Review on isinlive 2-Pack NEA-F1 H13 True HEPA Filter for Eureka NEA120 Air Purifier and Toshiba Feature Smart WiFi Air Purifier – Includes 8-Pack NEA-C1 Activated Carbon Replacement Filter by Tony Watts

The charcoal filters are easy to replace and when Alexa asks you to change the filter, it's the first filter to change. The carbon filter becomes almost transparent. There are four changes before you need to use a larger filter and order another set. Alexa will ask for a new filter to replace the 1st carbon filters. It looks like the charcoal filters will last a month with the cleaner at average levels. I wear them all the time because of allergies. I can't say how economical it is as it's new to me. But it's Alexa's help to send a filter change notification. A short brush with a vacuum cleaner attachment and a new activated carbon filter works.