A/C on by default?

GBX · 11-04-2008, 12:10 PM

lately i've been noticing that when i press auto to turn on the air, it always turns the a/c button on, regarldess of whether it was pressed when i turned off the air. Its been in the 40's outside and i hit auto and the a/c light is on. What gives?

satakal · 11-04-2008, 12:24 PM

ac does more than cool air... it also pulls moisture out of the air. It's ok to have the snowflake and heat. I say, "no worries".

ibimmer954 · 11-04-2008, 12:27 PM

Yes, in cold weather the compressor will help prevent "fog" from forming on the windows by de-humdifying the air.

GreenThree · 11-04-2008, 01:12 PM

Quote:

Originally Posted by GBX

lately i've been noticing that when i press auto to turn on the air, it always turns the a/c button on, regarldess of whether it was pressed when i turned off the air. Its been in the 40's outside and i hit auto and the a/c light is on. What gives?

Same thing happens here. So there is no way to program so that the AC light does not automatically come on? Also, my center vent switch is to the right (Red for colder weather).

E92_328i_Boston · 11-04-2008, 01:14 PM

During my 14 years of driving I have never used the A/C in the winter (live in Boston) unless my purpose is to defrost or defog the windows. I know it removes moisture from the air, but 99% of the time all I need is simply the vents on warm, pointing to my feet. Easy pizzi. Why run the A/C compressor when you don't have to? There is no doubt that it puts more of a load on the engine, *all other things being equal*.

-A

Lassaxi · 11-04-2008, 01:33 PM

Quote:

Originally Posted by E92_328i_Boston

During my 14 years of driving I have never used the A/C in the winter (live in Boston) unless my purpose is to defrost or defog the windows. I know it removes moisture from the air, but 99% of the time all I need is simply the vents on warm, pointing to my feet. Easy pizzi. Why run the A/C compressor when you don't have to? There is no doubt that it puts more of a load on the engine, *all other things being equal*.

-A

Yup. Cold air is already very dry (in terms of absolute humidity). Cold air that's been heated up by your car's climate control system is even drier (in terms of relative humidity). I find it very uncomfortable to sit in a car in winter that is both heated and dehumidified because the air is simply too dry. Also, leaving the A/C on when not needed is one of the things that can contribute to the musty odor that some people notice coming from their climate control systems.

If your windows are fogged up in the winter, the fundamental problem is that the glass needs to warm up. Using the A/C can speed up defogging because it makes the air even drier than it already is. There's nothing wrong with that, but I think it's really just a waste of energy to leave the A/C on all the time in the winter.

E92_328i_Boston · 11-04-2008, 01:46 PM

Not to mention, dirty windows are much more apt to be fogged up (in my experience). Clean your windows inside and out, very well, and very often.

-A

Barmats · 11-04-2008, 01:51 PM

I keep my AC off unless I need to use it. So here in Minnesota, it's on most of the summer, but only on at other times if I need it to defrost the front window or if the humidity is high. In the winter I'll occasionally run it to defrost, but it feels like there's slightly less engine load when it's off.

bsd107 · 11-04-2008, 02:56 PM

I agree I HATE this "new" feature that the A/C comes on when you hit AUTO (on my E90 LCI).

The E39 5-series did NOT do this - the A/C button was completely independent of any other operation, and I greatly preferred this to the way other car companies linked it to AUTO (e.g. Honda, Lexus, VW, etc.).

I can't stand it that BMW copied this approach. I would have much preferred it if they had copied all other manufacturer's approach of allowing linking the driver and passenger side temps together so you don't have to move both temperature knobs every time you want to make a change....

Barmats · 11-04-2008, 03:18 PM

This is a slight deviation from the thread, but it would also be nice if there was a way to tie the 2 front temperature zones together so when you changed the driver's side temp, the passenger side changed as well.

I don't use the AUTO button very often and prefer to have manual control. But I agree - I don't like the way AC comes on automatically when you press AUTO.

satakal · 11-04-2008, 03:21 PM

3 things: First, notice how its the socal guys that say its no big deal?
Second, I don't understand where the passion comes from? Is it the LED being on, the loss of 1.73 hp, or is it the cost per tank of 20 cents? Third, what's winter?

I'm clearly missing something.

