Two different methods for deriving the energy-balance equation for hot electrons in semiconductors are described in the literature. The first method uses the Boltzmann equation, while in the second method the equation is obtained from the rates of scattering out of a state by absorption and emission processes. It is shown that for the general case of intervalley and intersubband scattering in semiconductors the use of method 2 is incorrect, and only in a special case the two methods are identical. It is pointed out that in method 2 the rate of change of energy due to intervalley exchange of electrons is neglected. Because of this, the two methods should give different expressions and different values of transport coefficients. The nature of this difference is discussed from the general point of view, and illustrated in the case of bulk and of quantized inversion layer by assuming a Maxwellian distribution. © 1979 The American Physical Society.