Discussion of A/C use in cold weather

[Jeremy3292]

So can anyone explain to me why when I have the heat on in auto mode the AC button is still on? Seems like a waste to run the AC when I have the temperature setting on HI, no? Auto mode insists that the AC is on regardless of temperature setting...

 

[Big Earl]

So can anyone explain to me why when I have the heat on in auto mode the AC button is still on? Seems like a waste to run the AC when I have the temperature setting on HI, no? Auto mode insists that the AC is on regardless of temperature setting...

It just means the AC is enabled if the system decides it needs it for dehumidification. It doesn’t necessarily mean the compressor is running.

 

[GtiMart]

I believe ac is used to dry the air, condensing the humidity.

 

[android04]

I believe ac is used to dry the air, condensing the humidity.

Yep. It keeps your glass from fogging up with your breath.

 

[Gasaraki]

So can anyone explain to me why when I have the heat on in auto mode the AC button is still on? Seems like a waste to run the AC when I have the temperature setting on HI, no? Auto mode insists that the AC is on regardless of temperature setting...

Most people don't know what "AC" means. AC is "Air Conditioning" NOT air cooler. AC doesn't necessarily have to cool the air. If you set the temperature to 80 and then manually push the AC button, the AC will work. AC works in any temperature. You use the front defroster? It turns on the AC to blow dry air on the the windshield.

 

[Mash]

If it's very cold outside, AC won't turn on. You can't dry what is already very dry.

 

[Jeremy3292]

So the car can measure humidity automatically it sounds like?

 

[Big Earl]

So the car can measure humidity automatically it sounds like?

Absolutely.

 

[GeoG]

I feel like an easy way to fix this is to have a default AC on/off toggle option in a settings menu somewhere. Should only have to hit it basically twice a year, each at the change of seasons.

Unless you are Oklahoma and it goes from 80 to 30 to 50 to 25 and back to 90. Just kidding. I agree though, a default on/off would help.

 

[GtiMart]

The thing is, in ICE cars having the AC compressor on created drag on the engine and was something you could easily feel. You would lose important power especially at lower revs. That's the only reason why I turned it off sometimes. In an EV, the compressor doesn't cause any performance problem, and I would think its consumption is low enough that you don't need to care about it.

What is the reason for wanting it off so badly?

 

[Mash]

The only reason to switch off a/c is track use to let compressor use all cooling power for battery and motors at the cost of uncomfortable ride. All other times a/c is smart enough and gets smarter with updates.

 

[NBCGLX]

Most people don't know what "AC" means. AC is "Air Conditioning" NOT air cooler. AC doesn't necessarily have to cool the air. If you set the temperature to 80 and then manually push the AC button, the AC will work. AC works in any temperature. You use the front defroster? It turns on the AC to blow dry air on the the windshield.

Every car I've owned prior to the Model Y would not engage the A/C compressor in temps below about 40F. Even if the A/C button appeared to be enabled, the compressor wouldn't actually run in cold temps. I've noticed in my Model Y that even in Auto mode, the A/C button will not be on when it's very cold outside (20s/30s). So unlike most cars with automatic HVAC, it seems the Teslas are smart enough to only use the A/C when it's actually needed, not just run it all the time.

 

[Jeremy3292]

Well today was the first day I saw the A/C off while on Auto! It came back on later though

 

[**BatteryLow**]

Yesterday at 6 celsius outside and my temp setting at manual and 15.5 celsius my 2020 M3SR+ suggested turning up the interior temp setting to 22 celsius to SAVE energy on the remaining 30 kms of my trip

 

[mtmra70]

What is the reason for wanting it off so badly?

Why run it if you don't need/want it? Modern cars make it EXTREMELY difficult to just bring in fresh air at whatever ambient temp. In my 2011 WRX, during summer months I just leave the temp set to coldest, I just want fresh air coming in at whatever ambient temp it is.

It's also annoying that in modern cars if you just turn the temp all the way down it will trigger auto/AC mode. It seems like engineers assume all we want is conditioned air in a sealed car. Many of us enjoy fresh air with the windows open