Temperature control and the recycling button...

[SocialStealth]

the manual for my car says the air recycle button should be OFF during most driving conditions. By off I mean open to the outside air.

Why is this? Is there any problem with it being on?


Theory:

If its humid outside, and I turn the A/C on, and have recycle OFF, I'm cooling down, but letting all the humid air from the outside in my car. Right?

With the same conditions, but with the recycle button ON, it will become less humid in the car, right? So eventually I could shut the A/C off and maintain a cooler temperature as opposed to if the recycle button was off, Right?

While we're on the subject, is there any way to insulate the car? I've heard that pink stuff is a bad idea for cars... Any ideas?

 

[Matt V]

The recycling button simply doesn't vent outside air into the car, just like if the switch is on the green side, then it's circulating (or recycling) while it's on the red side. You should keep the circulating button on at all times if you're using the A/C. Whenever I'm not using the A/C, I just keep it on vent and have the windows rolled down.

 

[thecrash91]

i found that when its open (taking in air from outside) and the fan is off air still comes through the vents, so i usually turn it to circulate when the cabin is already comfortable so new air doesnt come in and the fans are off. is this bad?

 

[SocialStealth]

i found that when its open (taking in air from outside) and the fan is off air still comes through the vents, so i usually turn it to circulate when the cabin is already comfortable so new air doesnt come in and the fans are off. is this bad?

I'm not sure. I was reading the manual and it said to keep the button on green for daily driving.


I'm a bit confused matt, are you saying the button should always be on red when the AC is on?

 

[Matt V]

Yes, keep the unit on circulate when the A/C is on. If you switch it while it's on you'll notice that you get more air flow when you're sitting and put it on circulate. This happens because the vents aren't open and warm air (or cold air) isn't getting in.

 

[dmention7]

It's generally suggested to leave recirculation off unless you're trying to heat up or cool down the cabin quickly. With recirculation off, you keep the freshest air possible in the cabin, and avoid (the admittedly minute) possibility of exhaust fumes or whatnot from accumulating.

Once the cabin is at a comfortable temp, a properly-functioning climate control system will usually have no trouble maintaining the temp, so there's no point in leaving it on recirculate longer than necessary.

I always have the fan set by default to the lowest speed whenever I'm driving, whatever the weather. Seems like every car I've ever driven in gets a bit stuffy or stale without that little bit of constant airflow.

 

[hornsfan10609]

I keep the recirc off most of the time, the car can get uncomfortable without that fresh air coming in.

 

[ShortBusDriver]

Theory:

If its humid outside, and I turn the A/C on, and have recycle OFF, I'm cooling down, but letting all the humid air from the outside in my car. Right?

With the same conditions, but with the recycle button ON, it will become less humid in the car, right? So eventually I could shut the A/C off and maintain a cooler temperature as opposed to if the recycle button was off, Right?

Air conditioning dehumidifies the air. Ever notice after you park on a humid day while running the A/C it will drip water all over the ground under the car? This is the water the A/C is removing from the air. Try it sometime: on a really humid day, blast the vents with the A/C off with 'recycle' on green. Smell the air, it will feel and smell really humid, then turn the A/C on. After like 20 seconds you will notice it smells different and feels much less humid (as well as being cooler).

This is because as the air flows over the cold coils of the A/C the water in the air condenses into liquid and drips onto the ground.

It's not bad to have it on recirculate if you want, but its just usually better to have some fresh airflow.

 

[slavrenz]

Air conditioning dehumidifies the air. Ever notice after you park on a humid day while running the A/C it will drip water all over the ground under the car? This is the water the A/C is removing from the air. Try it sometime: on a really humid day, blast the vents with the A/C off with 'recycle' on green. Smell the air, it will feel and smell really humid, then turn the A/C on. After like 20 seconds you will notice it smells different and feels much less humid (as well as being cooler).

This is because as the air flows over the cold coils of the A/C the water in the air condenses into liquid and drips onto the ground.

