Heater with A/C

You want the climate *controlled*, right? The AC doesn't cool the air; it dehumidifies the air. The climate control keeps the AC on and engages it as needed to control the climate inside the car.

Feel free to turn it off if you like.

Although the ac light is on that does not mean that the ac is actually running and using power all the time, it runs as needed to dry the air. I doubt you could notice any significant difference in gas mileage by turning it off. But you would notice the windows steaming up and the atmosphere getting fuggy !!

MrCheerful

It takes the moisture out of the air -- many newer cars automatically turn on the A/C when you hit "defrost". Driving around Sacramento and the environs in my Honda, I have the A/C on constantly in the winter to keep the windows from fogging up. (Don't have that problem in the RX330.)

Don't know about the '300, but on my '330, you can turn the A/C off on the touch screen and still use the auto climate control.