A hot water storage tank (also called a hot water tank, thermal storage tank, hot water thermal storage unit, heat storage tank and hot water cylinder) is a water tank used for storing hot water for future use.
A vented hot water cylinder works alongside a water tank. The water tank is used to provide the cylinder with mains fed cold water. This water is then heated and is distributed to the hot water outlets like your taps, bath, and shower as part of a gravity led system.
Tank jackets are exactly what they say they are; a form of jacket that covers the tank, also known as a jacketed vessel, like a coffee cup sleeve or a double-walled flask. They wrap around the container creating a second layer to regulate the temperature of the contents inside. In the same way, a jacketed tank is designed to keep the contents hot or cold through its ‘jacket’ enclosure.
A poorly insulated hot water tank will lose heat quickly, meaning you will have to use more energy to make more hot water. Tank jackets are an inexpensive way to increase the efficiency of your cylinder, they can be fitted easily by following the manufacturer's instructions and can help towards saving money on your heating bills.
Tank jackets are recommended for older cylinders or cylinders that don’t have their own layer of installation. Copper cylinders for example have a foam layer for installation as standard so they would not require a tank jacket.