Do all 4Rs default to recirculation mode for A/C?

[Michael-Dallas]

This doesn't make sense to me. I see no reason why recirculate uses more power than when it's off. In fact, it seems the blower is working harder when it's recirculating.

When AC runs w/ recirc off, it brings outside air for the AC system to cool. Recirc closes the flap that brings in outside air. So it takes less effort to keep air that's already been cooled, cool, than to cool outside hot air.

 

[00Sebby]

This doesn't make sense to me. I see no reason why recirculate uses more power than when it's off. In fact, it seems the blower is working harder when it's recirculating.

As Michael-Dallas said, the A/C works less. The reason you think the blower is working harder is due to the louder sound it makes with the outside air door closed. It runs at the same speed based on the fan speed setting.

 

[Photogr]

When AC runs w/ recirc off, it brings outside air for the AC system to cool. Recirc closes the flap that brings in outside air. So it takes less effort to keep air that's already been cooled, cool, than to cool outside hot air.

As Michael-Dallas said, the A/C works less. The reason you think the blower is working harder is due to the louder sound it makes with the outside air door closed. It runs at the same speed based on the fan speed setting.

I admit I'm not familiar with the intricacies of these systems and you could be entirely correct, but this does not pass the sniff test.

First, when the car is sitting in the summer sun, the air in the car is hotter than the air outside. So when you first start the car the recirc air going through the cooling system is warmer. By your logic it would be better to begin the system by pulling in the cooler air from outside. But even if the air outside is warmer I don’t see the energy to run the system being increased by starting with the recirc on. What part of the system is working differently?

I agree with you that over time the recirc air should be cooler than the outside air because the system has had time to cool it. But the comment I made was regarding Michael’s post which states “ In order to reduce the A/C power consumption…..Recirc air mode is on when the engine is started…" not after running for several minutes.

With regard to when the car is first started, whether the A/C is in recirc mode or not, the temperature is set to the coldest setting. So the question to me is whether there is any difference to the cooling system, other than the air source. It seems to me the cooling temperature within the coils is the same regardless of the recirc switch, so there shouldn’t be any difference to the power consumption of that portion of the system. And, if 00Sebby is right that the fan is just louder and not working any more, that just reinforces my point that the system isn’t working any harder or consuming anymore energy.

Beyond the issue of whether the system is working harder, I have found overall the cooling system of these cars is marginal and find that it works best when running at highway speeds with recirc off. That’s just my opinion, but it seems to be true in my car. Even at city speeds, the system seems to cool better though the difference is less obvious. Therefore, the first thing I do when I start the car in the summer is hit the recirc button. I would be much happier if the setting were to remain on or off from the last use rather than having to change it on startup every time.

 

[00Sebby]

I admit I'm not familiar with the intricacies of these systems and you could be entirely correct, but this does not pass the sniff test.

First, when the car is sitting in the summer sun, the air in the car is hotter than the air outside. So when you first start the car the recirc air going through the cooling system is warmer. By your logic it would be better to begin the system by pulling in the cooler air from outside. But even if the air outside is warmer I don’t see the energy to run the system being increased by starting with the recirc on. What part of the system is working differently?

This is an assumption. If you parked in the shade or a covered parking area or a garage, the interior of the vehicle may be cooler than the temp on the road and the recir just saved all of that cooler air from being forced out of the vehicle. As stated before, the only part of the system that is working differently is where the air passed through the evaporator is coming from.

I agree with you that over time the recirc air should be cooler than the outside air because the system has had time to cool it. But the comment I made was regarding Michael’s post which states “ In order to reduce the A/C power consumption…..Recirc air mode is on when the engine is started…" not after running for several minutes.

The system defaults to this setting as a fuel saving tactic assuming 1) you will actually be driving for some time after starting the vehicle and 2) humans will not remember to turn it to recirc for fuel savings. It's easier/cheaper for the system to have a on/off logic mechanism (>75F=recirc on) than some algorithm that determines when it's the best time to turn it to recirc.

With regard to when the car is first started, whether the A/C is in recirc mode or not, the temperature is set to the coldest setting. So the question to me is whether there is any difference to the cooling system, other than the air source.

There is no difference other than the air management (inside air vs. from outside)

It seems to me the cooling temperature within the coils is the same regardless of the recirc switch, so there shouldn’t be any difference to the power consumption of that portion of the system.