Lassaxi · 11-04-2008, 03:25 PM

Quote:

Originally Posted by satakal

3 things: First, notice how its the socal guys that say its no big deal?
Second, I don't understand where the passion comes from? Is it the LED being on, the loss of 1.73 hp, or is it the cost per tank of 20 cents? Third, what's winter?

I'm clearly missing something.

Yes, you're missing something. It's called winter.

tjnptel1 · 11-04-2008, 03:30 PM

it's not only our cars, all our family cars do this when you press the auto button.

3er BMW · 11-04-2008, 03:44 PM

You people should have ordered the manual a/c and not auto climate control.
You should run the compressor often for the seals not to dry out.

Lassaxi · 11-04-2008, 04:43 PM

Quote:

Originally Posted by 3er BMW

You people should have ordered the manual a/c and not auto climate control.

We do not have this option in the states.

tjnptel1 · 11-04-2008, 05:02 PM

i honestly don't see what's wrong with having it on all the time?

ncoig · 11-04-2008, 05:26 PM

Quote:

Originally Posted by GBX

lately i've been noticing that when i press auto to turn on the air, it always turns the a/c button on, regarldess of whether it was pressed when i turned off the air. Its been in the 40's outside and i hit auto and the a/c light is on. What gives?

Might be to extend the compressor life, since even in winter you should run the compressor some each month.

In my RSX of yore, it did that, too, and activating the defroster forced the compressor. There were a few keystrokes that disabled that, however. Maybe the same thing exists for the E90...

-N

E92_328i_Boston · 11-05-2008, 02:08 PM

I agree. You should run the A/C at least once every few weeks in order to condition the seals.

-A

GBX · 11-05-2008, 02:19 PM

Quote:

Originally Posted by E92_328i_Boston

I agree. You should run the A/C at least once every few weeks in order to condition the seals.

-A

yeah, but won't the snow flake being on cool the air down a bit? That's why it bugs me that its on by default. Maybe i'm wrong and the temp wont change.

ncoig · 11-05-2008, 04:05 PM

Quote:

Originally Posted by GBX

yeah, but won't the snow flake being on cool the air down a bit? That's why it bugs me that its on by default. Maybe i'm wrong and the temp wont change.

Cooler than it would otherwise be, yes, but the auto climate will adjust the heat mix to make it the proper temp anyhow.

It primarily will make the air drier.

-N

E92_328i_Boston · 11-06-2008, 09:42 AM

Having your A/C on and the temp set to the hottest will not be any cooler than the temp set to the hottest with the A/C off, will it?

-A

seanl · 11-06-2008, 12:46 PM

BTW, if I turn off the a/c compressor manually, next time I turn on the climate control fans the a/c compressor stays off. Interesting.

