I recently purchased a large, 3-story, Victorian Lady in PA that is NOT very cost efficient for heating. From what I can tell there is no insullation in the walls, all still the original plaster, nor in the attic, which also still retains it's original plaster. My question is: What would be the most efficient way of insullating the house without destroying the plaster? Is there a danger of moisture accumulation if I use batting in the eaves behind the attic rooms?