  In this brief report, following the recent developments on formulating a
quantum analogue of the classical energy equipartition theorem for open systems
where the heat bath comprises of independent oscillators, i.e. bosonic degrees
of freedom, we present an analogous result for fermionic systems. The most
general case where the system is connected to multiple reservoirs is considered
and the mean energy in the steady state is expressed as an integral over the
reservoir frequencies. Physically this would correspond to summing over the
contributions of the bath degrees of freedom to the mean energy of the system
over a suitable distribution function $\rho(\omega)$ dependent on the system
parameters. This result holds for nonequilibrium steady states, even in the
nonlinear regime far from equilibrium. We also analyze the zero temperature
behaviour and low temperature corrections to the mean energy of the system.
