There is disclosed an inkjet printhead which comprises a plurality of nozzles (3) and one or more heater elements (10) corresponding to each nozzle (3). Each heater element is configured to heat a bubble forming liquid in the printhead to a temperature above its boiling point to form a gas bubble (12) therein. The generation of the bubble causes the ejection of a drop of an ejectable liquid (such as ink) through the respective corresponding nozzle, to effect printing. Each heater element is configured such that an actuation energy of less than 500 nanojoules (nJ) is required to be applied to that element to heat it sufficiently to form such a bubble (12) in the bubble forming liquid (which liquid can also be the ink). This configuration thus provides for a high efficiency printhead.