Blown fibre insulation

Blown Fibre Insulation Fiber insulation is available as loose fill or batts. Loose fill is generally fiberglass, cellulose, or rock wool that is blown into wall and attic cavities. It can provide better coverage than batts. R-values per inch for loose fill insulation are R-2.2 for fiberglass and R-3.2 for rock wool or cellulose.

A contractor using special equipment usually blows loose fill insulation into place. Some suppliers will rent you the equipment to blow the insulation into your own attic, as long as you buy the material from them.

It is not recommended to attempt blowing insulation into walls yourself. An experienced contractor is needed to avoid damage to the wall structure.
Batt insulation is easier to use for do it yourself projects. Batt insulation is available in rolls that are made to fit between the lumber in walls and ceilings. Rolled fiberglass batt insulation is sold in several different thicknesses. The R-value for fiberglass batts is about R-3.2 per inch of thickness.