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Summer cold a/c vs. winter heat a/c.

Discussion in 'Gen 2 Prius Fuel Economy' started by Fubar1764, Dec 2, 2013.

  1. Fubar1764

    Fubar1764 Member

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    Location:
    Houston, TX
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    2008 Prius
    In Houston, we have two seasons: summer's coming, and summer's here. Typically, we go from "need the a/c on" to "need the a/c on to prevent foggy windows because the heat is on." What I noticed is that when I have the heated a/c on (always recirculating. . .yes, less efficient, but I'm not a big fan of ambient smells), the Prius chews through mpg much much more than if the cold a/c (again, recirculating. . .more efficient and no outside smells) is on. Is this perception accurate?
     
    #1 Fubar1764, Dec 2, 2013
    Data Daedalus likes this.
  2. css28

    css28 Senior Member

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    Suburban Detroit
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    Honestly, I'd never even consider staying in recirc for that very reason.

    Does the outdoors smell that bad? Use fresh air and your problem is solved.
     
    #2 css28, Dec 2, 2013
  3. dorunron

    dorunron Senior Member

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    Location:
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    Three
    You might consider investing in one of the expensive carbon filled cabin air filters. That will help with the stinky air we have down here.

    During the cooler parts of the year, I turn the compressor off (A/C) on MFD - NO LINE underneath. As long as I don't recirc, the windows stay clear.

    About the only time I recirc is if it is 100+ on those hot days just to keep the cabin feeling a little cooler.

    What is happening is this. Using the A/C year round with recirc is taxing the system since it ultimately is using more power from the traction battery. Of course we know that the ICE ultimately provides all the power including the traction battery AND when you add the heat into the mix during the cold snaps we have (like last week) the ICE is working double duty providing heat to the cabin as well as recharging the traction battery which in essence is what is causing the MPG to plummet.

    I know the filter is expensive, but you will notice a difference immediately. The cabin will be considerably fresher smelling. If you will invest in one of those, and turn the compressor off along with non recirc, the MPG should come up drastically.

    One other thing that is real important for this part of the year. Air pressure in tires, check it. Cold temps causes the pressure to drop. And finally, try your best to combine all trips into one when practical. By doing that you are reducing the amount of warm up cycles and spending more time in S4 mode.

    Don't know if I will make the car show this weekend at the coffee shop, but will try next month. I have the flu...
     
    #3 dorunron, Dec 2, 2013
    Data Daedalus and N.J.PRIUS like this.
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