My wife has a 2007 Chrysler Town & Country. We’ve been using the AC a lot lately due to extreme heat. Her owner’s manual says only to use the AC recirculator sparingly–at start up and in extreme heat but then to turn on the outside vents. It seems to me that the recirculator helps your AC run more efficiently and saves you fuel. Why does the manual say this?
Congratulations on reading your owner’s manual. Many people do not do that, then come here asking questions that could be answered by their owner’s manual. The reason Chrysler recommends this probably has to do with getting fresh air into the vehicle. Recirculate can help cool the car down faster, but once you are comfortable you should move on to pulling in outside air. The a/c system will not run any less efficiently either way. It will still cycle as needed to maintain line pressure, and using recirculate will certainly not save fuel. Not using the air conditioning at all will save fuel, but to me the comfort is worth the tiny loss in fuel economy.
The AC may not run less efficiently, but it will keep the car cooler in extreme heat and humidity. Around here, you start with the outside air because it is only around 100, where the inside air can be 130 or higher. Then as the vehicle cools down, you switch to recirculate.
The recirculater cools the air in the vehicle while the vents cool the hot 100 degree outside air, thus the recirculater does a better job. However it does not run more effeciently, the compressor is working just as hard. Now there are a lot of guys on here smarter than I (or they think they are) I don’t think there would be a problem with running the recirculater most of the time, unless the vehicle was fogging up, then you might need to run an outside vent. BTW I have an '09 Grand Caravan, how do you like the Chrysler??
plus- If run long and hard enough the system could freeze up without the input of outside air.
and - the habit of running recirc usually means you’ll leave it like that when parked…sealed up tight as a drum with no air exchange whatever.
It’s those people who will be posting here about inside air temp too hot after being parked…windows popping/breaking from heat pressure build up…then in the winter, frost on the inside.
Let me point out one more thing, the designers all work up north and they don’t know squat about life here in the south. They might be getting a taste of it this year because of the high humidity due to last winters high snow pack and the current heat bubble.
Normally they are seeing 90-100° with relatively low humidity. The outside air has less humidity than the air inside the cabin. Inside the cabin, respiration and perspiration increase the humidity. The evaporator has to handle all this excess humidity in the form of condensation.
Down here in the south where we deal with 95-105° and 80-99% humidity, the air in the cabin will be not only cooler after a few minutes, but less humid, in-spite of our respiration and perspiration as the AC has wrung out a lot of the moisture already.
I think some of those designers ought to spend a summer down here and experience a summer rain in the south. Then maybe they would add another position to the HVAC, dash vent and defrost (defog). It can be difficult to get comfortable in a summer rain when you need to run the defog and the only choices are full defog and defog/floor.
“plus- If run long and hard enough the system could freeze up without the input of outside air.”
Not true if the AC is working properly
“and - the habit of running recirc usually means you’ll leave it like that when parked…sealed up tight as a drum with no air exchange whatever.
It’s those people who will be posting here about inside air temp too hot after being parked…windows popping/breaking from heat pressure build up…then in the winter, frost on the inside.”
Also not true, even in recirc, the vehicle is not air tight.
But system freeze up IS one of the reasons they say that, albeit rare.
Interior frost IS another reason they state that instruction.
Running in recirculate all the time shouldn’t hurt anything unless there’s something specific about Chrysler a/c that will be damaged. I run the a/c on all my Fords and my wife’s Chevy on recirculate all the time.
When I park on a really hot day I usually crack the windows a little.
Many add-on air conditioning units in the late 1950s through the 1960s (the Mitchell Mark IV was one example) just recirculated inside air. The evaporator and fan were in a box that hung down under the dashboard. I don’t remember anybody suffocating using one for lack of oxygen. My dad had such a unit in a 1963 Buick LeSabre. It could get the interior of the car so cold that the the cabin could be used as a meat cooler.
ken green, I don’t disagree with you on the inside frost issue in the winter, but right now, frost is not an issue.
This has nothing to do with question at hand, but do you remember when the A/C unit was in the trunk? Like on GM cars in the 50s?
No but I do remember when the car phone was in the trunk, and it took up most of that. The handset was on the dash and it looked just like a POT (Plane Old Telephone).
I certainly do. GM had these units available in the 1953 Oldsmobiles, Buick Super and Roadmaster models and the Cadillacs. The evaporator and fans were in the trunk. Air was ducted through transparent tubes along the right and left hand side of the roof of the vehicles. The air conditioning system was completely separate from the heating system. At Nash (later American Motors), an engineer by the name of Nils Erik Wahlberg patented a system that integrated the heater with the air conditioning and everything was behind the dashboard or under the hood. By the late 1950s, all manufacturers had gone to this arrangement.
“At Nash (later American Motors), an engineer by the name of Nils Erik Wahlberg patented a system that integrated the heater with the air conditioning and everything was behind the dashboard or under the hood.”
Nash’s famous Weather Eye system!
That integrated HVAC system was vastly superior to all of the other heating and A/C systems on the market at the time.
keith
no, frost isn’t the issue right now,
BUT breaking a developing habbit is.
the owner’s manual says that for a reason and those are some of the reasons, albeit stemming from the legalese disclaimers you see on many products, it happed to someone sometime who claimed it the manufacturers fault. Now they have to warn everyone " do not eat" , “do not use in bath or shower” .
The first automotive A/C system was installed on a few Packards, back in the late '40s.
There was one fan speed, no on/off switch, and no temperature control. In other words, it was on all the time under the proper conditions (see below for more details).
At low speeds, the effectiveness of the A/C was so minimal that it was barely perceptible.
But, when driven at high speed, the cabin of those few air-conditioned Packards could have been used to store meat!
Since the only A/C vent was on the rear package shelf, the rear seat passengers sometimes complained about the absolutely frigid air directed at the back of their necks during highway drives.
Clearly, this first system had many faults, including the requirement that the belt driving the A/C compressor had to be removed once the summer was over. Because there was no on/off switch, the system operated continuously unless the drive belt was removed.
For most vehicles, the recommendation I’ve always seen, heard, and used myself is to start off (in very hot weather) with the windows open, for the first 5 minutes or so. This gives the inside of the car the chance to at least get down to outside temps. once that is done, roll the windows up, recirculate on, until you reach a decent temp, then recirculate off.
(I’ve said before, and I’ll say again I’m not an A/C guy, but…) The hardest job for an A/C system to do is cool a very hot car when first started with the recirculate on.
Turning off recirculate also helps keep other smells from building that you don’t want. Like smoke, outside odors (skunks, local mills, exhaust, etc), whatever. Turning it on when entering things like smoke clouds, areas you know have smells associated with them can keep those smells out of your car, then when you’re past them, crack a windows and turn recirculate off.
Anyway, use it or ignore it. That’s just my .02, and it seems to work for our vehicles.
Chase
Just drive it like you want to. It is not a matter of life or death! Nor will it damage anything.