Smart Air (aka Smart Health) Blast Mini Mk II Air Purifier for Large Rooms up to 3,075 sq ft / 30 mins, 36-49 dBA, CARB Certified, True H13 HEPA Filter for Dust, Allergens, Pet Hair & Smoke

Absolutely love this, air quality is so much better in the house, it's super quiet, we forget it's even on its so quiet. Handles the entire house and fits perfectly in a centralized area against a wall.

This is an incredible purifier. I’m obsessed. Only unit I’m aware of that’s NOT PLASTIC. It’s very well built and definitely moves air. Worth the money. I want another one

It has 3 levels of setting. On low I can barely hear it; on medium it's still pretty quiet; and on high it's perfect fan white noise that fades into the background. I like it keep it on high during sleep because it masks some noises from upstairs. I did not observe any engine humming noise whatsoever. It works as a fan as well! Shipping is fast. I got it in 1 day without prime in California on the official website and it came well protected under the rain. It's one of the best air purifier out there. I would definitely recommend it!

Quiet and effective!

I am very disappointed by this product, which is specifically marketed to teachers as being quiet enough for classroom use. Given the hefty size and the equally hefty price tag, I was hoping that it would live up to the hype. Unfortunately, there is absolutely no way that I can teach with this on the highest setting, which is distractingly, unpleasantly loud. Even the middle setting is very iffy; maybe students wouldn't outright ask for it to be turned off, but it's still loud enough that at least some of them would find it annoying. (Honestly, I would find it annoying.) Only the lowest setting is feasible for classroom use, and even that isn't exactly ultra-quiet. On the plus side, this is clearly a solidly built machine. I haven't attempted to run any tests, but I'm willing to believe that the Blast Mini Mk II does do a good job of turning over the air. It just doesn't do it quietly enough to be appropriate for classroom use at anything other than the lowest setting, which doesn't seem likely to significantly reduce viral transmission.

We have three. They are sturdy, quieter than anything else on the market with comparable power, and move a lot of air. (Low is easy to sleep over, quieter than a new fridge.) I’ve verified both sound and airflow specs are as promised. Also nice is the flat top, which you can put stuff on. And, because it has a mechanical switch, it works with smart plugs. Ours turn on and off with timers and we mostly never think about them anymore. Less pollen, less dust, less germs, all good! The review mentioning the scary noise is describing a defect. I hope they contact the company. I had one arrive with a cosmetic defect from shipping, and they sent a replacement part for free. Customer service was good.