Cellulose Or Fiberglass In Attic

Or 7 inches of cellulose.

Cellulose or fiberglass in attic.

Once it has settled fiberglass has an r value of 2 1 2 7 per inch while cellulose has an r value of approximately 3 0 per inch. Since cellulose is blown in it fills all the gaps crevices nooks and crannies in your attic unlike batts that can leave gaps. You can get to the same place with either material. 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.

Fiberglass batts however are less expensive costing on average 0 30 to 0 40 a square foot for 6 inches of insulation. This keeps the air from moving within the insulation and from penetrations between the air conditioned space and the attic. So what are the advantages and disadvantages of each of these. Air moving through a vented attic deposits dirt and dust into fiberglass batts.

This is called wind washing. Rather than trying to meticulously lay fiberglass insulation over the attic homeowners and builders can simply blow cellulose insulation throughout the attic. Cellulose is more difficult to cheat than fiberglass. When walls are already finished injecting loose fill cellulose insulation is one of the few ways of adding.

As the temperature difference between the living space and attic increases the r value of blown fiberglass diminishes. Unless you opt for spray foam then the insulation choices normally come down to cellulose and fibreglass. Downsides of cellulose insulation. When using cellulose blown in dry insulation it requires a machine to achieve its purpose and a training session from wherever you rent the blower from.

The two main least expensive and most commonly used residential insulation materials is cellulose and fibreglass. Loose fill blown fiberglass insulation has another slight problem. Cellulose has 38 better air infiltration than fiberglass. Compared to fiberglass cellulose is a superb air blocker.

Cellulose forms a dense continuous mat of insulation in your attic. Cellulose can be blown into existing walls through small access hoses without dismantling the entire wall as with fiberglass batts. Cellulose in walls and the attic also has some soundproofing properties that reduce noise transmission through the house. Loose fill cellulose insulation can settle around and conform to most of the obstructions found in walls and attics.

Loose fill cellulose is relatively inexpensive yet still has an r value of about 3 5 per inch of thickness compared to fiberglass r value between r3 to r4 per inch. Blown cellulose is typically the preferred choice of insulation for attics.