Unless you opt for spray foam then the insulation choices normally come down to cellulose and fibreglass.
Fiberglass insulation vs cellulose insulation for attic.
Thus creating a more energy efficient home.
Cellulose insulation is also chemically treated to resist fire insects and mold.
Cellulose insulation is considered green as it is made from recycled newspaper and requires less energy to manufacture than fiberglass insulation.
Dirty fiberglass batts have a significantly reduced r value.
You can get to the same place with either material.
Because it is denser than fiberglass cellulose is much more resistant to wind washing.
Fiberglass is a suspected carcinogen.
It has a better resistance to air flow and prevents the upward movement of air caused by temperature differences.
Assuming your current attic insulation is made from fiberglass and has a value of r 13 you d have to add roughly 10 inches of additional fiberglass to hit r 38.
The two main least expensive and most commonly used residential insulation materials is cellulose and fibreglass.
Air moving through a vented attic deposits dirt and dust into fiberglass batts.
Or 7 inches of cellulose.
Many fiberglass installers fluff the fiber with extra air so you don t get as much insulation as you re supposed to.
This is called wind washing.