The invention relates to a heat device (1), in particular a hot-water bottle or a heat cushion, for bringing in at least indirect contact with a living being. The heat device comprises at least one holding chamber (2) for holding a flowable material (4), wherein the holding chamber (2) is formed by a flexible wall (6) at least in some sections, wherein the flexible wall (6) can be brought in at least indirect contact with the living being. According to the invention, a latent-heat storage means (8) is provided, wherein the latent-heat storage means is arranged in such a way that temperature control of the flowable material (4) is effected by the latent-heat storage means (8) at least at times, wherein the latent-heat storage means (8) has a phase-change material, in particular sodium acetate, wherein the phase-change material absorbs energy during an endothermic change of state as a consequence of heating and outputs energy in the form heat during an exothermic change of state.