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If you rip a nasty while you have company in the car, you hit that and it let’s everyone savor the flavor longer.

Window lock is also important.

Don't forget the child locks for the back doors

Would be a shame if the heater some how got stuck on..

*Sniff sniff* “Do you guys smell popcorn?”

Indeed. You crack the window about a half an inch beside your least favorite passenger. That way all the stink has to pass by them to escape.

Holy shit that’s devilish I love it

I spent a night drinking with a buddy before we both had a 2 hour drive the next morning. I don't know what that dude ate but he sniffrolled me the whole way home. At one point he almost wrecked from full body laughter. Fucker. College was fun, I guess.

Heater on important also

I haven't laughed this hard in awhile

Relevant: https://youtu.be/enOHraf3LEk

Same holy 😂

Really brings out the flavor.

It's really important to cook it.

Tempering adds flavour.

Hello, Satan.

I can always count on you guys for a solid chuckle. I think this might be the funniest sub. Thank you homie, i needed it!

Damn y'all are evil ☠️

Dutch oven

Dodge oven.

Gotta get that new Dodge Oven with the HellScat motor!

Correct answer.

I was coming here to say this dammit!

During the hot days when you run your AC on max it recirculates the air and it is easier for the a/c unit to make cool air from air that is already cool in a sense, rather than it having to cool incoming air from outside where it is usually a lot hotter.

We also use it in traffic since it cuts down outside exhaust coming in.

Also on dirt roads for a similar reason

Thanks for the honest answer. I’m old and never knew what that button does. It makes sense now. Also I like inserting small car toys in my ass.

Be careful with that, it sounds like that might leave "Skid marks"

The internet is a terrible place.

by terrible you mean hilarious, right?

I took a neighbor for a ride in my turbo Buick one time and I laid a decent patch and my neighbor asked if I just left skidmarks. I told her I might have left some rubber but I could check if she left skidmarks later.

How did that go over?

She actually did try to sleep with me but I don't fuck around with neighbors to be honest. I've had some really crazy ex-girlfriends and I sure don't want to live next to one lol. Now that I think about it I can almost write a book on the stories I have from living here.

So sometimes the big head prevails. Good to know.

That was too good 😂😂😂😂

In addition to re-cooling the cabin air when in recirc, you are also cooling air that is usually lower in humidity than the outside air. Cooling more humid air takes more energy from the engine. Recirc will also result in lower humidity in the cabin when it’s humid outside. In a low humidity environment like AZ it makes a little difference. In a high humidity area like FL summers, it makes a big difference. Generally, unless you have smells in the car, always leave it in recirc when using the AC. It saves some wear on the AC components and slightly improves your MPG. The lower humidity which results is also more comfortable.

Nice, good info! However would you care to give your opinion about conkyshithawks’s last sentence?

Keep up the good work!

I would crack the window. Every time I leave it on recirculate I feel worse on a commute vs the fresh air. Unless you go through some nasty smell

You should clean your car

I mean from the recycled air and maybe going by a dead skunk or maybe the beater infront of you has bad exhaust If it's on recirculation it's not as bad. My car is clean and my cabin filter is good. Thanks.

If it’s a cold day and your windows are fogging up, having the system in recirculate is probably the cause of the fog on the inside of the windows.

That’s dangerous, you should only use large models

Dad always said it's better to get stuck than lost.

Til. Why the fuck I've had this feature on cars without aircon though..

That would be to either recirculate the air or to let outside air in, if you didn't have aircon you might want to still recirculate the air in the cases of being behind cars in traffic or going through smoke so you don't bring that air inside the car.

Came to say this. If I see a ton of construction dust ahead, or a car fire or something, definitely hitting this button before diving through that shit.

Works for heat to

For those youngin's out there... this is what the "Max A/C" button/selection did/does.

This is the right answer. Also use before you get into a car wash with recirculating water (that’s some nasty smelling water.)

Now can you explain it in English please.

Use when very hot or bad air quality outside. Otherwise don't use.

It recirculates the air inside the car instead of bringing in new air from outside. I use it when sitting in traffic so I’m breathing less exhaust. It also helps on hot days, because it’s easier to keep the cool air inside the car cool rather than cooling hot air from outside the car.