The compressor is either running (more work=more fuel) or not running (less work=less fuel). By setting itself to recirc it will save fuel during the drive once the cabin air has been cooled as the compressor will have less work to do. That is the whole goal of this feature and why this logic condition/setting is determined at startup.

And, if 00Sebby is right that the fan is just louder and not working any more, that just reinforces my point that the system isn’t working any harder or consuming anymore energy.

I am. This point is valid for the initial startup time. At this moment, it doesn't matter which mode it is in. Again, it sets it for the expected drive to follow.

Beyond the issue of whether the system is working harder, I have found overall the cooling system of these cars is marginal and find that it works best when running at highway speeds with recirc off. That’s just my opinion, but it seems to be true in my car. Even at city speeds, the system seems to cool better though the difference is less obvious. Therefore, the first thing I do when I start the car in the summer is hit the recirc button. I would be much happier if the setting were to remain on or off from the last use rather than having to change it on startup every time.

On mine, I find when I feel really cold, I look down and see that the recirc is on from when it was started. I like fresh air and not freezing so I turn it off for the rest of the drive. So at least on both of my 4Runners, the cooling is much more efficient with the recirc on.

 

[Michael-Dallas]

First, when the car is sitting in the summer sun, the air in the car is hotter than the air outside. So when you first start the car the recirc air going through the cooling system is warmer. By your logic it would be better to begin the system by pulling in the cooler air from outside. But even if the air outside is warmer I don’t see the energy to run the system being increased by starting with the recirc on. What part of the system is working differently?

If I am parked in a parking lot out in the sun, then I will crack the windows, and when I return, I will open the doors for a minute to let the interior air temp equalize to ambient air. Where I'm at, we get triple digit temperatures 2-3 mos during summer.

00Sebby answered your other questions, so I'll leave it at that. If you understand how AC (and automotive AC) works, then that may help. If this was a BMW, then it would have an auto recirc setting, but this is a Toyota - it's not that intelligent. Even my wife's Honda Passport w/ auto climate control starts in recirc mode in the summer.

 

[ElectroBoy]

Maybe it depends on your trim and model year. On my 18 ORP if you leave the temperature knob in the Max AC setting when you turn off the engine then yeah, when you start the car next time it will come up in recirculate mode. That’s by design. All that the Max AC setting does vs the lowest temp setting is shut the recirc door. I never use that Max mode since I want to control the recirc feature manually. Another feature is that the two diverter modes that blow air to the windshield to defrost will turn recirc off. And you cannot turn recirc on until you click off one of those the windshield modes.

Do you leave AC on and in Max AC all the time, and turn the car off that way?

 

[00Sebby]

Maybe it depends on your trim and model year. On my 18 ORP if you leave the temperature knob in the Max AC setting when you turn off the engine then yeah, when you start the car next time it will come up in recirculate mode. That’s by design. All that the Max AC setting does vs the lowest temp setting is shut the recirc door. I never use that Max mode since I want to control the recirc feature manually. Another feature is that the two diverter modes that blow air to the windshield to defrost will turn recirc off. And you cannot turn recirc on until you click off one of those the windshield modes.

Do you leave AC on and in Max AC all the time, and turn the car off that way?

20 ORP it will default to recirc at the lowest max setting all the time and at the cold setting one click up when it is hot outside. My '10 TE would only default to recirc in the max setting but never default to recirc on the cold or higher settings.

 

[rc10mike]

I have a 17 ORP and I usually leave it 3 clicks above MAX. It always starts in recirc mode. Weird.

 

[DAW89446]

My ‘18 SR5 is default recirc on. That said, I wish it wasn’t. Being an old fart, I tend to dislike the trend that vehicles think for me. I kind of like to think for myself. I’ve done just fine this way for five decades of driving.

My 4Runner doesn’t have the luxury of a garage. Though it isn’t particularly hot where I live (record high 109º), the car is hot inside. Recirculating hot air means slower cool down time. I also keep my windows up, as otherwise the interior gets all dusty. I’m not as picky as to how the outside looks, but I get picky about seeing a coating of dust on all the black surfaces every time I enter. So with the windows up and the truck sitting in the sun, it’s pretty toasty in there. And with the AC in normal mode, the fan noise is lessened as well.

