Because the humidity level in the flat is quite low — about 20, when the ideal range is from 40 to 70 and heating tends to dry things out a lot, this was purchased in preparation for the birth of a kid. Because the device is so easy to use, I didn't even bother to remove the instructions from the packaging: After adding three liters of water, I switched the machine on. After a few of hours, the humidity reached 30, but almost immediately after that, it became much easier to breathe! I had no ideSee full review