Blow-in

Cellulose, often called the green choice. Manufacturers will use recycled materials (newspapers, magazines, cardboard, etc.) Then treat them with a fire retardant to make sure it won’t ignite easily.

Pros: Cellulose has a high R-value per inch, about 3.5. It is heavy, which reduces air permeation. It is cheaper than other materials

Cons: It is dusty when installing. Doesn’t look as cool as other materials. Can absorb moisture and become heavy.

Fiberglass, not so itchy anymore. It really is made of glass, just heated up and forced through tiny holes. The strands that come out are flexible and fluffy when piled up.

Pros: Very light, with decent Rvalue per inch. Doesn’t smell. Doesn’t itch anymore. Cleaner appearance. Doesn’t settle over time.

Cons: No air sealing at all, very air permeable. Can be moved around in attics if gusts of wind push through soffit. Not as cheap as other materials.