A method of reducing the amount of cooling energy required to heat and cool a building is provided. The method includes disposing a porous insulating material in the exterior walls and substantially covering the ceiling in the attic space of the building to a substantial depth. The porous insulating material includes a desiccant. The method further includes permitting the desiccant - bearing porous insulating material to adsorb water moisture from the attic space and then permitting the adsorbed water moisture to desorb from the desiccant - bearing porous insulating material into the enclosed room of the building, resulting in a reduction in the amount of energy required to heat and cool the building.