By heating water only as it passes through the unit, this water heater is very energy efficient & saves you money! It has a continuous system & an electric ignition. The LPG Rinnai hot water instantaneous/continuous systems work by heating water as it passes through the unit so you only use energy when you turn the tap on. This process makes the Rinnai hot water systems extremely energy efficient systems, by only heating water when required. In turn, it reduces your running costs, as well as greenhouse gas emissions. The compact Rinnai B26 will continuously supply hot water to one-two bathroom homes. It's also the most energy efficient 26L continuous flow system on the market.