How to Turn off All Heat and Cold A/C?

Discussion in 'Prius c Main Forum' started by highroller, Mar 4, 2014.

  1. MKART

    MKART Junior Member

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    I have the same problem with my 2010 lift back. Even when I hit the "off" button, if I put my hand up to the vent I can feel a warm breeze. This bugs me when it is warm in the afternoon and I don't want any heat. I find that the air comes out at the temp you had it last set at. So if I leave the heater on HI(temperature) when I hit the off button, it will blow warm air. But if I leave the temp at LO when I hit "off", it continues to blow cool air.
     
  2. Domovoi

    Domovoi New Member

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    Thank you! I wouldn't have thought of this. My Jeep actually turned things off when I had everything off :p
     
  3. Fauxknight

    Fauxknight Active Member

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    It's not an off/on as much as simply where it allows forced air flow to go.

    Understanding the whole system is key:

    Under normal conditions both the intake and the fan force air through the system. So without the fan on there is air flow, the fan simply improves it. When set to recirculate cabin air the intake for air movement is switched to the cabin, so car velocity no longer causes forced air flow, you need to turn the fan on to get air flow in this mode.

    The temperature setting determines how much heat is drawn from the engine to warm the air flow, 'low' is none at all and 'hi' is as much as possible, with every other temperature setting being somewhere in between. Of course this is without the A/C on, when it is on 'low' suddenly becomes max cooling output rather than the nothing at all.

    So to get air flow as zeroed out as possible you need to set the temp to 'low', the fan to 'off', have the A/C off, and to set the cabin air to recirculate.
     
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  4. koipond

    koipond Member

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    "Low" turns off all heat. It also won't engage the AC unless you hit the AC button. So "low" with AC button turned off is what you would do.

    SCH-I535 ?
     
  5. Oldwolf

    Oldwolf Prius Enthusiast

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    I do a lot of highway driving and in the summer I get better mpg with windows closed and A.C. on. Also the batter cooling fan runs at a lower speed with A.C. on.

    -Tapatalk2 on Android
     
  6. Rob.au

    Rob.au Active Member

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    Nailed it. As you say, "LO" doesn't always mean off... for me, with the A/C on, it means "Arrrgh I do not care about the mileage, stop mucking around and cool this thing down NOW". It gets hot (and humid) here in the summer... an overheated cabin does not make for a happy HV battery or a happy driver. :mad:
     
  7. PriusSport

    PriusSport senior member

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    Interesting discussion.
    I asked the same question in another thread about my '13 Prius 3 more recently.
    I want to turn off the heater in the winter so it doesn't use the engine and lower gas mileage.
    The answer, I guess, is you turn the temp to the "low" setting, make sure the auto mode is off, and turn off the fan.
    There will still be some fresh air (warm?) circulated through the vents even with the fan off. You can kill this by pressing the internal only circulation button.
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    You can go too far with this quest for suffocation, lol.
     
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  9. lar.smith42

    lar.smith42 Active Member

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    Ok let me get this straight !! You guys air up your tire to the max ( so you get a rough ride) You hyper mile in traffic ( Causing a safety hazard plus giving normal Prius drivers a bad rap) You turn off AC in the summer (uncomfortable for driver and passenger and Hybrid batt.) Turn off heat in winter (Just plain stupid.) Hook up external gadget to monitor everything as your driving down the road. (should be paying att. to road). Your choice of tires has nothing to do with safety( wet traction, dry traction, hydro planing resistance, handling , Quietness) Just MPG. Anybody else see a problem here.
     
    #29 lar.smith42, Dec 21, 2016
    Last edited: Dec 21, 2016
  10. Sean Nelson

    Sean Nelson Active Member

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    I just clued into this sort of thing with the recent very cold (for us) snap here in Vancouver. I'm in the habit of setting the temperature control to 23 to 25°C. But I found that it takes forever to get the cabin warmed up to that temperature if it's below freezing outside. Much faster to set the control to "HI" and then turn it down to 23 to 25°C once it gets to the temperature you want.

    If I'm feeling particularly eco-minded, I turn the temperature down to 23 to 25°C when the car is in EV mode and then back up to "HI" when the driving conditions require the engine to run. But that doesn't happen all that often.
     
  11. Sean Nelson

    Sean Nelson Active Member

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    I believe that even in the "recirculate" position the HVAC system still admits a small amount of the air from the outside.
     
  12. Sean Nelson

    Sean Nelson Active Member

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    <tonque-in-check>Nobody else is doing it?</tonque-in-cheek>
     
  13. Sam Spade

    Sam Spade Senior Member

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    It does. It is required as a safety measure to help prevent carbon monoxide accumulation.
     
  14. PriusSport

    PriusSport senior member

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    Raising tire pressures a bit to improve mileage is common to a lot of cars. Hyper miling with nobody behind you makes sense. You get used to taking your foot off the gas on inclines and coasting. My '08 had a magical point where all the feedback lights went off--but what about my '13? No equivalent obvious, but still you can work the gas pedal to switch from engine to battery.
    What's different is the temp. setting. I now set temp to 'low' when engine is cold. The idea is to use as little engine as possible until it heats up. Worst gas consumption is on startup. After warmup, increase temp as desired. With a coat on, 65 is plenty warm. Keep the vent fan on a low setting. I figure I can get at least 50 mpg on mixed driving in winter. Haven't worked it out yet.
     
  15. Mendel Leisk

    Mendel Leisk Senior Member

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    I've just been noticing, with our 2010, half warmed and ambient temp around freezing: engine tends to run a lot at red lights, but shuts off if I turn cabin vent system right off.
     
  16. Prodigyplace

    Prodigyplace Senior Member

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    On my 2017 Gen 4 Liftback, in the Auto Eco mode for the climate control, the fan does not come on until the engine has warmed up some. Apparently Toyota is trying to use some of these tips automatically.
    On the Gen 4, climate control Eco mode is separate from the Hybrid Eco Mode.
     
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