A professional online on youtube pointed out that the specs for a humidifier has a dl amount of moisture added per hour I think it was. So 200 dl unheated and 400 dl heated I read in a manual for something I ordered, presumably on the lower scale of efficiency.

The same guy pointed out that houses with ventilation systems also have more dry air, as the air is efficiently moved out of the apartment, reducing the efficiency of any humidifier working, the guy recommending using two humidifiers. :|

I have a small digital hygrostat measuring relative air humidity, but below 30% the meter stopps giving any value, so low air humidity presumably, but probably not less than 20% or I would feel it in my nose/throat. Ideally I would want 40% air humidity, should be good for my guitars that hang halfway up on the wall.

Says in the manual that the humidifier must stand on a "water repellent" surface, so some excessive mositure will fall onto the floor I think. What happened when I placed a water vaporizer on the floor. Did not keep using that one after trying it for a few moments.

I recently laced an order for a humidifier with a hepa filter, but I don't know how well it will be. Hepa filters can be expensive, but I guess worth it in the winter months when the air is too dry.