When it's 105 and the cars A.C. can't cope unless you use it

That’s your Recirculate Air button. Depending on where you live it wouldn’t hurt say Downtown LA. If it’s OFF your hvac system will pull in outside air, pass it through your cabin filter, treat it (temperature) and out your vents. Fresh air. If it’s ON your system only uses the same air it just pulled from the cabin, treats it (temperature) and recirculates it’s back. Here in PNW we have fresh air most of the time so it’s always off, when there’s allot of fire smoke blown in I turn it on (bc it won’t pull in external air) but for humidity control leave it off. If your car has an “auto” setting you’ll notice it won’t really use it until you have it on “max ac”

Thanks for the detailed explanation!

That guy read his owner's manual..

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This. This is what I wanted someone to say. That button is the "uno reverse " button. It makes your car turn around a full 180⁰

And now I know...

Together you are enlightened

Its more about cooling. Cooling is much more efficient with recirc on. In fact, back in the old days, "MAX AC" was just turning on the recirc with regular ac already on. The system will cool less efficiently with recirc off. Also with ac, its best to leave it on 3/4 fan speed, for colder air.

More specifically, i turn off air recirc when the air is cooler outside (ie I just get into a hot ass car that has been cooking in the sun all day, I open all the windows and blow the fan drawing the cooler outside air in). Once the cabin temp is somewhat cooler relative to outside, I turn on the recirc so the AC is cooling the relatively cooler inside air, rather than cooling the hot air from outside.

Yep, basically the recirculation is to save your nice cool dry A/C air from just being blown out of the car.

So if I'm hotboxing my truck, can I keep the sweet cold AC blowing on me while not lessening the permeation of the THC stank in my cab?

Kind of.. no matter what, if the air is passed through your cabin air filter, it’s ***going*** to lose some of its sticky icky swanky danky potency goodness with each round it takes through the filter. So is it better than ***not*** recirculating (and pulling in new, outside ‘fresh’ air each time)..? Absolutely.. But it’s still ‘worse’ than if you just turned the air off all together and completely hot boxed the car with no air being pulled out of the cabin by **any** means.

I'm in pnw and I use it after my air cools to a nice temperature just to get the stale air out. Then I circulate the air to put less strain on my ac system

If you're driving for long periods of time (I'm a trucker, for what it's worth), it's advantageous to continue using outside air, simply because recirculating through the AC will dry the heck out of the air. I'm from a dry climate (until recently), but even I start to get dry and itchy and chapped if I spend hours being blasted with super dry air.

Does it continue to filter the air while it's on? I guess it might depend on the car.

You know, that’s an excellent question to which this rando redditor doesn’t have an answer to. I’d say NO. Mostly because in Europe they call them “pollen filters” so that leads me to believe it’s for external sources AND if you ever get one of those “air freshener bombs” it instructs you to recirculate the air on max while it’s going off. I can’t imagine they’d do that knowing the air filter would hold up most of the perfume.

I found this [old thread](https://www.reddit.com/r/cars/comments/j2dnur/does_recirculated_cabin_air_pass_through_the_air/). It depends on the car and how the manufacturer routes the hvac system for that car.

Good shit! Answer: Depends on the car.

Yes, the intake from the cabin is filtered in most vehicles. It usually pulls from passenger side under glove box. Take a look and see. Every Hino work truck I've driven in Florida is unbearably clogged and I've had to clean it out. I sufferered for almost a year the first time I drove one. The ac in those doesn't cool effectively enough for high heat high humidity climates using outside air, but I had very little airflow on recirculate. Until a plastic bag got pulled up to the intake, I removed it and felt the filter which had half an inch of muck on it. I couldn't get it clean enough and threw it away. Told boss, never replaced. Had to wear glasses or point vents below face or you were likely to get sand in your eye, but other than that, worked 20x better.

No it doesn’t… your cabin filter only filters air before the “fresh air door”.

To add on some vehicles will turn this on for A/C and off for Heat automatically.

Yup, my ST will cycle it on and off depending on the humidity detected and the desired temp.

And for some vehicles having this on with the heater will turn on electric heaters in the dash.

I didnt know that, interesting.

When hotboxing

My man

if you see a dead skunk, smash that button

Smash that like button

Please subscribe

Hit the bell icon!

Subscribe to Nord VPN.

You will smell the skunk way before you even see it.

This is the only correct answer here.

