Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Useless

I purchased this air filter a few weeks ago. Apart from being very noisy, it was totally ineffective. After running for two weeks, the filter still has not collected any dust! I didn't research enough before buying an air purifier, but now realize that HEPA is the only way to go if you actually want to purify your air, not just move it around.UPDATEAs a replacement purifier I purchased the Honeywell 17000 HEPA QuietCare Air Cleaner (see my review of this product). It works much better and actually removes particles etc from the air really well.I tried selling my IFD fiter on E-Bay but no one would buy it - not even for 3 dollars! What a POS!