why do we use the air recirculation button for AC but not for heat.

Question

Why do we use the air recirculation for the summertime AC in the car. Then, in the wintertime, we don’t use that button?

In: 1

Answer 1

Cold air holds less moisture than warm air. In winter when you want to defrost/defog windows, you want to remove moisture by blowing DRY air at it so the dry air absorbs that moisture (like a dry sponge sucks up water Better than a wet one).

Nothing more DRY than taking DRY cold air, heating it so it can absorb the moisture stuck on the windows.