It's not bad to have it on recirculate if you want, but its just usually better to have some fresh airflow.

Agreed. Contrary to what it may seem, recirculated air will actually be more humid than outside air. It is a combination of air not passing over the condenser and moisture released from people inside the car, which builds up very quickly.

 

[Wagonbacker9]

Agreed. Contrary to what it may seem, recirculated air will actually be more humid than outside air. It is a combination of air not passing over the condenser and moisture released from people inside the car, which builds up very quickly.

false. and air CONDITIONER actually dehumidifes the air BEFORE cooling it. so if you are pulling in 100*, VERY humid air... the AC will likely not get it very cool at all... once the humidity is out of the air, THEN it will start to cool it.

 

[SocialStealth]

My A/C blows nice and cold, but I noticed that without the A/C on, the car begins to build humidity rather quickly.

Would insulating the doors help prevent this and allow me to intermittently use my A/C (rather than having to keep it on all the time)

 

[Wagonbacker9]

depends on the outside air... but insulating the doors will do nothing to change humidity.

 

[SocialStealth]

depends on the outside air... but insulating the doors will do nothing to change humidity.

would it prevent the car from heating up so much in the summer?

or is that an issue with the windows

 

[Wagonbacker9]

heat will always creep in anywhere it can... I would say insulating the doors is likely a complete waste of weight, time, and energy, you'll see some gain I'm sure... but I just don't see it as worth it.

 

[ucMP3]

First off, there is already insulation all around the car from the factory. But, I don't think adding insulation to only the doors will make any difference. Even adding extra insulation to the entire car would likely yield very minimal differences in retaining heat/cold. You can always be the one to guinea pig the idea tho. If it works maybe others will follow

As for me, I always have the windows down for A/C unless its raining. With the vents open blowing on my feet of course

 

[SocialStealth]

err well... I feel like an idiot asking this but...

I just got 36 MPG on my last fill up (I actually drove about 200 miles on a tire with a hole in it without noticing...when I found it it had 6 lbs of pressure)

So I'm eager to see my MPG on properly inflated tires

I've been driving without any A/C to try to get the best MPG I could.

errr.... I dont like rolling down the windows because I'm afraid it'll cause drag and ruin the aerodynamics of the car (stoned)

How much MPG does rolling down windows cost you?
How much MPG does the A/C cost you?

 

[bucksatan]

^Depends on the speed you are going.

 

[Wagonbacker9]

err well... I feel like an idiot asking this but...

I just got 36 MPG on my last fill up (I actually drove about 200 miles on a tire with a hole in it without noticing...when I found it it had 6 lbs of pressure)

So I'm eager to see my MPG on properly inflated tires

I've been driving without any A/C to try to get the best MPG I could.

errr.... I dont like rolling down the windows because I'm afraid it'll cause drag and ruin the aerodynamics of the car (stoned)

How much MPG does rolling down windows cost you?
How much MPG does the A/C cost you?

you care too much.... i'd rather drive comfortably. lol

 

[slavrenz]

false. and air CONDITIONER actually dehumidifes the air BEFORE cooling it. so if you are pulling in 100*, VERY humid air... the AC will likely not get it very cool at all... once the humidity is out of the air, THEN it will start to cool it.

The evaporator coils are cold relative to the surrounding air, which causes humidity in the air to condense. Thus, if you are recirculating air that is naturally more humid from human perspiration, you are going to have a harder time cooling it.

I guess we can agree to disagree, and I appreciate any corrections to my explanations, but there's no need to add a pretentious "false" first.

 

[Wagonbacker9]

The evaporator coils are cold relative to the surrounding air, which causes humidity in the air to condense. Thus, if you are recirculating air that is naturally more humid from human perspiration, you are going to have a harder time cooling it.

I guess we can agree to disagree, and I appreciate any corrections to my explanations, but there's no need to add a pretentious "false" first.

the ambient air would have to be VERY dry to be dryer than the air recirculated from inside the car. your point is valid, but only under VERY certain circumstances.