Question about Venta LW45 Original

The humidifier is a cold evaporator - i.e. it does not need a hygrostat at all - the air cannot become oversaturated as with a warm evaporator - ideal air humidification is achieved automatically (provided the capacity is large enough for the room size). This is at least what I know theoretically about it. We always have ideal humidity.
I myself have 4 Venta air washers and am very satisfied with them. In the last few years I have tried all kinds of models from warm evaporators, nebulisers to various cold evaporators with and without filters - none of them convinced me until I came to Venta. The air washer works reliably, is easy to maintain - super easy to clean. It needs a little cleaning (rinsing) every 14 days and a small amount of hygienic agent.
The only minus point (certainly also depending on the water hardness) - sometimes a little limescale collects on the "gearwheel" where the evaporator disc is turned - then it can be that an annoying "crackling" occurs during operation which can be disturbing at night. Sometimes you have to clean it with a brush. Sometimes the drive also "cracks" - but a small spray of silicone lubricant helps here. Often, however, operation at the highest level for 2-3 hours helps, then the cracking goes away by itself. (Our units are usually operated at the lowest level - because they are in the bedroom) But this rarely happens.
All in all, I can unreservedly recommend the Venta air washer - I have really been annoyed with many humidifiers - I think there is nothing better.

I agree with doktorhaus: you don't need a hygrostat, because supersaturation is not possible with the Venta! Even completely saturated room air (as hwschwaninger writes) is not possible. For the grand piano (and the antique furniture), one Venta (or several, depending on the size of the room) is perfectly adequate. The Venta is preferable to the Stadler because it is more efficient.

Thank you very much for the two comments. Because of my grand piano (and antique furniture), my piano tuner recommended a humidifier with a hygrostat so that the air humidity remains as fixed and constant as possible even in my absence. I am now leaning towards the "Stadler Form Oskar" (evaporator), which also did well in the Kassensturz test (Venta was the test winner), especially with regard to hygiene/contamination.

Well, I think you need a hygrometer to monitor the humidity. I don't always want completely saturated room air. I want a water content of about 7 to 10 g/m3 of air, and depending on the temperature, the % of humidity changes. I can vary this somewhat with the three power settings on the unit. I have also not found a better device to date. With fogging or evaporation devices, everything within a radius of about 2 metres is always wet.