[albertw]

Originally Posted by Sportstick

The engineers at BMW who designed the HVAC system know far better than anyone here when the system should operate, or not, to preserve its function free of organism growth which causes smells. Takinng it manually out of AUTO function or tampering with it is asking for premature problems.

It's odd that you don't apply the same reasoning to other issues, like suspension modifications (which can make the car more fun to drive) and LSDs (which make it less fun to drive if you like oversteer on public roads).

I have trouble seeing how having no condensation forming at all in the air conditioning system for the 8 months a year I don't need it can be worse than having condensation form every time the air conditioner runs unnecessarily during those months and then having it run a dry cycle to remove it.

[Sportstick]

Originally Posted by albertw

It's odd that you don't apply the same reasoning to other issues, like suspension modifications (which can make the car more fun to drive) and LSDs (which make it less fun to drive if you like oversteer on public roads).

I have trouble seeing how having no condensation forming at all in the air conditioning system for the 8 months a year I don't need it can be worse than having condensation form every time the air conditioner runs unnecessarily during those months and then having it run a dry cycle to remove it.

As with most other issues, it's a risk:benefit decision. I think most of us already know/understand the effect of stiffer springs, swapping a lower control arm, adding a tune. OTOH, I think there is very little knowledge on this forum about the unknown effects/unintended consequences of altering HVAC and the details of how that is optimally programmed to function without deteriorating performance, including the growth of mold/bacteria. Just the discussion about "outside air" would seem to support that.

Given the minuscule, if even noticeable, effect of letting the system remain in AUTO all year, versus the downside of trying to out-think when it should operate, it seems more a personal philosophical concern ("it should be off") than a real-world practical need. What little I know came from learning from HVAC engineers at the car company where I spend a few decades in my pre-retirement career. It becomes a case of knowing one's limitations. If you have specific training or other expertise to know the effect of trying to only periodically manage excess humidity (using AUTO with compressor activity) in an environment where the off condition remains ambient humidity, above that of allowing periodic automatic drying, then you may have a case to make. I don't. I have had cars in the distant past where HVAC systems have developed the musty/rotten locker room odor, requiring significant intervention. With the possible downside of trying to fully clean/de-odorize the entire HVAC system, I can see no case for the benefit outweighing the risk.

[morphomeman]

Climate is also an issue. If, like me, you live by the ocean, where, even today, at 17F, the relative humidity is 53%, and most if the time it is over 70%, then keeping the AC on makes sense. But albertw lives somewhere in Canada. If he is on the prairies, then it is much less humid than here most of the year, so for him it may make sense not to use the AC as a dehimidifier year-round, the way I do.
Everything is context-sensitive.

[aerobod]

Originally Posted by morphomeman

Climate is also an issue. If, like me, you live by the ocean, where, even today, at 17F, the relative humidity is 53%, and most if the time it is over 70%, then keeping the AC on makes sense. But albertw lives somewhere in Canada. If he is on the prairies, then it is much less humid than here most of the year, so for him it may make sense not to use the AC as a dehimidifier year-round, the way I do.
Everything is context-sensitive.

In many modern cars there is no "off" or "on" for the A/C compressor as such, as a variable displacement pump is used. Due to this configuration the system can adjust infinitely from no air conditioning to maximum, so you don't get bursts of air conditioned air that is a characteristic of older fixed displacement systems that or either on or off.

I also live on the Canadian Prairies and leave the system on auto all year round to good effect, whether the temperature is +35°C or -35°C.

[Sportstick]

Originally Posted by morphomeman

so for him it may make sense not to use the AC as a dehimidifier year-round, the way I do.

This is exactly the point, it "may" or it may not, and the benefits of not using it are almost invisible, with the longer-term outcome to the HVAC system at risk for the foul odor problem. Why try to out-think a complex system/algorithm that was developed and tested across multiple continents/climates for no real gain? Sometimes, our need to be "in control" and think we know better results in negative outcomes.

[albertw]

Water vapor condenses on surfaces only if they are colder than ambient, even at near 100% humidity. It's hard to see the HVAC system being colder than ambient as long as the air conditioner compressor is OFF.

