Cellulose Or Fiberglass In Attic

Or 7 inches of cellulose.

Cellulose or fiberglass in attic.

Cellulose has 38 better air infiltration than fiberglass. Compared to fiberglass cellulose is a superb air blocker. Blown cellulose is typically the preferred choice of insulation for attics. As the temperature difference between the living space and attic increases the r value of blown fiberglass diminishes.

Cellulose forms a dense continuous mat of insulation in your 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. Costs slightly more than fiberglass. Downsides of cellulose insulation.

Loose fill cellulose insulation can settle around and conform to most of the obstructions found in walls and attics. Cellulose can be blown into existing walls through small access hoses without dismantling the entire wall as with fiberglass batts. 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. This is called wind washing.

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. Unless you opt for spray foam then the insulation choices normally come down to cellulose and fibreglass. Fiberglass insulation is the easiest insulation product on the market to install and if installed correctly the most effective product on the market for home attic insulation. So what are the advantages and disadvantages of each of these.

Fiberglass batts however are less expensive costing on average 0 30 to 0 40 a square foot for 6 inches of insulation. When walls are already finished injecting loose fill cellulose insulation is one of the few ways of adding. Cellulose in walls and the attic also has some soundproofing properties that reduce noise transmission through the house. Air moving through a vented attic deposits dirt and dust into fiberglass batts.

Loose fill blown fiberglass insulation has another slight problem. Rather than trying to meticulously lay fiberglass insulation over the attic homeowners and builders can simply blow cellulose insulation throughout the attic. This keeps the air from moving within the insulation and from penetrations between the air conditioned space and the attic. Since cellulose is blown in it fills all the gaps crevices nooks and crannies in your attic unlike batts that can leave gaps.

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. Cellulose is more difficult to cheat than fiberglass.