Is the Levoit Core 400S better than the Blueair 211i Max?

It depends on what you care about most.

• Pick the Blueair Blue Pure 211i Max if you want more cleaning power for a larger room. It is generally the stronger choice for bigger spaces and faster air turnover.
• Pick the Levoit Core 400S if you want a more budget-friendly option for medium-to-large rooms and value features like a built-in air quality readout.

In general, the Blueair is the better pick for performance, while the Levoit is often the better pick for value.

Before buying, verify the current CADR, recommended room size, noise level, and replacement filter pricing on the official product pages, since those details can change.