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In general, does air recirculated in the cabin (i.e. when the re-circulate button is engaged on the dash) pass again through the cabin air filter?

I know that the cabin air filter filters outside air before it enters the passenger space, but is it also used in closed re-circulation?

Specifically: I have a 2006 Honda Civic which only has 1 filter. Am I re-filtering the air as I'm running it on re-circulate mode?

While I'd like to think the air is getting continually filtered, I also don't think it's a good idea to pass cabin air back over all the leaves and pollen and crap the filter took out in the first place, probably makes things worse.

The filter I changed was in the glove box and it had leaves and twigs and all kinds of stuff in it, so I know it is filtering outside air. It seems counter-intuitive to send inside air back over all the garbage in the filter.

Pᴀᴜʟsᴛᴇʀ2
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Wilbur Whateley
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1 Answers1

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Cabin air filters will usually filter the air on either setting if located on the cabin side of the firewall. But even in recirculation mode, outside air will make its way in. Just be sure to replace it as frequently as your manual suggests. However, filters located under the hood at the air intake will not filter recirculated air.

Edit: I decided to look for confirmation and found this:

http://www.autos.com/auto-repair/how-does-a-cabin-air-filter-work

I can also add links to confirm that a little bit of outside air will still make its way in on recirculation mode if it's necessary.

Mustangguy809
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