Dual-frequency cholesteric liquid crystal (DFCLC) devices characteristically require high operation voltage, which hinders their further development in thin-film-transistor driving. Here we report on a lowervoltage switching method based on the thermodielectric effect. This technique entails applying a high-frequency voltage to occasion dielectric oscillation heating so to induce the increase in crossover frequency. The subsequent change in dielectric anisotropy of the DFCLC allows the switching, with a lower operation voltage, from the planar state to the focal conic or homeotropic state. The temperature rise incurred by the dielectric heating is described.