A hot water heating system is provided for heating water that is utilized to heat a structure such as a tobacco barn. The hot water heating system includes a base and a vessel, movably mounted on the base, for holding water supported on the base. The vessel is movable back and forth on the base between a heating position and a loading position. In the heating position, the vessel overlies a fire chamber. When the vessel moves to the loading position, the fire chamber is open at the top so as to permit solid fuel, such as wood, to be loaded through the open top of the fire chamber.