I recently picked up one of
these room humidifiers, initially to interject some moisture into the extended stay hotel room that I'm in at the moment. The heating unit is electric and the warm air it produces is very,
very dry (I'm guessing down in the 10-20% RH range), and it was causing me sinus problems when sleeping.
The humidifier is rated for about 400 square feet (which is about the size of a standard hotel room), is pretty simple to use, and is actually nearly silent (which is saying something in my case, since I tend to have excellent hearing). The other advantage of this model it is there are no filters that have to be periodically replaced. I also picked up one of
these hygrometers, which also works well in my experience and has a magnet on the clip/stand so I can just stick it to the refrigerator in the room. Using both, I find that I rarely have to run the humidifier above the "medium" setting to keep the room around 40% RH, which seems to be comfortable for me (and is pretty good for my 414ce that I have with me; the in-case HumidiPaks do the rest).
In fact, the humidifier worked well enough that I bought a second one to keep in the room of my house in Texas where I store some of my guitars; the house has electric heat as well, so the room humidifier seems to help prolong the life of the HumidiPaks I keep in those cases.
As an aside, I've noted that Willcutt Guitars in Lexington, KY (where I'm currently working) successfully uses several different kinds of these room-sized humidifiers to augment their central system, some with a much larger capacity, some like the one I got. Their main building is an old building that was (from what I understand) once a butcher's shop. So the HVAC system probably isn't routed particularly well/efficiently; and many of the higher end guitars (Taylors, Martins, etc.) they keep on display are on the upstairs floor of the building, in smaller rooms.
