A UV-C unit is the least expensive way to safeguard against the Legionella bacteria. The unit emits very short-wave ultraviolet light. This electromagnetic radiation kills and disables bacteria and viruses by damaging their DNA. However the dead bacteria, along with any minerals present, will remain in the water and are not removed by the unit. It is an effective way to kill the existing bacteria but it is essential that no new bacterial contamination be introduced further along in the water supply. Further, the UV-C unit should be checked regularly and preferably will have a sensor indicating when the lamp should be changed.
The advantages of UV-C units in humidifiers: