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Thread: Air conditioning settings for fuel efficiency

  1. #1
    Senior Member fc321's Avatar
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    Air conditioning settings for fuel efficiency

    Hi there,

    Can somebody recommend me the best air conditioning strategy to maintain goof fuel economy?

    I already have the "auto setting disabled which prevents the a/c compressor from running 24/7 and I never use the auto button. I drive with the windows rolled down when in the city except if it becomes too hot.

    When the weather is too hot and a/c is required is it best to keep it at a temperature such as 76 degrees with the fan on high? Or is it better to chill the a/c all the way at 65 (recirculated) until the car becomes too cold and then to switch to turning off the snowflake and activating (fresh air in) until the temperature becomes too hot to bear and then go back to 65 again (switching back and forth)

    I ask because I read somewhere that the a/c runs best at the coldest setting and that if you turn it to hotter such as 78 that it will use same amount of gasoline and introduce hot air from the engine to reach the 78 temperature. If that is true than it sounds like a tremendous waste

    Also quick question about rolling down the windows is it smart to roll down the drivers side window as well as the rear window on the same side of the car as me? Instead of rolling down the 2 front windows?

    Can you guys believe my car only has 9500 miles on it so far? I bought it new but in 2016 (It sat on dealer lot for over a year) and I hard-balled them into selling it to me for 9000$ (I told them take it or leave it and walked out) Than they called me next day and said "Okay, fine 9000$"


    Last edited by fc321; 03-12-2018 at 09:25 PM.
    2015 Mirage DE 5 speed Manual (no bluetooth) nickname: "Agile Grey Rat"

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    Administrator Daox's Avatar
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    Good question! A/C can really hog a lot of powah and fuel.

    For most efficient A/C use, turn it to max cold, and regulate temperature with the fan speed. Setting the temperature higher makes it mix in warm air from outside which somewhat defeats the purpose of cooling the air down as much. Using recirculate definitely helps as well as you don't have to cool down 90F air from outside vs 70F air inside the car.
    Custom Mirage products: Cruise control kit, Glove box light, MAF sensor housing
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        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 41.7 mpg (US) ... 17.7 km/L ... 5.6 L/100 km ... 50.0 mpg (Imp)


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    Moderator Eggman's Avatar
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    As for windows I open windows on one side of the car for air circulation. I use my A/C more for defrost than cooling.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 50.0 mpg (US) ... 21.2 km/L ... 4.7 L/100 km ... 60.0 mpg (Imp)


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    Senior Member Cobrajet's Avatar
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    On really, really hot days I will set my AC to 74 and use the AUTO setting for the fan. Usually costs me about 4-5 mpg.

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    Senior Member fc321's Avatar
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    Quote Originally Posted by Daox View Post
    Good question! A/C can really hog a lot of powah and fuel.

    For most efficient A/C use, turn it to max cold, and regulate temperature with the fan speed. Setting the temperature higher makes it mix in warm air from outside which somewhat defeats the purpose of cooling the air down as much. Using recirculate definitely helps as well as you don't have to cool down 90F air from outside vs 70F air inside the car.
    Cool, I will give it a shot this week. Will bring it to 65 with snowflake and recirculation and get the car freezing cold. Then will turn off the snowflake and switch the air from recirculate to fresh air until car gets too hot and then repeat the procedure.

    Its kind of like the same mentality as pulse and glide

    EDIT: Actually wait, maybe my logic is flawed. Maybe I should not switch the air to "fresh air incoming" because since the air in the interior has already been cooled I should just keep recirculating that air, right?

    On days that are not too hot I just have the fan on with no snowflake and on "fresh air incoming" because I dont want to open the windows on the Motorway. But sometimes that produces foul odors from the a/c vents.
    Last edited by fc321; 03-13-2018 at 12:03 AM.
    2015 Mirage DE 5 speed Manual (no bluetooth) nickname: "Agile Grey Rat"

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    Senior Member 01-7700's Avatar
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    Dang. I'm still waiting for the day I can turn off my home heating system and not have to worry about pipes freezing.
    Skills: Cage fighting, computer chatting, making sweet moula

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage 1.2 manual: 37.5 mpg (US) ... 16.0 km/L ... 6.3 L/100 km ... 45.1 mpg (Imp)


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    Eggman (03-13-2018)

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    Administrator Daox's Avatar
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    Quote Originally Posted by fc321 View Post
    EDIT: Actually wait, maybe my logic is flawed. Maybe I should not switch the air to "fresh air incoming" because since the air in the interior has already been cooled I should just keep recirculating that air, right?
    You are correct. Leaving it on recirculate will be better as you pulse and glide the A/C. Otherwise, you are pushing the already cooled air out of the car with the 'fresh hotter air'.
    Custom Mirage products: Cruise control kit, Glove box light, MAF sensor housing
    Current project: Developing a rear sway bar alternative

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 41.7 mpg (US) ... 17.7 km/L ... 5.6 L/100 km ... 50.0 mpg (Imp)


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    Moderator Eggman's Avatar
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    Quote Originally Posted by 01-7700 View Post
    Skills: Cage fighting, computer chatting, making sweet moula
    Thanks for updating your signature.


        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 50.0 mpg (US) ... 21.2 km/L ... 4.7 L/100 km ... 60.0 mpg (Imp)


  10. The Following User Says Thank You to Eggman For This Useful Post:

    01-7700 (03-13-2018)

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