A steam generator includes a tank for holding water, and a heating system associated with the tank for heating water in the tank to produce steam, the heating system including a gaseous fuel burner that produces hot combustion gases. A steam superheater compartment receives combustion gases from the heating system and that includes a steam line therein that receives steam from the tank to provide heat exchange between hot combustion gases traveling through the compartment and steam traveling along the steam line. A tank feed water pre-heat system that receives combustion gases from the heating system and that includes a water feed line therein to provide heat exchange between hot combustion gases and water within the water feed line, wherein the water feed line is connected for delivery of pre-heated water to a water inlet of the tank.
