[odensc]

What is that calculation based off of? The article lists the 4 filters as $70 (which I'd assume you would replace all at once).

The Levoit uses 1 filter "unit", and filters are $55 for a 2-pack on Amazon ($27.5/ea), or half that if you trust the third-party ones.

Levoit recommends to replace the filters every 6-8 months, so you could get 12-16 months of filtration for $55. I can't find any calculation in the article for how long the author estimates their filters would last.