A water heating system includes a burner assembly for providing a source of thermal energy to a heat exchanger. A water inlet conduit is coupled to the heat exchanger assembly for supplying fresh water to be heated, and a water exit conduit is coupled to the heat exchanger assembly for delivering the heated water to a point of use. A bypass conduit connects the water exit conduit to the water inlet conduit, and a pump disposed in the bypass conduit circulates at least a portion of the heated water from the water exit conduit to the water inlet conduit. A feed-forward sensor positioned in the water inlet conduit between the heat exchanger assembly and the bypass conduit monitors a parameter of the water entering the heat exchanger assembly, and a processor controls the operation of the of the burner assembly in response to the feed-forward sensor.