Moisture absorption, ranging from 5 to 20 percent of its weight, is one disadvantage of cellulose insulation. This also may alter its physical and chemical properties, as well as settle, if the insulation is not applied at the correct density. Other concerns with loose-fill fiber insulation are displacement as a result of wind and infesta­tions of rodents. It is also possible that, over many decades, dust and dirt accumulation could reduce the R-value, either by com­pressing the insulation or by filling air pockets.