Abstract: A water heater including a tank to hold water to be heated, the tank having an outer surface, and a source of heat for heating the water in the tank. The water heater further includes a jacket surrounding the tank, the jacket having an inner surface facing the tank, a plastic skin attached to the outer surface of the tank, and an annular space between the tank and the jacket. In addition, the water heater includes foam insulation within the annular space. The foam insulation cures to form a porous solid layer of insulation between the tank and jacket, and the foam insulation shrinks during curing. The foam insulation adheres to the inner surface of the jacket, and the foam insulation does not adhere to the plastic skin during curing, to thereby reduce a deforming load on a portion of the jacket opposite the plastic skin.

Abstract: A water heater including a tank, a cylindrical jacket surrounding the tank to provide an insulating space therebetween and a cover member mounted on top of the jacket to close off the top of the insulating space. An insulating wall is provided in the insulating space between the tank and the jacket. The insulating wall is comprised of a plastic envelope member and a wall of insulating material which has been foamed-in-place inside the envelope member. The envelope is constructed in such a way as to evenly distribute the foam material inside the envelope during the foamed-in-place operation.