Syphons are used for the efficient transfer of fluids.

In plumbing systems, a syphon uses gravity to create a vacuum effect, allowing media to flow from one area to another without the need for a pump or other mechanical device.

In HVAC systems, syphons are used as part of steam traps to remove condensate from steam lines, by creating a vacuum that allows the condensate to be removed without interrupting the flow of steam.