Climate - Auto (1 Viewer)

[sum1]

Why when I press Auto does it always show that the Air con turns on? It would be nice to set the temp to 75 during the winter months and not to have to mess with it all the time (without AC turning on).

Though I did read this: Is running a car’s air conditioner in the winter good or bad? - Stonum Automotive - Longmont, CO

Is there a way to set the Auto to not turn on the AC when pressed?

 

[suprarx7nut]

AC is used for humidity control, not just temperature. You should be able to leave the AC on permanently and still have accurate temperature control with just the dial.

That's also good for the compressor and seals. AC systems can leak if the system and it's oil is not circulated on a regular basis.

Leave that AC on, unless you're "hyper-miling" or you have low humidity sensitivity issues.

 

[sum1]

AC is used for humidity control, not just temperature. You should be able to leave the AC on permanently and still have accurate temperature control with just the dial.

That's also good for the compressor and seals. AC systems can leak if the system and it's oil is not circulated on a regular basis.

Leave that AC on, unless you're "hyper-miling" or you have low humidity sensitivity issues.

Does running AC with heat suck up more gas like running AC with cold air, or just a myth?

 

[usedname]

I have the same problem - I don't care about humidity, and it seems a waste to have the AC on - I don't want my air 'conditioned' except for getting the right mix of cool outside air and heated air. I wish we simply had sliders or knobs without an actual temp control, I feel those are more accurate, and much easier to adjust than futzing with the temp up/down buttons. This is even more true if your daily temps fluctuate enough that you want hot air in the morning and cooler air in the afternoon. It's even worse because half the buttons are physical buttons and the other half are touchscreen. Infuriating UI.

And as far as that link recommending using the AC in the winter - that's silly. You can run the AC probably once a month and no longer have any of the problems that it suggests you would have from not running the AC.

 

[saucebox]

Does running AC with heat suck up more gas like running AC with cold air, or just a myth?

Myth

 

[suprarx7nut]

Does running AC with heat suck up more gas like running AC with cold air, or just a myth?

A little, but it's probably not enough to notice. We're talking 0.1-0.5 MPG at best, probably less.

I have the same problem - I don't care about humidity, and it seems a waste to have the AC on - I don't want my air 'conditioned' except for getting the right mix of cool outside air and heated air. I wish we simply had sliders or knobs without an actual temp control, I feel those are more accurate, and much easier to adjust than futzing with the temp up/down buttons. This is even more true if your daily temps fluctuate enough that you want hot air in the morning and cooler air in the afternoon. It's even worse because half the buttons are physical buttons and the other half are touchscreen. Infuriating UI.

And as far as that link recommending using the AC in the winter - that's silly. You can run the AC probably once a month and no longer have any of the problems that it suggests you would have from not running the AC.

I wonder if the Lexus system has some different tweaks. My 99 LC is generally hands off, year round. I move the temp dial between 70 and 74 in the winter and maybe 73-77 in the summer and keep AC on always. I very rarely have to touch anything. It's very "automatic".

The problem with trying to run it once a month is most people will just forget. They'll turn it off in early winter and turn it back on the next time they get too hot which could be spring. That's a lot of potential time to let seals dry out. A minor AC leak fix will cost a lot more than the extra gasoline consumed by running the AC compressor for years. I think this is a part of why the default setting on almost all vehicles is to leave AC on in an auto-AC system. The benefits far out-weight the negatives.

AC also helps dramatically in defogging windows, especially in cold and humid climates. This is a part of the "conditioning" performed by the system and why lower humidity is desirable. Often times the defroster/defogger and windshield vent controls are linked to the AC clutch, sometimes even on cars without "auto-AC". Manufacturers do this because the dehumidifying aspect of the AC system is very helpful in defogging.

One more thing to keep in mind is that the clutch cycles on and off even if the AC button is "on". The light doesn't mean you are constantly compressing the system at maximum capacity. It just means the clutch is allowed to engage when the auto-program thinks it's helpful. When it's cold outside the AC compressor will not be active most the time.

Many people associate Air Conditioning with cold air, but automotive and commercial HVAC systems use AC in a broader way.

 

[sum1]

A little, but it's probably not enough to notice. We're talking 0.1-0.5 MPG at best, probably less.



I wonder if the Lexus system has some different tweaks. My 99 LC is generally hands off, year round. I move the temp dial between 70 and 74 in the winter and maybe 73-77 in the summer and keep AC on always. I very rarely have to touch anything. It's very "automatic".

The problem with trying to run it once a month is most people will just forget. They'll turn it off in early winter and turn it back on the next time they get too hot which could be spring. That's a lot of potential time to let seals dry out. A minor AC leak fix will cost a lot more than the extra gasoline consumed by running the AC compressor for years. I think this is a part of why the default setting on almost all vehicles is to leave AC on in an auto-AC system. The benefits far out-weight the negatives.

AC also helps dramatically in defogging windows, especially in cold and humid climates. This is a part of the "conditioning" performed by the system and why lower humidity is desirable. Often times the defroster/defogger and windshield vent controls are linked to the AC clutch, sometimes even on cars without "auto-AC". Manufacturers do this because the dehumidifying aspect of the AC system is very helpful in defogging.

One more thing to keep in mind is that the clutch cycles on and off even if the AC button is "on". The light doesn't mean you are constantly compressing the system at maximum capacity. It just means the clutch is allowed to engage when the auto-program thinks it's helpful. When it's cold outside the AC compressor will not be active most the time.

Many people associate Air Conditioning with cold air, but automotive and commercial HVAC systems use AC in a broader way.

Great explanation, thanks for clarifying

 

[saucebox]

Mea culpa. @suprarx7nut is right—small (but definitely noticeable) change in mileage. Not a myth, at least according to Consumer Reports.