I purchased 2 Bionaire humidifiers (BCM5520RC). They humidify beautifully as long as the filters work. However, the filters last 3 weeks at best using the instructions in the manual and not a moment longer. I wrote to Bionaire, to Holmes (who manufactures both the filter and the humidifier, and to Lowe's (where I purchased the product) advising them that the cost of the filter's are prohibitive to the running of the equipment. Of the three e-mails I sent, each received the automated "We will get back to you within 24 hours". Thus far 6 weeks has passed and I have received no additional correspondence. To my letters saying that their 24 hours was up long ago, I get the same "We will get back to you within 24 hours".
A box of 6 filers (an odd number because you need 4 in the humidifier) costs $24.50. I need 4 filters every 3 weeks. Hence, I buy a box of filters every month for 4 months minimum. Double this because I own two of the Bionaire Humidifiers. That means, this equipment costs me no less than $260 a season to humidify the area. Nothing I have done extends the life of these filters including using filtered water. So let me say to one and all that unless money isn't an issue - the Bionaire humidifier and filters is not a good investment. Try someone else's product.