Contact
Two people keep this catalog, and both of them read this box. There is no office, no support desk and no form letter waiting at the other end of it — a reply comes from whichever of us is nearer the data file.
There is no filter-deal newsletter here to be signed up to, and no other list either. Your address carries one reply and is then about as much use to this site as a spent HEPA cartridge — it is never sold, shared, or kept for anything.
What people actually write in about
Most of it is a number. A smoke CADR that changed when AHAM re-certified the model and the old figure is still sitting in our table. A filter that was quietly revised mid-generation, so the part number on the page no longer buys a cartridge that fits. An annual filter cost that made sense a year ago and does not now. A purifier we have never listed — a commercial box, a regional model, a Corsi-Rosenthal build worth a column of its own.
Where a sourced CADR correction lands
A correction with a source attached gets edited into airpurifiers.json, which is the only place any spec on this site lives. The unit page, its room class, every head-to-head it appears in and the date under the catalog all re-render from that one edit. The specs currently read August 2026.
Two things we will say no to
A star rating we cannot attribute to a named non-Amazon retailer, because an uncited rating is a claim about customers who may not exist. And a CADR for the 7 machines whose makers decline to publish one — a confident-looking figure in a CFM column does more damage than an empty cell. Brands asking about placement get the same answer: nothing on this site is for sale, including the order of it.
If the question is really about CADR
How We Compare answers why a rating is missing or a coverage figure looks low next to the carton. About covers who keeps the 44 entries and where the numbers are transcribed from.