Blue Pure 511i Max

My spec is 511i and Amazon lists it as available however when I order it they give me the wrong one, they give me the 511 one which doesn’t fit my purifier. I have gone in person to blueair trusted sellers and they have also given me the wrong one

I just bought a blueair 511i Max because it's supposed to be the quietest and I'm underwhelmed. I bought it for a small living room to keep the air fresh and it seems to create a dusty odor instead? There's also an audible machine whir even on the lowest setting. I'm considering sending it back and

Medify MA-25 is stronger for smoke; Blueair 511i is only good for small rooms Any idea why the Blueair is more expensive than the Medify, though?

The sensors onboard almost all consumer-grade air purifiers are very cheap and inaccurate. For example, a good consumer-grade AQI monitor like the AirGradient ONE is approximately $230 USD or £173 (I'm just converting currency on my end; stockists in the UK may have higher prices). Outdoor AQI can c