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any tips on auto A/C?

Discussion in 'Gen 3 Prius Main Forum' started by jbpersmail, Apr 4, 2011.

  1. jbpersmail

    jbpersmail Junior Member

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    on cars with manual a/c, before the weather gets too hot/cold, i could leave the a/c off, set the temperature dial to hot/cold, set to allow outside air to come in, and drive around without the a/c turned on. of course, if the weather gets hotter/colder, eventually i need to use the a/c.

    not sure but i think the temp dial setting affects how much of the outside air that are coming in is actually passing through the engine compartment (to be heated) before reach in the cabin. if u set the temp dial to coldest, no air is passed through the engine compartment. this works great on a car with manual a/c.

    how can i do this on a prius? specifically, how can i adjust the temp without a/c being on? my workaround so far is to turn on the a/c, adjust the temp, and turn off the a/c. is there a easier way?
     
  2. sophie999

    sophie999 Junior Member

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    I would love to know this also. So far, I am doing the same thing as you do.
     
  3. adamace1

    adamace1 Senior Member

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    You can use the AUTO with out using the ac. Just make sure the auto button light is on and the ac button light is off.

    The auto button/function is only auto for the fan, so if you got the temp set to 70 and the inside of the car is 80 and the ac button is off the car will just blow alot of outside temp air on you to try to lower the temp to 70. Just because you use auto doesn't mean the ac needs to be on.
     
  4. jbpersmail

    jbpersmail Junior Member

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    yes but that means the fan is running.

    the method i talked about earlier (turn on a/c, adjust temp, turn off a/c) still allows outside air to come in without the fan.

    this time of the year where i live, it would be perfect to allow out side (heated) air in in the morning, but to allow outside unheated (or natural air) to come in on the way home (without opening windows).
     
  5. adamace1

    adamace1 Senior Member

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    Well you said "a/c" not fan. You need to replace all the a/c with fan. I was answering your question.

    i have no idea really what your asking. I do know if i leave my car on fresh air setting the one with a arrow coming into the car, and turn the fan off some fresh air will come in the car still.
     
  6. jdcollins5

    jdcollins5 Senior Member

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    As adamace1 said, turn Auto on, A/C off plus raise or lower temp setting until fan turns off.
     
  7. tumbleweed

    tumbleweed Senior Member

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    Not sure exactly what the question is but maybe this may help:

    Push Auto then set the Mode for wherever you want the air to go and set the temperature. Then push Off and the air will still go where you have it set and it will heat the air if the car is colder than the set temperature. The fan and the AC will not run.

    To get the mode back to Auto again just push Auto then if you go to Off the mode will operate in auto but there will be no fan or AC.

    As stated above it you turn the AC off it will stay off until you turn it back on. The Auto button returns the mode and the fan to automatic.

    The system is totally versatile but like all auto climate control systems it has its own nuances. It's very easy to operate once you become familiar with it.
     
  8. qbee42

    qbee42 My other car is a boat

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    The Prius is a very aerodynamic car. As such, ventilation doesn't work well without a fan to move the air. Older boxier designs pushed so much air that any open vent would do the trick, but not so with the Prius.

    Don't be concerned about using a fan to move air. It consumes very little power.

    Tom
     
  9. jdcollins5

    jdcollins5 Senior Member

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    I have found, with a lot of trial and error :), that leaving the system in Auto and just setting the temp works best with this system. It does a really good job.
     
  10. chrisj428

    chrisj428 Active Member

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    ^This
     
  11. jbpersmail

    jbpersmail Junior Member

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    thanks everyone, this really helps. sorry for my wording in the question.

    i was concerned about leaving the fan on (with or without a/c) - it appears that if the system is set to auto, the fan is always on (although at varying speed). i was wondering if there was an easier to to adjust the temp of air coming in with the fan off - my current workaround is to turn on the a/c, adjust the temp, and turn off the a/c. based on what i am reading, there is not an easier way.

    i followed your suggestions, and like most of u said, leaving it in auto appears to be the best. i just have to get use to it. today on the way home, the outside temp displayed 73 (but the inside car feels more like 88), i set my a/c temp to 72, thinking that would cool the car, the fan went to maximum, i later realized that i could set temp to 82 and still feel the cold air from a/c coming in, with low fan speed. very cool.

    thanks again
     
  12. RRxing

    RRxing Senior Member

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    Ditto...
     
  13. Roland1555

    Roland1555 Senior Member

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    You'll find that with this car, setting the system to your comfortable temperature setting with either the dash button, or steering wheel button is all you have to do if you set the system mode to AUTO.

    You can over ride the recirculate funtion when you like, example behind a smelly truck or old car spewing out blue clouds of oil smoke.

    In AUTO, the car will vary not only the fan speed to get you to that desired temperature you set yourself, faster, but it will also vary the speed of the a/c compressor under the hood, open and close vents as it needs to etc.

    The a/c runs on electricity, unlike your old car that used a belt and would create more drag on the engine and not always be that great in stop and go traffic where engine speeds being slower could compromise the belt driven compressor.

    In your Prius, you will not notice engine drag, and the system will run well at low speeds plus the hit on your gas mileage is super low.

    Roland.
     
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  14. twittel

    twittel Senior Member

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    JD, I see your average MPG is 48. Mine is 55. I never use "Auto"; you do. Is it possible that auto pulls down MPG? I don't know why it would. I suspect our differences are types of traffic, terrain and driving habits. I'm just thinking out loud about the whole auto thing.
     
  15. jdcollins5

    jdcollins5 Senior Member

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    Tom,

    The bulk of my driving is a 52 mile RT commute with mostly highway driving at 60 mph. My mpg is more affected by weather than anything else, wind, rain, cold etc. I would not see where Auto or Manual would make that much difference with my commute. I do see a small hit during the summer with AC, though.

    Dwight
     
  16. pictone

    pictone Junior Member

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    I too find this whole "Auto" thing on the Prius confusing. In my 2007 Sonata, Auto meant set-it-and-forget-it. Set the temp four years ago and never touched it again. Based on temp and humidity, it would automatically turn the A/C or heater on and off. As it should be.
     
  17. bnaccs

    bnaccs bnaccs

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    I also have a Subaru with auto climate control. It will automatically turn on the A/C to get the temperature down if needed. I hit auto in my Prius and waited for it to cool down. I guess that if it is 80 outside and you want it to be 70 inside the car you have to turn on the A/C, but should I use auto mode or just adjust the fan myself? Also how much does using A/C in the Prius lower your MPG?
     
  18. tumbleweed

    tumbleweed Senior Member

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    I think the Prius will do exactly the same thing for you, select Auto, set the temperature, and turn the AC on. It will remain in that state and use the heat or AC as needed to keep the temperature where you have set it.

    All the control inputs we have mentioned on this thread are for people like me who want to control it themselves. Sometimes I do what you mentioned, set it and forget it.
     
  19. twittel

    twittel Senior Member

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    I never use auto because I like the flexibility of manually selecting fan, temps, modes, windows, etc. Someone asked how much of a MPG hit will a/c cause, but I'm thinking not enough to be concerned. One of the ECO mode advantages is the a/c compressor management; i.e. on/off as needed; whereas NORMAL model keeps compressor on.
     
  20. SageBrush

    SageBrush Senior Member

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    Right. My two deviations from this are to let the ICE warm up in the winter before I turn AC on, and to let the car ventilate before using AC in the summer.

    If I am in MPG obsessive mode in the winter I initially drive with the windows open a bit to keep the front windshield from fogging. This works in my (usually) low humidity climate.