The document discusses conventional gas-fired water heaters. It notes that they typically include a tank to hold water, a combustion chamber below or within the tank, a burner within the combustion chamber, and thermal insulation. When the water temperature drops, gas flows to the burner where it is ignited to heat the water. The products of combustion are vented through a flue. However, these designs are not optimal for efficiency and manufacturing costs. The document seeks to describe an improved water heater design with a unified combustion chamber and burner construction that has lower manufacturing costs and better operating characteristics.