Air moving through a vented attic deposits dirt and dust into fiberglass batts.
Cellulose or fiberglass in attic.
Since cellulose is blown in it fills all the gaps crevices nooks and crannies in your attic unlike batts that can leave gaps.
So what are the advantages and disadvantages of each of these.
Unless you opt for spray foam then the insulation choices normally come down to cellulose and fibreglass.
Compared to fiberglass cellulose is a superb air blocker.
You can get to the same place with either material.
When walls are already finished injecting loose fill cellulose insulation is one of the few ways of adding.
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.
Or 7 inches of cellulose.
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.
Loose fill blown fiberglass insulation has another slight problem.
Loose fill cellulose insulation can settle around and conform to most of the obstructions found in walls and attics.
Costs slightly more than fiberglass.
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.
Cellulose forms a dense continuous mat of insulation in your attic.
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 can be blown into existing walls through small access hoses without dismantling the entire wall as with fiberglass batts.
This keeps the air from moving within the insulation and from penetrations between the air conditioned space and the attic.
This is called wind washing.
Fiberglass batts however are less expensive costing on average 0 30 to 0 40 a square foot for 6 inches of insulation.
Cellulose in walls and the attic also has some soundproofing properties that reduce noise transmission through the house.
The two main least expensive and most commonly used residential insulation materials is cellulose and fibreglass.
Cellulose has 38 better air infiltration than fiberglass.
Cellulose is more difficult to cheat than fiberglass.
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.