Attic Insulation Cellulose Vs Fiberglass Blown In

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.

Attic insulation cellulose vs fiberglass blown in.

The r value of fiberglass insulation is approximately 2 2 per inch so you need much thicker insulation to achieve the same r value of 38. The higher the r value the more efficient it is. Unlike fiberglass batts with paper backing it doesn t burn as you might expect ground up paper to. One key insulation difference is that cellulose settles over time potentially leaving some areas in walls particularly with little or no insulation.

Another major weakness of fiberglass insulation which does nothing to stop air from passing through it. 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. Cellulose forms a dense continuous mat of insulation in your attic.

Unless you opt for spray foam then the insulation choices normally come down to cellulose and fibreglass. You can find high r value insulation produced in both fiberglass and blown cellulose. The two main least expensive and most commonly used residential insulation materials is cellulose and fibreglass. It comes in rolls and has paper backing on one side.

Loose fill blown fiberglass insulation has another slight problem. In fact many professionals consider cellulose to be more fire safe than fiberglass. Cellulose has 38 better air infiltration than fiberglass. Fiberglass is by far the most common type of insulation sold in batt form although cellulose batts do exist.

The r value of cellulose insulation is approximately 3 8 per inch so you need about insulation that is about 10 inches thick to reach r 38. Very common very problematic. With that said most homeowners agree that blown cellulose is slightly more efficient due to the face that it blocks more air than fiberglass. Fiberglass manufacturers have developed blown fiberglass insulation they claim won t settle over time.

You ve probably got batts in your attic walls and crawlspace right now. Another important benefit from dense packed cellulose is its ability to limit air movement which cuts down on heat loss through convection. Fiberglass batts however are less expensive costing on average 0 30 to 0 40 a square foot for 6 inches of insulation. Despite competing industries stating otherwise independent testing confirms that cellulose is safe and approved in all building codes.