Over the past few years, I've tried several different humidifiers to maintain an acceptable level of humidification during the dry winter months for my collection of acoustic and electric guitars in an 11' x 16' room of my NYC apartment. The Venta LW25 Comfort Plus is the best one yet. The water capacity is very good, so, refills are not required as frequently. It is a solid, well designed and constructed unit that looks good and is very easy to refill, maintain, and clean. The option to use the Venta Water Treatment Additive seems to make a positive difference in neutralizing the hard water that comes from the tap in our sinks here (although I have not done controlled chemical tests of it, after regular use of the additive there is no evidence of the typical “white dust” that I've experienced and often has been reported when using hard water with other room humidifiers). I have discovered after five months of using it continuously that the internal mechanism does make a faint ticking sound, which other reviewers have reported; a number of people online have reported and provided instructions as to how that can be fixed fairly easily, although I have not yet tried to do so. The Venta humidifiers are more expensive than most but I think they are worth it.