Blown insulation comes in a loose form that is installed in attic spaces by blowing to the desired location by a machine. Rigid or board-type insulation usually comes in sheet form and is installed on the outside walls of the structure. The effectiveness of insulation is measured in R-value. R-value is the term used for describing resistance to heat flow. Thus, the higher the R-value, the greater the insulating power of the material.
All insulations can be equitably compared on an R-value basis.
The average homeowner may feel caught in the middle, not knowing which way to turn or what product to use. But don't worry. The two main insulating products in use today are fiberglass, made from melted glass, and cellulose, made from recycled newspapers. Many insulating companies install both. Fiberglass insulation is made by melting glass or sand and then spinning it into fibers, like making cotton candy.