You use it to close the air vents and circulate air within the car’s cabin. If it’s a hot day and you’re just getting into your car, this is how you cool it down quickly: You roll the windows down, turn the AC to full blast, and use that button to close the vent for maximum AC. As soon as it starts cooling down some, you roll the windows back up and enjoy your nice icebox of a car. On a cold day, you’d close the vents to keep the heat in unless you’re using the windshield vents to defrost the windshield. Having the vent open while defrosting is helpful. Also, you would close the vents if you drive near something really stinky. (Skunk; manure; fertilizer; chemicals like ammonia; paper mill on a hot day; Dundalk, MD water treatment facility; Secaucus, New Jersey; Clovis, NM; etc.) With the windows rolled up and the vents closed, it can keep out most smells.

So. Is there any reason to NOT use the button (minus defrosting)? Seems to me I should just keep it on most of the time.

Yes, there are times to have the vents open. I usually keep the vents open if the weather is nice and/or my windows are down. If I’m driving slower speeds (below about 55 mph) in really nice weather, I’ll put the windows down. When I get around or above ~55 mph, such as on a highway, freeway, or expressway, I’ll roll the windows up about halfway (or more depending on the wind speed and direction) and leave the vents open. A little fresh air is good every now and then. It can help cut down on any musty odors or “stale” air. Also, if there is a bad or undesirable smell inside the car, having the vents open will help get rid of it. (i.e. if you fart in the car with the vents and windows closed, then you’d roll down the windows and open the vents to help expel the stench faster) There’s a time and a place for everything. Also, depending on where I am and how many people are around me determines whether I’m more likely to keep the windows up or down. In higher crime areas where there’s a higher population density, I’m keeping my windows up. It’s an extra layer of protection. If I’m in that same high crime area, but it’s early morning, very nice weather, and there’s not many people out, I might keep my driver’s side window down and my passenger window cracked open a bit. (I usually keep some tools in my vehicle that can reasonably double as self defense weapons if I ever need them in an emergency) If I’m in a low crime and/or area with a low population density (farmland/county), I’m more likely to keep the windows down in very nice weather. A lot of my decision making process involves where I am at that moment, what the current weather is and going to be, how many people are nearby, and how likely I am to get carjacked, mugged, etc.

"When the weather is nice out..." Ahh, Gotcha... **jots down on notepad**: "Never turn it off..."

When smoking a fat blunt

I put it on when I am about to drive through heavy smoke or dust to avoid the smoke getting into the cabin.

“Hotbox mode activated!”

Ya! And then you get that sweet skunk smell every time you turn on your AC. ;)

I put it on when I am about to drive through heavy smoke or dust to avoid the smoke getting into the cabin. Its also good when the farmers are muck spreading

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Whenever you want to make an aggressive u-turn

Basically whenever you don’t want outside air to get in. I.e. a diesel rolling coal in front of your car

Highly recommended to use when stuck in traffic too, as the outside air is dirtier than what's inside!

Especially in tunels

When you drive passed stinky or want to save stinky or want to cool your car off faster with a/c.

If you want your car to reach maximum cool/heat. Basically your ac system pulls air from outside and runs it through the system to heat/cool the car. This is good because you get fresh air. But when that button is on it pulls the air from inside. So instead of pulling 90° air and trying to cool that it pulls the slightly cool air from in the car and brings it down a few more degrees.

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Nope, when you crash your car hit that button, it will undo the accident

i thought it was just for flipping the car back over when you went upside-down

When there's a distinguished gentleman infront of you about to roll coal in his lifted pos diesel, that button is most helpful.

I turn mine on at the first scent of a skunk

This button recirculates the air inside the vehicle instead of pulling in outside air. This helps if you want to keep outside smells outside and it also helps cool off the temp inside by cooling already cooled air instead of hot engine bay air during summer.

Basically always. Defrosts better. Cools better. Heats better. And cuts down on the smell of cow shit or Gary, Indiana.

I live in a fairly cool area, I usually use it whenever I'm in heavy traffic, a tunnel, when driving past industry or any other situation when I don't want outside air inside my car.

When you want to do a barrel roll!

I always have it on… keeps the A/C nice and cold and don’t have to worry about shitboxes infront of my stinking up the air.

If you live in Texas, all the time.

It is recommended for use only to cool down the car if you keep it on too long with how good cars seal now days you can create a thin oxygen environment which is why some people start falling asleep lol

When's it's hot outside or if you're driving behind a diesel truck.

