC.

    Depending on your country and region, your Prius may have some small PTC (electric) heaters to help with some cabin pre-heat (though it is barely noticable). However, all of your cabin heat on either model Prius comes from the conventional source - "waste" heat generated by the gasoline engine and stored in the engine coolant. The Prius' engine is rather efficient, as it only runs as necessary, so there isn't a whole lot of waste heat, so the ICE may come on every so often just to provide heat for the passenger compartment (and also to warm itself and emissions components up). Again, it shouldn't be constantly on, once the car and the cabin are up to the set temperatures, but should cycle on and off. (There's some residual heat left once the engine shuts down at a light or such, so the fans keep circulating this heat, but once it gets too cold again, the engine will come back on to provide more heat.) So yes, if on electric-only, it'll blow warm to somewhat cool air, but once the air starts getting cool the gasoline engine will come on again to provide more heat, so the cool air won't be there that long or that noticable. You'll stay nice and toasty warm as long as your car has gasoline in it.

    North American NHW20 Prius do have the CHHS (coolant heat storage system). When you turn the car off, a small amount of hot engine coolant is pumped into this device, a flask similar to a Thermos bottle. This hot coolant is stored for the next engine startup, and then returned to the rest of the coolant. This is done to speed up the engine warmup process at startup, for lowered emissions.

    Typically, those who live in colder climates usually report lower fuel economy in the winter due to heater use as compared to mild summers. Meanwhile, those who live in warmer climates usually report lowered fuel economy in the summer due to AC use as compared to mild winters.

  • behl
    Lv 4
    4 years ago

    Toyota Prius Heater

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  • 1 decade ago

    The gasoline engine is the producer of the heat. This car does have a heat storage tank designed to store hot water for use when the electric motors take over. When your calling for more heat the gas engine will run more.

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