Better for air conditioner unit: recycled air or outside air?

nissan
sentra
fans
airconditioning

#1

Is it better to use recyled air or outside air with the A/C unit? I always set my fan to “recyled air” to get better gas milegae, but my coworker says using fresh air is better for your car–doesn’t damage the compressor. ??


#2

Your car doesn’t care. I use recirculate on hot and humid days. Neither setting is potentially damaging.

It should however be turned off when using your defogger function, and in the winter in general.

I didn’t know you got better gas mileage with recirculate.


#3

The compressor doesn’t care whether you use fresh air or recirculated air, so set the controls any way you want. It makes no difference to the mechanical things, nor will it have any impact on fuel mileage.

I’d really love to hear your co-worker’s explanation of how recirculated air damages the compressor. Could you get him or her to post it?

While you’re at it, can you explain how recirculating air increases gas mileage?


#4

Theoretically only, the recycled air is both cooler and has less moisture in it. The cycle is designed for quick cool-down when you start up the car. However, car manufacturers HAVE to tell you that it’s not healthy to recirculate the same air over and over. You need fresh air; so the recycle is only recommended to start the cooling process.

On some cars the continued use of the recycle mode can ice up the condenser, resulting in no air flow.


#5

I always set my fan to “recyled air” to get better gas mileage

You will get better mileage. My magic calculator says about 24 feet per gallon. Frankly almost nothing. Back in the old days when A/C was the exception not the norm, it would make a noticeable dent in the mileage. On today’s cars, it is really not worth the worry.

That Fresh air is better for your car, is another old story from prehistoric days.

[b]  Use the settings to keep you comfortable and safe.  Use the air and heat to keep your glass fog free. [/b]

#6

Good to know–thanks!


#7

I can attest to keeping the recirc option on during the winter. Instead of scraping the outside of the windshield, I had to scrape the INSIDE of it.


#8

The only thing recycling the air does is draw air from the cabin instead of outside. If it’s winter and you want to warm your car quicker it will draw the cool air from the cabin and give you back warm air. If you don’t recycle then the warm air is just mixing with the cool air and it could take a while longer to warm up. Same goes for air conditioning. So it could be useful in quickly changing the cabin temperature.
Another reason for using recycled air is if you are driving through a bad area where air quality is low, then you can keep out the bad stuff

General use won’t hurt anything it won’t save you any gas mileage and if anything your fans will be working harder to suction the air from inside than from outside when it is being blown against the car. I can imagine some complications could arise if strictly used all the time and for long periods. It won’t As one said the compressor could ice over since it is cooling already cool air, and you wouldn’t be getting fresh air. I would just use it as needed/wanted but not all the time. My mom keeps the windows up 24/7 and always has the air on recirculate. I always feel claustrophobic and like I’m suffocating when I get in her car.


#9

The “fresh air” option doesn’t just draw air from outside. I believe it is typically about 30% fresh air and 70% recirculated. Regardless, use of recirculated air in the winter (in cold climates) leads to excessive fogging of the interior windows and icing of the condenser. The recirculated air option is intended for use early in the cooling cycle (in the summer) for maximum cooling. In the winter it is completely unnecessary unless the outside temperature is so cold that even 30% outside air in the mix makes the heat too cool. It’s also good in car washes so you don’t have to smell all the chemicals.


#10

I think it is better to use the recirculate setting to cool the vehicle down faster.


#11

Actually, @bloody_knuckles, with the 3 Toyota’s and a Ford that I’ve owned and worked on, the fresh air cycle pulls 100% of the air from outside. All these vehicles have a flapper door that directs the intake for the fan, and it is either 100% recycle or 100% fresh. The only one that can do a mix was my old Toyota pickup with a manual lever that I could slide across halfway for a 50-50 mix. The others are all automatic controls, so the flapper is either one way or the other.