As the tiny diagram shows, the “recirculate air” button orders your A/C to stop taking in outside air, and instead recycle the air already in the car. So when should you be using it?
It’s best to recirculate air during the Three Hs: hot days, highways and high pollution. In all three cases, you and your car are much better off keeping the outside air … outside. However, you should use this button sparingly during winter months since recycling moist air can quickly fog your windows.
Overall, strategic use of this unsung feature can greatly improve your health and MPG.