  The efficiency of nonmodal self-heating by acoustic wave perturbations is
examined. Considering different kinds of kinematically complex velocity
patterns we show that nonmodal instabilities arising in these inhomogeneous
flows may lead to significant amplification of acoustic waves. Subsequently,
the presence of viscous dissipation damps these amplified waves and causes the
energy transfer back to the background flow in the form of heat; viz. closes
the "self-heating" cycle and contributes to the net heating of the flow
patterns and the chromospheric network as a whole. The acoustic self-heating
depends only on the presence of kinematically complex flows and dissipation. It
is argued that together with other mechanisms of nonlinear nature the
self-heating \textit{may be} a probable additinal mechanism of nonmagnetic
chromospheric heating in the Sun and other solar-type stars with slow rotation
and extended convective regions.
