Blueair Blue Pure 211i Max vs Winix 5500-2

The 211i Max covers 750 sq ft at 4 air changes per hour — that's not a marketing number, CNET's lab confirmed it. The Winix 5500-2 is rated for around 360 sq ft at the same ACH standard. If you're trying to clean a large open-plan space, the Winix simply can't keep up, and running it on max in a room it's undersized for wastes energy and wears out filters faster. But if your room is under 400 sq ft, you're paying for coverage you'll never use with the Blueair.

The 5500-2 has a built-in particle sensor and auto mode that ramps the fan up when it detects pollution and dials it back when the air is clean. This isn't a gimmick — it means the purifier is actually responding to your environment instead of running at a fixed speed you set and forget. The Blueair has no sensor, no auto mode, and no app on this model. You set the speed manually and that's it. For all-day passive use, the Winix's auto mode saves energy and extends filter life.

Blueair replacement filters for the 211i Max run $50–$70 per set, and you're replacing them every 6–12 months depending on use. Winix filters are consistently $30–$40 and widely available on Amazon. Over three years of ownership, that gap compounds into $60–$90 in savings on filters alone — nearly closing the upfront price difference entirely. The Blueair's washable fabric pre-filter helps, but it doesn't offset the higher cost of the main HEPA filter replacement.

The Winix 5500-2 includes PlasmaWave technology, which generates trace amounts of ozone as a byproduct. Winix says it's within safe limits, and you can disable it entirely — but you have to know to do that. If you have asthma, respiratory sensitivities, or pets, you should turn PlasmaWave off immediately and just run it as a standard HEPA filter. The Blueair has no such feature and no such concern. It's a minor issue for most people, but it's a real one that the Winix's marketing undersells.