Liquid heating appliance

A liquid heating appliance for heating water or other liquids or steam and which comprises:

• a primary heat storage chamber or body that is thermally insulated and which in use contains or comprises a heat storing liquid or solid;
• and a secondary chamber adjacent the primary heat storage chamber or body through which a liquid or steam to be heated is passed in use, the appliance having a heat transfer feature to selectively transfer thermal energy from the heat storing liquid or solid of the primary heat storage chamber or body to the liquid or steam to be heated in the secondary chamber, wherein the secondary chamber is a conduit through which the liquid to be heated is able to flow and wherein the primary heat storage chamber is thermally insulated and shielded by a thermal barrier from conductive direct heat transfer relationship with the secondary chamber and the thermal barrier comprises a vacuum gap chamber, and wherein the heat transfer feature comprises a mechanism that moves a surface on the primary heat chamber or body and a surface on the secondary chamber relative to each other to move together to be contacting or in intimate proximity with each other for thermal energy transfer or to move apart.