Blown-In Attic Insulation Bag & R-Value Calculator
Calculate loose-fill blown-in fiberglass and cellulose insulation bag counts, initial install thickness, and settled depth to reach target thermal resistance (R-30 to R-60) per DOE Climate Zones and IECC 2021/2024.
Attic Dimensions & Target R-Value
Feet
Feet
Inches
Enter 0 if attic is bare or cleared.
$
USD
Total Insulation Required
IECC ZONE 4-7 COMPLIANT
29 Bags
Total 725 lbs cellulose (~$536.50 material cost)
Initial Install Depth
16.0 in
Settles to 13.2 in (20% settling)
Total Thermal Resistance
R-49
Adding R-49 new insulation
Coverage & Application Summary
Net Attic Floor Area:
1,200 sq ft
Blower Machine Rental:
Free with 20+ bags purchase at most home centers
Rafter Air Baffles (Raftervents):
~30 Baffles required at soffits