A gas heater (1) and gas heater method heat a carrier gas flow. The gas heater includes a gas inlet (2) a gas outlet (3) and a connecting gas channel (4). A heating system (5), arranged in the gas channel, includes a heat exchanger (12) surface. The carrier gas at least partly flows over the surface to heat the carrier gas flow. The gas channel includes a first section (6), arranged upstream of the heat exchanger in a flow direction, and a second section (7) arranged downstream of the heat exchanger. A respective sensor (8a, 8b), for detecting a pressure value, is in the first and the second section or directly adjacent thereto. Pressure values are transmitted to a control and analysis unit (9) which ascertains a mass and/or volume flow of the carrier gas in the gas channel based on a pressure difference between the two pressure values.