11-04-2008, 12:10 PM	#1
GBX Lieutenant 44 Rep 472 Posts Drives: 997.1 GT3 Join Date: Aug 2007 Location: LI, NY iTrader: (0)	A/C on by default? lately i've been noticing that when i press auto to turn on the air, it always turns the a/c button on, regarldess of whether it was pressed when i turned off the air. Its been in the 40's outside and i hit auto and the a/c light is on. What gives?
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11-04-2008, 12:24 PM	#2
satakal Major 96 Rep 1,476 Posts Drives: e46 Join Date: Nov 2007 Location: socal iTrader: (2)	ac does more than cool air... it also pulls moisture out of the air. It's ok to have the snowflake and heat. I say, "no worries".
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11-04-2008, 12:27 PM	#3
ibimmer954 Major 150 Rep 1,429 Posts Drives: '23 i4 M50, '15 M3, '18 911 Join Date: Jul 2007 Location: San Diego, California, USA iTrader: (0) Garage List 2015 BMW M3 [9.75] 2023 BMW i4 M50 [10.00] 2018 Porsche 911 C4S [0.00] 2019 BMW X4 M40i [0.00]	Yes, in cold weather the compressor will help prevent "fog" from forming on the windows by de-humdifying the air.
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11-04-2008, 01:14 PM	#5
E92_328i_Boston First Lieutenant 11 Rep 313 Posts Drives: 2008 E92 328i Join Date: Apr 2008 Location: Boston iTrader: (0)	During my 14 years of driving I have never used the A/C in the winter (live in Boston) unless my purpose is to defrost or defog the windows. I know it removes moisture from the air, but 99% of the time all I need is simply the vents on warm, pointing to my feet. Easy pizzi. Why run the A/C compressor when you don't have to? There is no doubt that it puts more of a load on the engine, all other things being equal. -A
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11-04-2008, 01:46 PM	#7
E92_328i_Boston First Lieutenant 11 Rep 313 Posts Drives: 2008 E92 328i Join Date: Apr 2008 Location: Boston iTrader: (0)	Not to mention, dirty windows are much more apt to be fogged up (in my experience). Clean your windows inside and out, very well, and very often. -A
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11-04-2008, 01:51 PM	#8
Barmats Lieutenant 17 Rep 504 Posts Drives: 2019 BMW X5 Join Date: Jan 2008 Location: CA iTrader: (4)	I keep my AC off unless I need to use it. So here in Minnesota, it's on most of the summer, but only on at other times if I need it to defrost the front window or if the humidity is high. In the winter I'll occasionally run it to defrost, but it feels like there's slightly less engine load when it's off.
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11-04-2008, 02:56 PM	#9
bsd107 Captain 46 Rep 627 Posts Drives: 2009 335i E90 Join Date: Jul 2008 Location: US iTrader: (0)	I agree I HATE this "new" feature that the A/C comes on when you hit AUTO (on my E90 LCI). The E39 5-series did NOT do this - the A/C button was completely independent of any other operation, and I greatly preferred this to the way other car companies linked it to AUTO (e.g. Honda, Lexus, VW, etc.). I can't stand it that BMW copied this approach. I would have much preferred it if they had copied all other manufacturer's approach of allowing linking the driver and passenger side temps together so you don't have to move both temperature knobs every time you want to make a change....
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11-04-2008, 03:18 PM	#10
Barmats Lieutenant 17 Rep 504 Posts Drives: 2019 BMW X5 Join Date: Jan 2008 Location: CA iTrader: (4)	This is a slight deviation from the thread, but it would also be nice if there was a way to tie the 2 front temperature zones together so when you changed the driver's side temp, the passenger side changed as well. I don't use the AUTO button very often and prefer to have manual control. But I agree - I don't like the way AC comes on automatically when you press AUTO.
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11-04-2008, 03:21 PM	#11
satakal Major 96 Rep 1,476 Posts Drives: e46 Join Date: Nov 2007 Location: socal iTrader: (2)	3 things: First, notice how its the socal guys that say its no big deal? Second, I don't understand where the passion comes from? Is it the LED being on, the loss of 1.73 hp, or is it the cost per tank of 20 cents? Third, what's winter? I'm clearly missing something.
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11-04-2008, 03:30 PM	#13
tjnptel1 Cunning Linguist 149 Rep 2,219 Posts Drives: 335i Join Date: Apr 2007 Location: Norfolk, VA iTrader: (0) Garage List 2007 335i [0.00]	it's not only our cars, all our family cars do this when you press the auto button. __________________ Bottles are for babies, Real men get blown.
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11-04-2008, 03:44 PM	#14
3er BMW Private 0 Rep 91 Posts Drives: E92 325i Join Date: Nov 2006 Location: Denmark iTrader: (0)	You people should have ordered the manual a/c and not auto climate control. You should run the compressor often for the seals not to dry out.
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11-04-2008, 05:02 PM	#16
tjnptel1 Cunning Linguist 149 Rep 2,219 Posts Drives: 335i Join Date: Apr 2007 Location: Norfolk, VA iTrader: (0) Garage List 2007 335i [0.00]	i honestly don't see what's wrong with having it on all the time? __________________ Bottles are for babies, Real men get blown.
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11-05-2008, 02:08 PM	#18
E92_328i_Boston First Lieutenant 11 Rep 313 Posts Drives: 2008 E92 328i Join Date: Apr 2008 Location: Boston iTrader: (0)	I agree. You should run the A/C at least once every few weeks in order to condition the seals. -A
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11-06-2008, 09:42 AM	#21
E92_328i_Boston First Lieutenant 11 Rep 313 Posts Drives: 2008 E92 328i Join Date: Apr 2008 Location: Boston iTrader: (0)	Having your A/C on and the temp set to the hottest will not be any cooler than the temp set to the hottest with the A/C off, will it? -A
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11-06-2008, 12:46 PM	#22
seanl Second Lieutenant 2 Rep 214 Posts Drives: '08 335i 6-Speed Join Date: Aug 2008 Location: SF iTrader: (0)	BTW, if I turn off the a/c compressor manually, next time I turn on the climate control fans the a/c compressor stays off. Interesting.
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