What does steam to steam humidifier mean?

Answer

A steam to steam humidifier uses steam, typically generated by a boiler located in the building, to heat water for creating steam to use for humidification. The most common reason for doing this is that boiler steam usually contains water treatment chemicals that people do not want to breathe. Domestic, or Potable water, is often used as the water supply for the humidification steam. Reverse Osmosis or Deionized Water streams may also be used for humidification, if available, if dust particles are a concern.