I've had my '24 350h for about 5 weeks. Like most of the country, we've had some very frigid temps lately. I've noticed something odd. With climate on 'Auto', set to 72°, I'm getting cold air in my face. I think the air is coming from the windshield defrost vents. Also, it seems some air is always coming out of the defrost vents, no matter where I have the air manually directed to. Anyone else noticed this?

 

Not that I've noticed, but my idea of cold air might be considerably different than yours (anything above 35F is toasty for me this time of year, LOL). The auto setting as well is a complex beast, its not just a dumb setting that pumps in warm air when the inside temp is below the setting or cold air when the inside temp is above the setting. It factors in many sensor inputs that can make one person's 72F react quite differently than another person's 72F even given the same environmental temps. Things like humidity and even being sunny, cloudy, or night time can change system functions. It tries to anticipate and adapt to human sensations, for example, bright sunny days you may find the system selects a somewhat cooler output air temp to adjust to the fact you are getting some direct heating from solar radiation. Of course, you may have an issue with the car, idk, but just something to consider as you investigate further. If it interests you, here is the formula for output temp calculation taken from a somewhat older Toyota technician training manual. I'm sure it's probably gotten even more complex now (and that's not even considering the infamous S-Flow settings). And I think, even on manual vent selection I think there is always at least a bit of air flowing on the windshield to prevent fogging (which may also call in the AC system to dehumidify air even when its not hot outside).



Stay Frosty, er, I guess I should say, stay warm.

 

The car will maintain the ambient interior temperature at what you set. When it is cold outside the glasses all around the car are cold. There is radiant heat transfer from the body to the glass which is cold. This makes it feel colder.

I usually like temperatures of around 22.5 C (72F), but when it is really cold outside (like these past few days) I set the car at 24 or 24.5 C (75-76 F). This also makes the seats toastier and the steering stays warm longer.

 

This is what I was thinking. The vehicle, probably depending on outside temp, is sending some air to the windshield. A very cold windshield is cooling the air.