Mains pressure storage hot water

These are available in electric or natural gas models. They store hot water in an insulated cylinder ready for immediate use. The thermostat keeps the water at a set temperature — when you use hot water, it is drawn out of the tank and replaced with cold water. The change in temperature activates the element or burner, which reheats the water to the temperature set by the thermostat.

Natural gas hot water systems have an Australian Gas Association (AGA) star rating — the more stars, the more energy efficient it is.