I bought this last week because my skin and lips are very dry, and I often have dry mouth at night, although I try to drink as much water as possible during the day. I like to use this humidifier, especially overnight, it feels more comfortable and moisturized, my breathing becomes easier, and it also makes my skin feel cooler, which is very easy to use. The red light is on during empty time. It is easy to fill, and I use pure water.