Vacuum Tube Technology: Each tube consists of two layers of borosilicate glass with a vacuum in between that acts as an insulator, retaining up to 97% of the captured thermal energy.Passive Circulation (Thermosiphon): As the sun heats the water inside the tubes, it becomes less dense and rises into the storage tank, while colder, denser water sinks down into the tubes to be heated.Gravity Flow: Because it is a non-pressurized system, it relies on gravity to deliver hot water to your taps, making it ideal for single-story homes with simple plumbing.