Well, not really. What advantage is there to be gained by leaving the ambient temperature in exactly the same place, then adjusting the temperature of just the main vents? If you get in the car wearing heavy winter wear and the ambient temp is on 25C, you'll just end up sitting in an uncomfortably warm car with the main vents blowing at you in a lower temperature. Why not just...adjust the climate control to a more comfortable ambient temperature for your current attire/situation/preference?
If the car is maintaining a comfortable temperature of 21C, but you find it uncomfortable, then surely it's not a comfortable temperature...why override it,when you can just change it?
This is what I mean about people not really ‘getting’ it. Why would you have it set to 25c? You wouldn’t. It isn’t going to make it any more toasty warm in winter nor is it going to heat up any quicker when its cold. It’s a main thermostat setting – you don’t constantly adjust your home central heating thermostat do you? You don’t set your home thermostat to 25c do you? You might manually turn a radiator up from time to time but that’s not the same thing as adjusting the main system attempt randomly every time your mood changes.
21c (+/- 1c) is generally recognised as the optimal ambient temperature for people. So, the system stays set to this and maintains that, if you get in a freezing cold car it’ll heat the car up and be toasty and warm on the way to doing that and then gradually reduce the vent temp as it approaches it. So you get the toasty warm effect in winter. If it’s hot outside and a sauna inside it’ll cool the car with chilled air in exactly the same way. It even adjusts for the effect of solar gain. It just works.
Obviously sometimes we want to deviate from this – you’ve been for a run and you are hot, you want cold air. You don’t need to change it to 16c to get this, you can just over-ride the main vent with only cold air. Bingo – blast of cold air. Ditto if you want it a bit hotter than normal or something.
Continually changing the temp dial just seems to defeat the point of AUTOMATIC climate control, plus it isn’t even that efficient. Unless you dramatically change it, adjusting from 21c to 19c isn’t going to suddenly blast you with ice cold air, whereas the vent control allows you to do that if you wish.
Obviously this might differ in a more basic setup but in a decent system you set it up once – to your preferences – and forget about it. It takes care of everything else automatically, if your window fogs up the fogging sensor detects this and diverts air over the screen without you needing to intervene. If the sun is making it feel hotter inside than usual it detects this and blows colder air, etc etc.
This is how I work mine – I set everything to auto, 21c and then never need to touch the climate panel ever again. It’s actually frustrating to have to constantly fiddle with the main temp setting in cars with a less useful system installed.