Window Fogging in Cold

Discussion in 'Prime Main Forum (2017-Current)' started by JJgrubs, Nov 14, 2019.

  1. JJgrubs

    JJgrubs New Member

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    Umh ok lots to take in.

    So for now I will stick to recirculation on, AC OFF, manual for Max heat. If that begins to fog a bit (and it will), turn recirculation OFF. And if that's still not good enough, change airflow direction to window, which turn on the compressor.

    Why would Auto be less efficient btw? Because it might choose to target windows, turning on Compressor, when I might not want it to/might not be necessary? Or because it might turn on the AC (compressor) without even targeting the windows at all?
     
  2. Salamander_King

    Salamander_King Senior Member

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    That's sound like a plan! Everyone's comfort level is different, so you should experiment what works for you.

    Again, I don't have a hard number to compare, but I had my car climate system set with AUTO 70F A/C ON all the time for my first two winter. With this setting I never had to play with climate setting. It was always comfortably warm except when first start the car in the morning, and I never had the fogging problem you are having. But for those two winters, my Eco Diary A/C load ratio was well over 20%, sometimes over 40% and I was only able to get 18 miles of EV drive out of a full charge. I think mostly because a large portion of the battery power is used for the HVAC system controlled by AUTO setting. I am trying for the first time this winter to use the manual setting to see if I can extend my winter EV range.

    For one thing, AUTO setting always tries the quickest way to warm up the cabin, that means when you first start the car, it uses full blast of fan with warm air and then as the cabin get warmer, it gradually lowers the fan speed. I have found manually restricting that fan speed to 2 seems to be more comfortable for me and dose not take much longer than AUTO setting to warm up the cabin. For one thing I never hear that blasting fan noise of max speed. When I figure out the ScanGauge setting and do some experiment, I can come up with more solid answers to support my inclination for manual mode being more frugal than AUTO mode.
     
  3. Tideland Prius

    Tideland Prius Moderator of the North
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    For the Gen 3, the manual claims the A/C compressor doesn’t run below 3°C which doesn’t make sense to me since it can rain as low as 0.5°C along the coast so fogging is still a potential issue.

    but following that logic, the temperatures you listed makes sense.

    Friends joke that I run the A/C compressor at -30°C (cause the A/C light is on in AUTO mode) but they don’t realise it doesn’t run at those temps anyway so having the light on or off makes no difference in operation. They either don’t have automatic climate control in their cars or they don’t know how ACC works.

    Sounds like a solid plan. Just experiment and see what works for your situation given our suggestions.
     
  4. Salamander_King

    Salamander_King Senior Member

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    One thing I am not clear is what temperature sensors those modes are using to turn on or off. Is it ambient temperature outside or inside cabin temp, or evaporator or condenser? Of course, my car parked outside, the first thing in the morning the temperature in all of those sensors is same as outside ambient temp, so at startup it shouldn't matter. But after the car is stared, I don't know.
     
  5. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    I appreciate this is a Prime discussion, maybe some variations, but recirc is something I'd never turn to, when it's fogging up. Rarely if ever use it, fwiw.
     
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  6. Salamander_King

    Salamander_King Senior Member

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    I am with you on this one. I like to breath fresh outside air coming into the cabin. But hey, maybe Recirc will cut down the car's total CO2 emission? LOL:LOL::LOL::LOL:
     
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  7. ice9

    ice9 Member

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    You might also try turning off ECO AC. I haven't had a humidity problem with it yet, but I expect that I will, sooner or later. My understanding is that ECO provides AC/heat at minimum power consumption. If you take it out of ECO mode, you may reduce cabin humidity with increased compressor operation. Also, I believe turning defrost on forces the compressor on WITH heat, which is the best combination for dehumidifying. Use defrost to get on top of the problem and then go back to normal AC/heat with ECO off, once the windows are clear.
     
    #27 ice9, Nov 15, 2019
    Last edited: Nov 15, 2019
  8. JJgrubs

    JJgrubs New Member

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    I thought recirc was generally desirable to keep the warmer air in (instead of warming up new cold air). Ditto for keeping cold air in during the summer (instead of constantly cooling off air).

