I held a four gallon bag over the top on the highest setting, and it filled up quickly; it is definitely moving enough air to work for the size of rooms advertised. The original filter insert has lasted over two months at this point in the bathroom where it gets humid from hot water and dusty from clay cat litter without the air flow decreasing noticeably. I did vacuum the filter insert once for good measure.The images show a negative ion generator, but there is none present on the actual product, which I actually consider a positive negative ions have been reported to be a potential health risk. There is no instruction about which way to put the filter insert in, foam side up or down, but I'm fairly confident that foam side up is best, and it likely doesn't matter much.