Heater

The utility model provides a heater. The heater comprises a steam-water mixing cavity for mixing steam and pre-heating cold water, wherein the steam-water mixing cavity is provided with a cold water input pipeline and a hot water output pipeline respectively; the steam-water mixing cavity is further provided with a steam input pipeline for inputting steam. According to the heater, the steam and the cold water are mixed and a whole heating process is carried out in the steam-water mixing cavity; in the process of mixing and heating the steam and the coldwater, any heating interval is not generated in the process, so that the heat efficiency of heating work for mixing the steam and the cold water is high and the heat transmission speed is rapid. Meanwhile, the heating work is carried out in the steam-water mixing cavity and condensed water generated by the steam can be directly used, so that the utilization of water is saved and a condition of discharging the condensed water out is avoided.