Climate Control additional settings

[Bassik]

Hey I've had an issue with my climate control for a while now and being that it's in winter now I keeping having to turn the induction recycle button to on manually.

So every time I start the car it defaults to off which means within 5 mins my windows start to fog up. I don't want to have the A/C on and I don't want the heater on. This is a major pain in the butt because it just seems all the buttons work together, like you can't have the A/C off with recycle on and vica versa. Why is this and is there a way to change the default settings with coding?

I wish I went for the standard A/C now.

[vdubmotorworx]

They are all like this...defaults to recirc off when ignition is cycled ..never heard of a VCDS coding change for this one...VDUB..

[pologti18t]

Probably a safety reason for the recirc to disable on a car restart. It's not good to drive around with recirc on for long periods.

Don't windows fog up faster if you have recirc and no A/C on?

[nomadx38]

This is implemented as a safety feature (and is noted in the car manual).

It turns off the recycled air 20mins after the ignition is turned off. It is designed like this so that when the car is turned back in fresh air is pumped back into the car, clearing out the oxygen deprived stale air. Stale air can cause a lack of concentration and tiredness.

Compleatly normal and is for your safety. As far as I know its hard wired and is not a software thing.

[gavs]

Climate Control additional settings

Don't windows fog up faster if you have recirc and no A/C on?

Yeah, my thoughts exactly.....

[Bassik]

Probably a safety reason for the recirc to disable on a car restart. It's not good to drive around with recirc on for long periods.

Don't windows fog up faster if you have recirc and no A/C on?

No they don't because the air from outside is usually colder in winter then it is inside then it starts to fog up immediately. I do it every morning... as I drive out my driveway and hit the highway (3mins) I have to flip the recirc switch on and within mins the windows clear up again, without putting on an A/C or fan etc.

Ok well if it's a safety thing then I guess it will be on all cars. Suppose I'll just get used to it.

I'm used to older cars where you press the button and it stays on until switched off haha.

[LunchboxVRS]

Pologti18t & Gavs right.

The windows fog up due to the difference in temp between cabin and outside. As soon as you step in and start breathing warm air out the temp tries to equalize and your warm breath and body heat rushes to the windows which are the same temp as the outside temp. This rapid change causes the moisture. Buy putting the a/c on you reduce the temp allowing the the temp the equalize slower and. A more even rate stoping that sudden change and moisture forming. The a/c also draws moisture out of the air which helps stops the "fog" (moisture).

[alexaescht]

Pologti18t & Gavs right.

The windows fog up due to the difference in temp between cabin and outside. As soon as you step in and start breathing warm air out the temp tries to equalize and your warm breath and body heat rushes to the windows which are the same temp as the outside temp. This rapid change causes the moisture. Buy putting the a/c on you reduce the temp allowing the the temp the equalize slower and. A more even rate stoping that sudden change and moisture forming. The a/c also draws moisture out of the air which helps stops the "fog" (moisture).

It's more moisture related than temperature related but both play a role in fogging up windows.
The cold windows provide the perfect place for the moisture in the air to condense (and so fog up) but as long as you have the ac switched on, you can have the temperature set to 26 C and the windows will remain fog free because the moisture in the air condenses on the ac condenser and not on the windows (yes, even when the heating is on the air is first cooled and dehumidified by the ac and then heated again by the heat exchanger in the engine bay)
Also, heat is good at removing fog from windows. That's why so many cars sold in cold climates have large capacity electric heaters for the windscreen de–mister (my Megane for example has a 1,000 watt electric heater for that purpose) allowing the air in the cabin to get warm while the engine is still cold.

Alex.

[LunchboxVRS]

It's more moisture related than temperature related.

Alex.

No. You can have a little to a lot of moisture in and out of the car and it won't fog. As soon as you change the temp in side relative to outside with out removing the moisture it will fog as it trys to reach a equilibrium (Second law of thermodynamics: Heat cannot spontaneously flow from a colder location to a hotter location) you can use heat to remove the moisture but it will take longer or you need a lot of heat quick. Recycling the air with heat as the op is trying to do will work but it takes minutes compared to seconds with the air con.

[alexaescht]

No. You can have a little to a lot of moisture in and out of the car and it won't fog. As soon as you change the temp in side relative to outside with out removing the moisture it will fog as it trys to reach a equilibrium (Second law of thermodynamics: Heat cannot spontaneously flow from a colder location to a hotter location) you can use heat to remove the moisture but it will take longer or you need a lot of heat quick. Recycling the air with heat as the op is trying to do will work but it takes minutes compared to seconds with the air con.

Which is why I said "but both play a role in fogging up windows."

Recycling the air will just continue to increase the humidity of the car and worsen the problem (in theory) because of the moisture we breathe out and sweat etc. building up in the cabin.

[LunchboxVRS]

Yea but you said its more moisture but its the temp in this case.

[alexaescht]

Yea but you said its more moisture but its the temp in this case.

Ok well maybe that last piece of writing wasn't my best. Humans make mistakes after all.
But really both moisture and temperature contribute to foggy windows – if it was only temperature (as you appear to think) then if there was no humidity in the car the windows would still fog up (which is incorrect, as the moisture needs to come from somewhere and no, heat flow doesn't magically create moisture.)

Anyway, why don't people just turn the ac on and set a temperature? That will solve all of your foggy problems. It's not like the ac even zaps that much power, or uses that much fuel and seeming its part of your car, why not use it?

[Barracuda]

Ok well maybe that last piece of writing wasn't my best. Humans make mistakes after all.

Anyway, why don't people just turn the ac on and set a temperature? That will solve all of your foggy problems. It's not like the ac even zaps that much power, or uses that much fuel and seeming its part of your car, why not use it?

Exactly! During winter I have the climate control set on 23 degrees with the fan speed at 1 or 2 and my windscreen never fogs up. But as soon as I turn it off, the windscreen will start to fog-up.

I haven't noticed a single change in my fuel economy since I've started to have the air conditioning on every day...

[LunchboxVRS]

Ok well maybe that last piece of writing wasn't my best. Humans make mistakes after all.
But really both moisture and temperature contribute to foggy windows – if it was only temperature (as you appear to think) then if there was no humidity in the car the windows would still fog up (which is incorrect, as the moisture needs to come from somewhere and no, heat flow doesn't magically create moisture.)

Anyway, why don't people just turn the ac on and set a temperature? That will solve all of your foggy problems. It's not like the ac even zaps that much power, or uses that much fuel and seeming its part of your car, why not use it?

I never said you don't need moisture. I just stated temp was the deciding factor in fogging. How you get rid of it (whether you use A/C or not) is up to the individual. But without the temp Change. moisture is just going to free float in the air.

[Bassik]

oh wow ok...

See I always thought it was just because the recirc button switched off just means it's letting the air from outside inside the car and with the demisters on the air drives straight to the front window. Normally if I have it set to face or feet it doesnt happen, but I don't like heat on my face so I just leave it on feet and front window.

I know A/C will clean everything up quicker I'm just comfortable with the temps in the morning and don't want either on. Also another thing is you can have the A/C on without having the recirc on. I found this annoying as well.

Guess it's just something most cars have these days.