Attic Insulation Cellulose Vs Fiberglass Blown In

Cellulose is more difficult to cheat than fiberglass.

Attic insulation cellulose vs fiberglass blown in.

Cellulose has 38 better air infiltration than fiberglass. Fiberglass batts however are less expensive costing on average 0 30 to 0 40 a square foot for 6 inches of insulation. 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. Another major weakness of fiberglass insulation which does nothing to stop air from passing through it.

Cellulose forms a dense continuous mat of insulation in your attic. 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. Installation costs for blown in insulation costs around 2 a square foot where installation costs for batts is around 1 a square foot. With that said most homeowners agree that blown cellulose is slightly more efficient due to the face that it blocks more air than fiberglass.

One key insulation difference is that cellulose settles over time potentially leaving some areas in walls particularly with little or no insulation. As the temperature difference between the living space and attic increases the r value of blown fiberglass diminishes. Another important benefit from dense packed cellulose is its ability to limit air movement which cuts down on heat loss through convection. You ve probably got batts in your attic walls and crawlspace right now.

This keeps the air from moving within the insulation and from penetrations between the air conditioned space and the attic. Fiberglass is by far the most common type of insulation sold in batt form although cellulose batts do exist. Fiberglass manufacturers have developed blown fiberglass insulation they claim won t settle over time. Unlike fiberglass batts with paper backing it doesn t burn as you might expect ground up paper to.

Despite competing industries stating otherwise independent testing confirms that cellulose is safe and approved in all building codes. 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. 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. You can find high r value insulation produced in both fiberglass and blown cellulose.

Very common very problematic. In fact many professionals consider cellulose to be more fire safe than fiberglass. The higher the r value the more efficient it is. The two main least expensive and most commonly used residential insulation materials is cellulose and fibreglass.