Instruct: Classify the given Amazon review as either positive or negative.
Query: Works REALLY well; louder than more expensive units

It works really well; noticeable almost immediately.It's louder than the more expensive brands, but not bad. Quiet on the slower speeds, but I doubt it's as effective. Since it was purchased for what it can do rather than noise, we always run it at full speed.Great buy for the money. Ordering a few more for other rooms.