Blown-In Cellulose in Zone 8 (Subarctic)
Blown-In Cellulose provides R-3.5 per inch of thickness at a material cost of $0.07 per square foot per R-value point. In Climate Zone 8 (Subarctic), with 14,000 HDD and 100 CDD, see the thickness and cost required for each building component below.
Specifications
Blown-In Cellulose Requirements by Component in Zone 8
The table below shows the DOE recommended R-value, required thickness of Blown-In Cellulose, material cost per square foot, and total material cost per 1,000 square feet for each building component in Climate Zone 8. Components where Blown-In Cellulose is specifically recommended are highlighted. Components where insulation is not required show "N/R" (not required).
| Component | Required R | Thickness | $/SqFt | $/1000 SqFt | Fits Cavity | Rec. |
|---|---|---|---|---|---|---|
| Attic | R-60 | 17.1" | $4.20 | $4,200 | No | Yes |
| Wall Cavity | R-13 | 3.7" | $0.91 | $910 | No | Yes |
| Wall Continuous (Exterior) | R-15 | 4.3" | $1.05 | $1,050 | No | - |
| Floor (Over Unconditioned Space) | R-25 | 7.1" | $1.75 | $1,750 | Yes | - |
| Basement Wall | R-19 | 5.4" | $1.33 | $1,330 | No | - |
| Crawlspace | R-10 | 2.9" | $0.70 | $700 | Yes | - |
| Cathedral Ceiling | R-49 | 14" | $3.43 | $3,430 | No | - |
| Garage Ceiling (Below Living Space) | R-38 | 10.9" | $2.66 | $2,660 | No | - |
Blown-In Cellulose in Zone 8 — Guidance
Blown-in cellulose at R-3.5 per inch is one of the most cost-effective insulation options for Zone 8 (Subarctic). In this cold climate zone, cellulose is the workhorse insulation for attic applications where deep depths are needed to achieve R-60. At $0.07 per square foot per R-value, cellulose is the least expensive way to achieve high R-values in open attic spaces. The dense fiber structure of cellulose provides better air sealing than fiberglass, reducing infiltration heat loss through the attic floor. For wall retrofits, dense-pack cellulose installed through small access holes fills the cavity completely and dramatically reduces air leakage — studies show dense-pack cellulose reduces wall air leakage by 70 to 80 percent. The borate treatment in cellulose provides resistance to mold, insects, and rodents, making it suitable for both attic and wall applications. Cellulose is also one of the most environmentally sustainable insulation products available, with over 80 percent recycled content.
States in Zone 8
These states include areas within Climate Zone 8 where the Blown-In Cellulose requirements shown above apply. Click any state for its complete insulation recommendations.