My wife and I have an ongoing disagreement regarding the use of the car’s windshield defroster. We live in Colorado and time and again it gets very cold. Today for example, it was so cold that even though it was raining, the rain was instantly freezing to the windshield. Obviously, I am using the car’s defrost and it is blowing at full force.

Here is where the disagreement begins. I believe that I need to press the hot button, so that the car will blow hot air instead of cold air so that the defrost will “heat up” the windshield, melt the ice that is frozen and then let my windshield wipers take care of the rest. However, my wife tells me that I am stupid, she says that all cars automatically blow cold air and that even on freezing cold days, that I should not manually force the car to blow hot air.

We have agreed to disagree - kind of - on this one. When it is really cold, like on a day like today, who is right? Should I continue to force the car to blow hot air, or is my wife right and should I allow the car to blow cold air? Please note, that this is after I have already scraped the ice off the windshield, and particularly on days when it is raining, and it is so cold that the rain then freezes to my windshield.

Thank you very much for your time and hopefully you can help us settle an ongoing disagreement.

Arnold Lewis

Boulder, Colorado

Select the hot air.
The A/C compressor will run also, this is a dehumidifying measure.
If you are starting with a cold car the air will naturally be cold to start with, then warm up.

You want as much hot air as possible. What is the “hot button?” I live in Minnesota and could use a “hot button.”

Why would a car blow cold air? If the heater core is warmed up and the temp inside the cabin is cooler than what you have the climate control set for, the defroster is going to try and blow hot air. Why would it blow cold air unless the anti-freeze/coolant hasn’t warmed up yet?

Never mind…

The “hot button” basically turns the AC off. When I turn the defrost on, it automatically puts the AC on and I have to turn it off.

Okay, you lose. Wife wins.

Leave the AC on. If it runs at all, it will help to dry the air. The heater way overpowers the AC, so it won’t make it take any longer to warm up. Generally, if it is below freezing the AC won’t run much anyway. It will just cycle on for a short time every so often.