Condensing gas water heater

The invention discloses a condensing gas water heater, which comprises a shell and a burner, a main heat exchanger and a condensing heat exchanger which are arranged in the shell. The condensing gas water heater is characterized in that: the main heat exchanger and the condensing heat exchanger are of an integrated structure and distributed in an inner-layer and outer-layer way; and a clapboard is arranged between the main heat exchanger and the condensing heat exchanger. The condensing water heater has the advantages of capability of enhancing the heat exchange function, simple and compact structure, convenience for installation and maintenance and favorable popularization value.