The systemshould be left in fresh air mode under almost all conditions.
Floor cabinair recirculate car intake.
Cabin air filters will usually filter the air on either setting if located on the cabin side of the firewall.
Using the recirculation button helps get your car as cool as possible when it s hot outside and you have the a c on.
Caddyman 2010 03 11 05 51 19 utc 5 some outside air must be brought into the interior of a car or the trapped inside air gets polluted quickly enough high moisture levels and co2 levels and.
Just be sure to replace it as frequently as your manual suggests.
The outside air intakes for the heating and cooling system are at the base of the windshield.
Car s intake vent easy to find.
Automakers tout their ability to filter out dust particles smells and more.
Originally published january 13 2006 at 12 00 am.
It seems within the last 30 years or so cabin air filters have become a regular part of your vehicle.
But even in recirculation mode outside air will make its way in.
It s preferable to draw in fresh air rather than recirculate existing cabin air.
But for your wife s issue you just need to make sure you get a car with a cabin air filter and make sure you have a hepa grade filter in place.
Keeping the system in recirculation mode particularly with the a c off can cause the windows to fog up.
However filters located under the hood at the air intake will not filter recirculated air.