A method indicates to a user the fuel consumption and/or efficiency of a heating installation having a heat pump with a thermal compressor, a heating fluid distribution circuit and radiators receiving a first quantity of energy Q1. The method includes the steps: A—of determining, over a predetermined time period a second quantity of energy Q2, corresponding to the supply of heat energy used to drive the compressor, B—of determining, over the same predetermined time period, a third quantity of energy Q3 corresponding to free energy taken from the external environment, C—of displaying the quantities Q2 and Q3, in relation to the predetermined time period, on a display screen and/or in a document for invoicing the customer.