Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: Piece of junk

Recently purchased this because I have asthma and need to filter my bedroom because my roommate smokes. The instructions state that the hepa filter never needs replacing...you just need to vacuum it. I vacuumed it weekly and washed the other filter at the same time. When the hepa filter isn't working, a light comes on. After two months of usage the hepa filter light is on continuosly and it is not longer effective. A total waste of money!!