## Why humidify? The optimum humidity level for comfortable well-being is 40–60 %. When we heat a house during the cold season, we make the air drier. When the air is dry, water evaporates more actively from all surfaces, including skin and mucous membranes. Because of the lack of humidity, microcracks can appear, through which aggressive environmental microflora easily penetrate the body and lead to the formation of inflammation foci. That is why in this period people are more often ill with acute respiratory [infections](https://ul.orna.me/KOge/librarydisease?id=7) and suffer from exacerbation of chronic diseases of the upper respiratory tract, lungs, and [skin](https://ul.orna.me/KOge/librarydisease?id=23). ## Why humidifiers do not humidify According to studies, the installation of humidifiers does not lead to a decrease in the incidence of disease. The fact is that it's not enough to add moisture to the air — ===you also need to keep it in. As a general rule, the recommended area for a particular humidifier to work is calculated when operating it in an isolated, unventilated room. However, living and working in a stuffy, humid room is even more dangerous to health than staying in a room that is dry but has constant fresh air. Airing the room for a few minutes negates many hours of operation of the average humidifier. The only exceptions are expensive incoming air humidification and purification systems. ## What to do When purchasing a household humidifier without a built-in microclimate control system, it is important to monitor air humidity with a hygrometer to understand its effectiveness and prevent over-humidification or excessive dryness of the air. It's also important to properly calculate the unit's power so that it is sufficient for the room where it will work. ## How to protect yourself from germs There is another serious health threat associated with humidifiers. Pathogenic microflora can build up on the membranes and filters of humidifiers. Not turning the unit on for a couple of days is sometimes enough to cause this to happen. When you turn on a microbe-contaminated humidifier, pathogens will quickly get in and out of the air and enter your respiratory tract. ## Other considerations Follow the humidifier manufacturer's recommended maintenance recommendations and do not turn it on without pre-cleaning if it has been left off for an extended period.