BioGS 2.0 (SPA-625A White)

I purchased one minus a2 before it had wifi which is still in the bedroom, a newer wifi capable minus a2 for the outbuilding, the a3 ultra quiet for the living room and kitchen, and a bioGs2 for my ex-wife's office that had bad air quality and was able to get locked up in her office. this was over at least an eight year time period. The original still works just like day one.

RabbitAir BioGS is personal favourite.

Absolutely, very quiet on its lower settings.

RabbitAir is the only way. Ignore everyone else.

See if you can find a RabbitAir unit. Anything designed as a "smoke eater" will also be able to scrub the smell from your room while it's being occupied

Never had a problem, just rotate the filters at the recommended intervals. I think it's about every six months, I know some models say three years with regular use. It's not a smart machine that can integrate with HA, but I swear the BioGS air quality sniffer knows I'm going to fart before I do. I have it set to auto modulate the speed when it detects low air quality so it'll go from a whisper to a jet taking off for a minute as it scrubs the air. Newer ones of their base model run about $300, and the ~$700 wall mounted units are their most serious "I put this in my cigar room" level

Rabbit Air or Lichen Air. They really don’t do that well with dust, they do remove the smaller particles that get past your lungs and get into your bloodstream. We’ve had the Rabbit Air for almost 4 years, no issue, app connectivity, amazing customer service. Lichen Air about two months, two large Hepa 14 filters, no app connectivity, I feel it’s simpler but moves an amazing amount of air, wouldn’t go wrong with either.

Funnily enough the brand I like the best ($$) is called RabbitAir. A bunch of years ago I spent a long time researching and this one seemed the best. I still have the original ones I bought, they last well and function very well. Yearly filter replacement for about $100. For my office I got a Coway after learning they manufature some of the filters for RabbitAir (box said coway on it when the new ones arrived). It works well. I also learned that Korea is a mecca for clean air knowledge and remedies, and most of the best ones are manufactured there.

Rabbitair has a germ defense special filter. I’ve been using their products for 14 years. https://preview.redd.it/59agqo0x9hjg1.jpeg?width=1281&format=pjpg&auto=webp&s=98279d27f316d0c758228c41bb64579908a371e0