I have been using the Whirlpool air purifiers for many years. Yes same machines have been in operation for about 9 years,running constantly. In my opinion only the original Whirlpool filters are the most effective replacements. They are quieter and seem to be more efficient than knock-offs. I have only tried two "compatible" filters during those years, and found both to be louder due to the air flow passing through the cells, and the looser fit. I stay with the original Whirlpool filters. More expensive, but it's only a yearly purchase. Definitely recommend the true Whirlpool filter for the Whirlpool air purifier.
