There are many reasons why a greenhouse humidifier is a maintenance free system and can last for many years of great use. One of the reasons is the air pressure going through the system. Nozzle systems use 1000 psi of pressure where fogger systems only use 110 psi. This allow for much less wear and tear on the lines. These systems can run day and night with little maintenance because of the gentle use the system has. The only normal maintenance is making sure to completely flush out any chemical or fertilizers that were running through the system to make sure the line is clean.