This, no doubt, would be a classic retort among some drivers to a suggestion to switch on the A/C, even when temperatures on the outside are hovering near the freezing mark—or even if they’re just a bit brisk. But don’t dismiss the advice out of hand—after all, your car’s air conditioning compressor doesn’t just refrigerate the air. In fact, it doesn’t even need to refrigerate it, unlike your home air conditioner, which is permanently set on “freeze.” You can dial in the heat setting on your car’s climate control while simultaneously running the air conditioner’s compressor.
It turns out that what the A/C is really good at is dehumidifying the air—and that’s the perfect thing to alleviate those fogged-in windows that develop when outside temperatures are low and interior temps aren’t. Adding the heat setting is a bonus, because it helps the human occupants of the passenger compartment, who might otherwise complain if 40° F. air were blasted at them, even if it did clear up the condensation on the windows.
Some vehicles with automatic climate control run the air conditioning compressor when the heater is on as a matter of course, but if you have a manual climate control, remember to run your air conditioner with the heater periodically, if not most of the time.
Running the air conditioner also helps keep the components from atrophying over the winter—it prevents loss of the refrigerant, and keeps up the service life by preventing expensive repairs down the road.
via Auto Channel