    But yes, it presents a fogging problem. Hence why I opened the thread. So it's still #1 choice for short trips. But for anything longer than 10 min, I have to use the other choices I outlined above.

    Thank you very much for the help guys really
     
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  9. The Electric Me

    The Electric Me Go Speed Go!

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    I've got some cast iron pot over an open fire advice here.

    But you can prevent a level of fogging and speed up defrosting and fog removal by doing two basic things that don't have anything to do with switches, compressors, fans, or intake vent selection.

    Check to make sure your window seals are good and your windows are closed firmly and tightly.
    Secondly...even if they look clean? Clean and dry the inside of your windows thoroughly.
    Any substance on the inside of your window will trap moisture and create fogging and make it take longer for your windows to clear.

    Sometimes I'm amazed at the difference in how long it takes my windows to clear after I clean the interior side of the windows.

    There are also anti-fog products available. But I've personally never liked them, or had much success with them.
     
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  10. NSXT

    NSXT Member

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  11. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    I find this window cleaner very effective:

    Glass Kleen Industrial-Strength Glass Cleaner, by kleen-flo

    Available for me in Canada at Princess Auto, not sure about the States. Website info:

    Kleen-Flo | Products - Glass Kleen
     
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  12. The Electric Me

    The Electric Me Go Speed Go!

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    If you read the "Bob is the Oil Guy" thread. There's a lot of skepticism about the effectiveness of this approach, with a lot of people suggesting "store bought" drying agents...or silica packets.

    In the Vila article, the rice is to be gently/slightly heated and then rubbed against the inside of the window. And the Villa suggestions are MUCH more about de-icing and de-frosting windshields as opposed to preventing fog or de-fogging.
    Defrost vs. Defog are really two separate challenges.
     
  13. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    About on par with the box of baking soda in the fridge? At some point you become a rebel: chuck it out and don't replace it, boohaha.
     
  14. NSXT

    NSXT Member

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    I know they are 2 different things but it can be used for either ways.

    So you know, I have already been using this method many years ago and it does defog less inside my cabin during raining/winter time. Either my brain is simulating and telling me it is a hoax but it is working for me :ROFLMAO:
     
  15. JJgrubs

    JJgrubs New Member

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    Quick update.

    Most days, I can keep recirc on, with heat, AC off, and direction towards me (not windows). This doesn't always fog.

    Today was the first time it started to. So I turned recirc off and redirected airflow to windows and it worked excellently. Defogger really quickly actually. No need to click on the Defogger itself, which just turns on my gas engine.

    Thank you very much, incredibly helpful stuff.
     
  16. Tideland Prius

    Tideland Prius Moderator of the North
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    Thanks for the update! It's always helpful (especially for someone in the future to read through this thread and then see the solution or outcome)
     
  17. The Electric Me

    The Electric Me Go Speed Go!

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    Who am I to say?
    Since I've never done it.

    I think I'll pass on the sock filled with rice under the seat trick however.
    I picture myself trying to explain to "Law Enforcement" what the strange sock filled with an unknown substance is doing underneath my seat.
     
  18. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    I'm pretty sure that "film" that develops on the inside of windshield, makes for more fogging up.

    I find it helps to clean it every fall, with the aforementioned Glass Kleen. I use one of those paddle cleaning brushes on the inside, spray the cleaner on the paddle. Doesn't take much.
     
  19. Old Bear

    Old Bear Senior Member

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    When the front windshield defroster is activated from the buttons to the left of the display, the Prime will start its internal combustion engine to produce a lot of warm air rapidly. The engine will then run for enough time to warm up its pollution controls even if you turn the defroster off.

    I have discovered that under most circumstances, I really don't need that blast of hot air and that simple air circulation will adequately clear fog on the inside of the windshield. This can be done by using the fan control on the touch screen. Once the windshield is clear, the fan can be turned off by touching "OFF" on the screen.

    [​IMG]


    Of course, if the fogging is happening on the outside of the windshield, and the windshield wipers don't clear your view, you really need to use the engine to heat the windshield glass.

    Note: The rear windshield defroster/defogger operates using electric heat from the grid embedded inside the glass and turning it on or off will have no effect on the internal combustion engine.
     
  20. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    It might help if Toyota provided a regular vent mode were all the air was directed to windshield.
     
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