Cellulose Or Fiberglass In Attic

Air moving through a vented attic deposits dirt and dust into fiberglass batts.

Cellulose or fiberglass in attic.

Cellulose can be blown into existing walls through small access hoses without dismantling the entire wall as with fiberglass batts. Rather than trying to meticulously lay fiberglass insulation over the attic homeowners and builders can simply blow cellulose insulation throughout the attic. 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. Downsides of cellulose insulation.

You can get to the same place with either material. Blown cellulose is typically the preferred choice of insulation for attics. Loose fill cellulose insulation can settle around and conform to most of the obstructions found in walls and attics. So what are the advantages and disadvantages of each of these.

Compared to fiberglass cellulose is a superb air blocker. Cellulose is more difficult to cheat than fiberglass. This is called wind washing. When walls are already finished injecting loose fill cellulose insulation is one of the few ways of adding.

Fiberglass batts however are less expensive costing on average 0 30 to 0 40 a square foot for 6 inches of insulation. 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. Cellulose has 38 better air infiltration than fiberglass. As the temperature difference between the living space and attic increases the r value of blown fiberglass diminishes.

When comparing blown in insulation both fiberglass and cellulose are nearly identical in price both costing around 0 70 to 0 80 per square foot for 6 inches of insulation. Since cellulose is blown in it fills all the gaps crevices nooks and crannies in your attic unlike batts that can leave gaps. Costs slightly more than fiberglass. 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.

This keeps the air from moving within the insulation and from penetrations between the air conditioned space and the attic. Loose fill blown fiberglass insulation has another slight problem. Or 7 inches of cellulose. Cellulose forms a dense continuous mat of insulation in your attic.

Cellulose in walls and the attic also has some soundproofing properties that reduce noise transmission through the house. 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.