Venta humidifiers
Venta has 2 units here, from $400 to $530, across one type. 2 of the 2 cannot produce white dust.
Eight watts at full speed, no wick and no filter - Venta's disc-stack airwasher costs a great deal up front and almost nothing to run, which is the whole argument for it. Its manual is also the only one in this catalog that states the assumption behind its room-size figure: "listed square feet are based on 8-foot ceilings". That single sentence is more transparency than the rest of the category manages combined. What Venta will not tell you is how much water it actually moves - no output rate appears in the manual or on the product page - so the 485 sq ft figure has nothing behind it that a buyer can check.
The LW25's larger sibling: a 3-gallon basin, the same disc stack and eight watts at full speed, sold for 645 sq ft. Like the LW25 it comes with no output rate - not on Venta's product page and not in the LW15/LW25/LW45 manual - so the 645 sq ft has nothing behind it a buyer can check; the three gallons a day some retailers quote belongs to the older Venta Original LW45. Venta has since moved on: its US store shows both colours out of stock and names the AH550/AH555 Original Connect as the newer model. No wick, a two-year limited warranty, and a basin you will have your hands in every couple of weeks.