Yes, it’s minor, but it is irritating that I have to hit the recirc button to off every time I start up. This is my first vehicle with a default recirc on system and I still prefer to have personal preference things set as they were the last time I drove it.

 

[Drobs]

I like recirculation for keeping out the smell of dead skunks. Also works decently for keeping out the smell of smoke as well.

 

[Pirateghost]

Ignorance is a bliss. Ride a motorcycle with a white bandana and report back. Riding on my bike not only can you smell the exhaust but it also leaves a nice outline of black junk on the bandana. So I never ride with windows down in the city or on highways. On country roads it's a different story.

People have no idea of the amount of micro rubber particles are on modern roads. I towed a car behind my rv. When starting the car after towing for a day, you can smell the odor of burning rubber. It is all accumulated from road debris.

 

[Drcoffee]

Recirculation is better then breathing all the exhaust out there..

Where do you live? China

My ‘07 turns on recirculate even if the AC is off. 90*F day, no AC and the system thinks its a good idea to recirculate 100*F interior air. Go figure.

Is there a way to defeat this with tech stream?

 

[1jzgte]

The compressor is either running (more work=more fuel) or not running (less work=less fuel). By setting itself to recirc it will save fuel during the drive once the cabin air has been cooled as the compressor will have less work to do. That is the whole goal of this feature and why this logic condition/setting is determined at startup.

can anyone verify if this cycle off/on applies to non-limited auto climate systems? I have an SR5 with the standard a/c knob system. Will the compressor automatically cycle off and on as well?

 

[spartacus]

Where do you live? China

My ‘07 turns on recirculate even if the AC is off. 90*F day, no AC and the system thinks its a good idea to recirculate 100*F interior air. Go figure.

Is there a way to defeat this with tech stream?

Just stick your head out the window while driving.
Read my quote about riding a motor bike with a white bandana.
The only way to defeat it is move the dial up one notch so it's not on AC and then press the direct air symbol button.

 

[Drcoffee]

Just stick your head out the window while driving.
Read my quote about riding a motor bike with a white bandana.
The only way to defeat it is move the dial up one notch so it's not on AC and then press the direct air symbol button.

My Sport has the three knobs and a push button AC. I have it set to vent & feet, with AC off, temp 67*F. It still defaults to recirculate when I start up the truck. I guess it would make sense if the AC was on, but it isnt.

 

[spartacus]

My Sport has the three knobs and a push button AC. I have it set to vent & feet, with AC off, temp 67*F. It still defaults to recirculate when I start up the truck. I guess it would make sense if the AC was on, but it isnt.

I'll have to check on my 5th Gen. Normally I take a few seconds to setup to how I want it at startup. I can understand the frustration when you have to do it at every startup.

 

[2021nightshade4x4]

When AC runs w/ recirc off, it brings outside air for the AC system to cool. Recirc closes the flap that brings in outside air. So it takes less effort to keep air that's already been cooled, cool, than to cool outside hot air.

Finally, someone who “gets it”. Thank you.

Also the only reason the A/C in your home can get the temp below 80 on a 100 degree day... recirculation.

Let’s not forget a big one - humidity. Turn off recirculate in the south and your hair will start to frizz.


Sent from my iPhone using Tapatalk

 

[N6WRV]

Recirculation is better then breathing all the exhaust out there..

Like the rotten exhaust stench from diesels?

 

[cbaty08]

The Car Care Nut (Toyota tech on YT) will tell you.. only use recycled air WHEN YOU HAVE TO..

And, when you do, be sure to run FRESH AIR for 15 minutes for every HOUR of RECYCLED air - to ensure the condenser dries out and doesn't stay filled with moisture.. and end up smelling like shitte.

And, no, my 2021 Pro doesn't default to recycled air.

 

[spartacus]

The Car Care Nut (Toyota tech on YT) will tell you.. only use recycled air WHEN YOU HAVE TO..

And, when you do, be sure to run FRESH AIR for 15 minutes for every HOUR of RECYCLED air - to ensure the condenser dries out and doesn't stay filled with moisture.. and end up smelling like shitte.

And, no, my 2021 Pro doesn't default to recycled air.

The condenser gets pretty dry when you are driving turning the recirculation on 5 minutes before you stop will take care of'the musty smell in humid climates. Fourtunately for me it's pretty dry up here.