Hot water cylinders are large hot water storage tanks used for storing hot water for domestic or commercial use. They are commonly used to ensure ample amounts of hot water is readily available for showering, bathing and for general household use.
There are two main types of cylinders - unvented and vented. This is then broken down into direct and indirect cylinders. Which cylinder you need all depends on the hot water system you have and depending on how much stored hot water you intend to use day to day, will determine what hot water cylinder size you need.