For most of us, our first car’s climate control consisted of Red / Blue, Fan / No Fan. And, we were the lord of climate in our cars. No doubt, you probably only had the temperature controls at the extremes and used the fan speed to regulate your comfort. Now, you’ve graduated to a vehicle with a button or a place on the dial labeled, "Auto."

But do you use it?

As control freaks would say, "Nope, I’ve got it." In my 18 years of selling cars, I notice that most do not take advantage of this feature and I find that they don’t know why they should.

One compelling argument for is to save fuel. Yes, really. Here is how that works: Your battery stays charged because the engine is turning the alternator. The only way the engine can do that is if we have fed it fuel. So, the more you ask of the battery, the more the engine has to keep that alternator charging it, which takes more fuel. This isn’t a huge amount, but a significant amount over our average ownership period.

At home, we set a number in the window of our thermostats and walk away. We don’t change the fan speed or the direction or the vent from where the air comes. We simply trust it to keep the space at the temperature we want. Your automatic climate control in your car will do the same; get to the temperature you want and stay there.

Here is a way to imagine how not using Auto uses fuel. Imagine every dial you turn and every button you push, is a conversation with the car. In the hot summer, you jump in, crank the temperature gauge down to 58 degrees and turn up the fan. In your mind, the car is cooling off faster. Physics thinks otherwise, but let’s move on.

Then, when you begin to feel a bit cool, you turn the fan down. Your conversation with the car is this, "I want the cabin to be at 58, but I’m only going to give you one notch of fan speed to get it there and keep it there, work that compressor as hard as you need to do that for me!" This is where we are asking more from the battery and the climate system than necessary.

In the winter, 79 degrees and full fan, now creates something you absolutely don’t want, a wind chill factor! Your engine is not warm enough to produce the heat you are requesting, so by turning the fan up, your already cold air becomes blowing, cold air! Again, it cannot physically get hotter or colder faster because we are trying to trick it with our request of the extremes.

If you set it and forget it on Auto, the temperature will get to your number as quickly as physically possible and stay there. That one button "knows" exactly what is needed to get you what you want. Even using A/C in the winter to pull moisture out of the system to make it more efficient and cut down on fogging up. All the while, your hands are on the biggest switch in the car and the systems don’t need to work harder than they should. And not working harder equals long-term fuel savings.

Try it for a week. You may be surprised.