Which is better for AC Recirculate or outside air?

[roperteacher]

In response to one of the replys I got on my other thread... Which is a better setting for our AC systems?? TO put the dial on RECIRCULATE or the one up from that where it uses outside air??? Would either of these cause more icing up of the system?? I have always used Recirc as I thought it made the AC unit work less?? Just curious! Thanks!:-laf

 

[ttbird]

Recirc setting will produce a colder interior causes it's cooling cooler air.

 

[BHolm]

In the "old days" re-circ was the "MAX" setting on the AC system. What it does is recirculate interior air rather than draw fresh air. I personally would prefer the freshest air possible. Truely its best use is ina tunnel, wher ethe air is stale, or when passing through northern Indiana where it often just plain stinks (no offense to residents).



The way I use it is as a quick cool down then back to using outside air. The other method is to roll the windows down until the hot air escapse and then use the outside air for AC.



The funniest use of re-circ is in little Jap cars where in winter they fog all the windows by leaving the re-circ on. I think it is pretty much best to use fresh air unless there is a good reason not to.

 

[Highfinance97]

In the "old days" re-circ was the "MAX" setting on the AC system.

2nd gen 24valves??? is that what you mean??



my 2nd gen 12Valve has re-circ,but my 24Valve only has "MAX"



Michael

 

[roperteacher]

I was kind of thinking that Recirc made the system work less to keep the air cold because it was the same air! BUt I like the idea of using ouside air! I am going to use the outside setting tomorrow and see if it makes a difference on weather the condensor water drips fromn the front of the engine any less!! But I am glad to hear it;s normal... For once!!! LOL Oo.

 

[makelemen]

Remindes me of the time passing road kill and the dog was sniffing the vent while the fresh air was on.

 

[Gary - K7GLD]

We personally use the "Max" - recirculating mode. We bathe regularly, and don't have smelly passengers, smokers or similar "stinky" stuff in our cab :-laf, the A/C probably is more efficient on that setting, and my wife's allergies are less bothered when we're not sucking in outside air - pretty much the same as our home A/C setup...

 

[jgillott]

I'm not sure if it is an indication of the AC system working harder on the outside air settings, but I notice the compressor on my '07 cycling considerably more in the recirculate mode than on normal.

 

[Gary - K7GLD]

I'm not sure if it is an indication of the AC system working harder on the outside air settings, but I notice the compressor on my '07 cycling considerably more in the recirculate mode than on normal.

YUP - the compressor has to run less, and for shorter periods of time when it's not having to cool that warmer outside air - should also have a slight effect on fuel consumption!



When it's cooling that warmer outside air, the A/C compressor undoubtedly runs for longer periods of time, and shuts down less...

 

[jgillott]

- should also have a slight effect on fuel consumption!

This truck could use all the help it could get in that department.

 

[Matt400]

From a service standpoint. . fresh air is best and contributes to less chance of mold in the air box. On our personal vehicles we switch to recirc only when outside air is unwanted like when you see a dead skunk on the road.

 

[Grizzly]

From a service standpoint. . fresh air is best and contributes to less chance of mold in the air box. On our personal vehicles we switch to recirc only when outside air is unwanted like when you see a dead skunk on the road.

I agree with Matt400 on this. I sometimes use recirculate for a quick cool down then switch to outside air.

 

[Hoefler]

You will find that you will get the interior cooler on recirculate. Use the fresh air to purge the hot air from the vehicle when you first get in when it has been setting out in the sun. After about 3-5 minutes, switch to recirculate. The A/C will work less in this mode for 2 reasons: 1 the air is less humid, 2 it is already cooler than the outside air thus making your system work less to get you to a comfortable temp. You are less likely to freeze up in recirculation mode than fresh for the above reason, also less air born pollutants to cause the mold and mildew to stink it up. Just think about the system in your house, it is always in recirculating mode, never fresh.

 

[DPKetchum]

Recirculate is really ONLY to get the vehicle cool and then fresh is suppose to be used. to maintain it. If left on RECIR long enough they ALL will get the STINK. Just depends on who's nose is use to it.

 

[Grizzly]

You will find that you will get the interior cooler on recirculate. Use the fresh air to purge the hot air from the vehicle when you first get in when it has been setting out in the sun. After about 3-5 minutes, switch to recirculate. The A/C will work less in this mode for 2 reasons: 1 the air is less humid, 2 it is already cooler than the outside air thus making your system work less to get you to a comfortable temp. You are less likely to freeze up in recirculation mode than fresh for the above reason, also less air born pollutants to cause the mold and mildew to stink it up. Just think about the system in your house, it is always in recirculating mode, never fresh.

You and the Owner's Manual don't agree.

 

[DPKetchum]

Its the other way around.

 

[Bob4x4]

Another downside of keeping it on recirc is the air may be dehumidified too much... ... ... leaving your eyes too dry for comfort



Bob

 

[Badunit]

Its the other way around.

Most of what was said is true. Recirc air is less humid and it's cooler than outside air. I don't have my owners manual with me right now but I'll assume the part that's "the other way around" is about it freezing up. I would imagine that hot outside air blowing across the coils helps keep it from freezing up, even if it is more humid.



I personally like riding with the windows down, even on hot days. But that's just me. If it's too hot it'll be windows down and AC on in non-recirc mode. If my wife's with me it's AC on and maybe my window down (or maybe not). She likes recirc mode. I switch it off when she's not looking.



The one thing I've noticed about recirc mode has to do with the heater in the winter. My truck is inconsistent with heat so I often put it in recirc mode so I don't get bursts of cooler air (especially when stopped).

 

[JDerrick]

My dad asked this question to his fire department mechanic( whom also owned an automotive AC repair business on the side) some 15 years ago about his F250 with the 6. 9L corn binder. He was told that MAX is a good setting to use in stop and go traffic to help keep the air cooler and to help keep the exhaust fumes out of the passenger space. This higher setting also compensated for heat that could not be efficiently removed from the system in city traffic. NORM or outside air was a good setting to use on the highway when with the vehicle moving at highway speeds it had more air passing over the condenser in the front to help remove heat from the system. He stated that the NORM position when on the highway would also cause the compressor to not cycle as much. The down side is you are sucking all of the out side air into the passenger space... ... ... ... ... ... ... . makes sense to me I guess... Oo.

 

[betterthanstock]

No one brought up the point of people (and animals) using up oxygen. You'll pass out if you leave it on recirculate all the time (first you'll get a headache or nauseated feeling). House AC has by law a small percentage of fresh air brought in all the time (at least in some localities, and newer window AC units have a hole to let in fresh air). I suppose newer cars must have that too, or a lot of people would pass out and wreck (or maybe they do?). I have caught myself feeling drowsy after forgetting it on recirc for half an hour or so.