Heat exchanger

The utility model discloses a heat exchanger which comprises a shell, a combustion head and a spiral coil pipe, the shell comprises a first shell and a second shell which are spliced together, a smoke exhaust structure is formed on the first shell or the second shell, the spiral coil pipe is arranged in the shell, and the combustion head is arranged in the shell. An insulating heat-insulating layer is arranged between the two ends of the spiral coil pipe in the axial direction and the shell, a first partition plate is arranged in a surrounding area of the spiral coil pipe, and the surrounding area of the spiral coil pipe is divided into a first cavity and a second cavity which are distributed in the axial direction of the spiral coil pipe by the first partition plate; the first cavity is located at the end, away from the smoke exhaust structure, of the second cavity, and the combustion head is located in the first cavity. According to the utility model, the heat loss can be reduced, the sealing performance is