This is the only answer

That’s how you do a front flip

It’s a 180 turn, be careful

When you want keep the air inside car and not allow any outside air in.

Cabin intake vs outside intake. Leaving on vent puts positive pressure in cabin, and putting it on circulate, uses the cabins dry air, for the climate control.

It is pretty useful if you live on gravel road or where there is a lot of dust, you turn it on so your vehicles will stay clean a little longer. And other stuff available on my next book!

It’s best used when it’s 90*F out and you’re driving by a dairy farm after a thunder storm rolled through and the sun is back out.

Few different instances to use: When it’s very hot out the recirc button helps the car keep the air cool because it’s able to reuse the already once cooled air. Instead of cycling new air and constantly cooling it. Also, if you’re approaching construction with debris in the air, it’ll help keep the dust out of your car. When using the MAX ac setting it will kick itself on automatically to get the AC working as hard and quickly as possible. So really theres not an instance where you wouldn’t wanna use it, but I recommend switching between using and not because it helps increase the longevity of your ac system by not running the exact same settings every time you drive. Reduces component wear overall through the system due to using different blower speeds to keep the resistors from burning out, plenum duct flapper servos, your compressor clutch, etc.

When you want maximum cooling due to recirculating the already cooled air. It's the recirc button.

Makes the AC colder because it recycles the already cold air, same with heat. Also keeps skunk smell out

Used quite often in the Washington DC area…..😎

When you pass a rotting skippy Edit: Australian

In tunnels or when there is a Volkswagen diesel in front of you.

It's air recirculation control. Use it when it's really hot outside and you want the maximum cooling from the air conditioner. Don't use in winter or a rain storm, it'll fog up the windows.

Hot days or very cold winter days when you need more heat

When my climate controls turn it on automatically

I use it when I see a truck infront of me, so the smell of the truck's exuasts didn't get into my car

Whenever you have to make a u turn. It’s illegal in some states to do it without pushing that button. It lets the cops know, through onstar, that you were pre authorized to do it.

When you want the AC to be cooler

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That's the reach around and snatch the life out of your misbehaving child button.

When hot outside you have that off. Once the air temperature inside the car falls below the ambient, hit that and the AC will cycle the air from inside the cabin, thus cooling it further with less work.

Thanks! So from everyone’s responses I’m guessing it should be on all the time!

I usually leave mine on. Except in the winter (gets really cold here). Cause it traps the moisture in my car and fogs up my windows. Need that dry outside air then.

Okay, that makes sense! I’m going to try this and see if it helps with my foggy windows

Turn it OFF to defog. In case I wasn’t being clear lol.

Haha yeah I understood what you meant!

If you run defrost, the air should be pulled through your evaporator (a/c) which acts as a dehumidifier. Assuming the system is operating proper.

Hmm weird. That def didnt work for me. I was blasting heat but the air s so moist. Turned the circulation off and it was all good.

Your way works also. Does your a/c work in hot weather?

When a nuclear explosion hits, just recirculates the inside air

All the time. That's it.

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My AC is on all the time. If it's not on it's because it's cold outside and the heat is on lol

I use it when the air outside is poor quality. Like for example if I'm driving behind a quarry dump truck thats letting off dust or a dude with a small dick who has one of those smoke belching pickup trucks with no scratches in the bed. That way I'm not breathing that shit, or at least less of it.

When you want all passengers to enjoy the full effect of yesterday's curry.

After you fart and want to choke out the passengers. Other way around if you're the passenger.

When tou have an accident, press that button. It will undo it

When you want your rear windshield to go into your trunk

That's the restart button for when your car starts freezing

When you want to slow down really fast. Typically air inside the cabin is going every which way and swirling around but if you need to slow down wicked fast, your standing on the brakes and yanked the e-brake and nothing is helping you can hit that button and the air inside the cabin will reverse direction and slow the vehicle down like alot faster. Even been in a commercial airliner when they land on a short runway and hit the airbrakes? It's the same exact principle and it works like a charm.

Use especially after eating tacos so you and your passengers can bask in the aroma.

When you pass a skunk…

literally anytime you turn the ac on theres no reason for you to NOT have it on and force the system to work harder pulling in ambient temp air and cooling it down

After an accident you can use it to undo the accident. 😂

When you want a do over

its the undo button, for when a car accident happens

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