[cptskippy]

> I believe most newer cars do this and there are good reasons for it.

That's an incredibly vague and dismissive statement to support lazy engineering.

If the intent is something like preventing CO2 build up in the cabin then they could periodically open the mixing value when the car is set to recirculation to refresh the cabin air.

It doesn't have to be a binary control. I've owned cars with manual mixing valves to let you control the amount of outside air gets circulated into the cabin.

[imp0cat]

I am aware of a recent youtube video where some guy measured the CO2 ppm scores with recirculation on. The results are (obviously) quite terrible after a while.

But I don't think car manufacturers care about that. I think the switch to fresh air after a while is mainly to prevent the windshield from fogging up.

[cptskippy]

Which is also absurd because other automakers have other less annoying options. I had Hondas that just vented outside air just to the defroster vents without disabling the re-circulator. The Tesla Model 3 can send heated or AC chilled air to the defroster by tapping the defroster button to cycle options.