Fog is a different issue. It can be deposited on surfaces that move through it, or on the HVAC system as it's pulled through. Only heat will evaporate the water under these conditions. I doubt very much that the Germans are smart enough to design a system that knows it's foggy out, but I could be wrong. I would rather turn the heat on manually to keep the system dry in foggy conditions. Where I live it's never foggy and warm enough that I can't run a bit of heat.

I've never tried the auto setting in this car, but every other car I've had did really annoying things with the fan speed and heat distribution in auto. I like a cool breeze on my face and warm air on the rest of my body. The auto setting always messed with that setup. Turning the fan to max for no reason is really annoying if the air hitting your face is cold.

When I need the air conditioner, I turn it off and the fan to max 15 minutes before I stop, and I've never had a problem with HVAC odor since I started doing that. I suppose if I lived where the ambient temperature can be high enough that 15 minutes without air conditioning would be uncomfortable, or it was so humid that only heat would dry out the HVAC, I would try the auto setting, but I don't so I don't.

[aerobod]

Originally Posted by albertw

I like a cool breeze on my face and warm air on the rest of my body. The auto setting always messed with that setup.
.

The temperature distribution thumbwheel between the centre vents accomplishes that when the system is in auto.

[paposalsa]

Today went to pick up my clothes at the Dry Cleaner when looking for the hanger hook I found a little hook behind the driver side.
That hook is a far cry from any other hanger hook. Also noticed there is no "oh shit" handle bar where most hanger hook are located in other cars, usually on the passenger side..

[dradernh]

Originally Posted by paposalsa

Today went to pick up my clothes at the Dry Cleaner when looking for the hanger hook I found a little hook behind the driver side.
That hook is a far cry from any other hanger hook. Also noticed there is no "oh shit" handle bar where most hanger hook are located in other cars, usually on the passenger side..

Yes, and as you might expect, both of these issues have been noted before.

The clothes hook issue has a solution of a sort that can be seen on this page:

https://www.shopbmwusa.com/ACCESSORI...AT-ACCESSORIES

I don't know of a solution for the missing grab handle(s). I suppose if an owner felt a strong enough need for one, a body shop or a fabrication shop might be able to come up with a solution that looked satisfactory.

[aerobod]

Originally Posted by dradernh

I don't know of a solution for the missing grab handle(s). I suppose if an owner felt a strong enough need for one, a body shop or a fabrication shop might be able to come up with a solution that looked satisfactory.

The seat width adjustment can hold the passenger and driver in place in the seats, so less of a need for a grab handle to steady the upper body in hard cornering.

[morphomeman]

Clothes hook: I bought two little universal hooks that go over the post of the headrest, one in each of our cars. Total cost about ten bucks. Totally worth it!

[Xi-Xi]

Originally Posted by morphomeman

Climate is also an issue. If, like me, you live by the ocean, where, even today, at 17F, the relative humidity is 53%, and most if the time it is over 70%, then keeping the AC on makes sense. But albertw lives somewhere in Canada. If he is on the prairies, then it is much less humid than here most of the year, so for him it may make sense not to use the AC as a dehimidifier year-round, the way I do.
Everything is context-sensitive.

Wherever anyone lives, Canada or not, I can think of no logical reason not to have the A/C engaged year round, 24/7.

[doseL]

While we're talking about climate control - do we still need to turn off HVAC a few minutes before reaching destination to prevent any smell from condensation, even if it's in auto mode with A/C on at all times?

[Sportstick]

Originally Posted by doseL

While we're talking about climate control - do we still need to turn off HVAC a few minutes before reaching destination to prevent any smell from condensation, even if it's in auto mode with A/C on at all times?

No. That is part of the elegance of the original software and engineering. Just AUTO and drive.

[Hpirx]

Originally Posted by Sportstick

All of the air coming into the car is "outside air". From where else would it be sourced? If you open a window, the air blows in through the window opening. The air from the instrument panel has blown in through venting, aided by a fan for more speed. Nevertheless, all "outside air".

There is no reason to turn the system off from AUTO (unless MAX AC or DEFROST is needed temporarily). Just choose the temperature you want and let the system perform as designed. That performance also includes an automatic drying cycle to prevent mold growth that sometimes gives rise to odd odors, which others have reported, notably those who like to fiddle with the on/off/auto function. There is a small dial in the center, below the vents which allows you to easily moderate the temperature of the face-level airflow (from outside!) from warmer to cooler.

