How do I know my air filter is working?Updated 14 days ago

Most particles that your air filter is capturing are too small for us to see. So even if your filter "looks" clean, it's more likely that it is full of microscopic contaminants. That said, with time, your air filter will build up a layer of gunk (from larger visible particles like dust, debris, and hair). Once you start to see that, you not only know your filter is not only working properly, but that it's definitely time to replace it.

Clean filter, Dirty filter (before and after)Keep in mind, if you replace your filter and it's not super dirty (like the picture above), that doesn't mean it's not working! A lot of the contaminants these filters capture are microscopic (the darkening of the filter is from larger, visible dust and debris particles). So just because you can't see it, it doesn't mean you aren't breathing it.