The HVAC system does not "add condensation". It has no independent source of moisture to add humidity. It does have the capability to remove humidity, if the compressor is cycling.

The bottom line is to set it at AUTO when taking new car delivery and except for the extremes of MAX AC or DEFROST, leave it alone! The benefits outweigh the downside. Just adjust the temperature set-point to preference and let the BMW HVAC engineers' hard work take care of keeping you comfortable.

Originally Posted by Sportstick

.

The bottom line is to set it at AUTO when taking new car delivery and except for the extremes of MAX AC or DEFROST, leave it alone! The benefits outweigh the downside. Just adjust the temperature set-point to preference and let the BMW HVAC engineers' hard work take care of keeping you comfortable.

Thanks for this admonition!
It took some discipline not to futz around with the climate control and even more to convince my wife to do the same!
But yes, the engineering really works and we have remained comfortable under a variety of conditions without playing with buttons. Only the center knob gets twiddled for fine tuning and for control freak nostalgia.

[albertw]

Originally Posted by Sportstick

The HVAC system does not "add condensation".

Since it looks like the "Auto" fanboys are never going to shut up, it's worth repeating that this part of their argument is absolute and total nonsense.

Makes you wonder about the rest of their message, if they can't even understand how condensation happens.

[DaleHeinz]

Originally Posted by Hpirx

Thanks for this admonition!
It took some discipline not to futz around with the climate control and even more to convince my wife to do the same!
But yes, the engineering really works and we have remained comfortable under a variety of conditions without playing with buttons. Only the center knob gets twiddled for fine tuning and for control freak nostalgia.

Exactly. I only really use the vent dial on the dash now.

It took some time, coming from a basic Honda HVAC system, but I've learned that this one operates much like one in a home. It's goal is to make the environment the requested temperature, not to make the expelled vent air the requested temperature.

Patients is key when wanting a different temperature overall, but with practice, you can have temporary satisfaction by modifying the degree dial.

[morphomeman]

Fans of the little wheel in the middle that adjusts the relative temperature of the center vents may have need for concern. In the last month, I have had two 2019 loaners, an X2 and and X3. Neither had the little wheel!

[Sportstick]

Originally Posted by albertw

Since it looks like the "Auto" fanboys are never going to shut up, it's worth repeating that this part of their argument is absolute and total nonsense.

Makes you wonder about the rest of their message, if they can't even understand how condensation happens.

I'm not going to descend to name-calling or venom. You're entitled to your skepticism. All points have been made and readers here can decide whether to believe any of us anonymous forum posters or rely on using their car in the manner BMW engineered it.

[albertw]

Originally Posted by Sportstick

All points have been made and readers here can decide whether to believe any of us anonymous forum posters or rely on using their car in the manner BMW engineered it.

Challenge accepted!

1. The owners manual for my car describes both manual and automatic operation. I just reread the section to confirm that there is no recommendation for either.

2. My owners manual says nothing about a system that automatically dries the HVAC system after the engine is turned off. Maybe such a system exists, but the only evidence I have for that is "anonymous forum posters".

3. This model hasn't been out long enough that anyone can know that over my target ownership of 10 years the automatic drying system, if it exists, works as well as properly using the manual settings to dry out the system before turning off the engine.

[morphomeman]

This particular model has only been around for six model years but I doubt that any aspect of the A/C is unique to it.
Some of us like the luxury of not having to adjust the climate control. Set it and forget it! Others prefer to do it themselves. Neither side appears to be harming anyone.
Let's call it a draw.

[Xi-Xi]

Originally Posted by albertw

It's odd that you don't apply the same reasoning to other issues, like suspension modifications (which can make the car more fun to drive) and LSDs (which make it less fun to drive if you like oversteer on public roads).

I have trouble seeing how having no condensation forming at all in the air conditioning system for the 8 months a year I don't need it can be worse than having condensation form every time the air conditioner runs unnecessarily during those months and then having it run a dry cycle to remove it.

By what manner does the A/C somehow add condensation to the interior of the car or to the HVAC system itself?