Blown-In Cellulose Insulation
Cellulose insulation is manufactured from recycled newspaper and cardboard treated with borate compounds for fire resistance and pest deterrence. It is installed using a blowing machine, which can be rented from most home improvement stores for DIY attic applications. Cellulose offers a higher R-value per inch than fiberglass blown-in and is one of the most cost-effective insulation materials available. Its density and fiber structure provide good air-sealing properties compared to fiberglass, reducing infiltration heat loss. Dense-pack cellulose in walls achieves approximately R-3.5 per inch and significantly reduces air leakage through the wall assembly. The borate treatment makes cellulose resistant to mold, insects, and rodents.
Blown-In Cellulose Specifications
Best Applications for Blown-In Cellulose
Blown-In Cellulose is recommended for the following building components. Each application link shows the specific R-value requirements by climate zone and how Blown-In Cellulose compares against other insulation options for that component.
Thickness Required by Climate Zone
The table below shows the thickness of Blown-In Cellulose needed to achieve the DOE recommended R-value for each building component in every climate zone. Cells showing "N/R" indicate that insulation is not required for that component in that zone. Use this table to quickly determine how much Blown-In Cellulose you need for your specific zone and application.
| Zone | Attic | Wall Cavity | Wall Cont. | Floor | Basement | Crawlspace | Cathedral | Garage |
|---|---|---|---|---|---|---|---|---|
| Zone 1 | 8.6" | 3.7" | N/R | 3.7" | N/R | N/R | 6.3" | 5.4" |
| Zone 2 | 10.9" | 3.7" | N/R | 3.7" | N/R | N/R | 6.3" | 5.4" |
| Zone 3 | 10.9" | 3.7" | N/R | 5.4" | 1.4" | 1.4" | 8.6" | 5.4" |
| Zone 4 | 14" | 3.7" | 1.4" | 7.1" | 2.9" | 2.9" | 10.9" | 8.6" |
| Zone 5 | 14" | 3.7" | 1.4" | 7.1" | 2.9" | 2.9" | 10.9" | 8.6" |
| Zone 6 | 17.1" | 3.7" | 2.9" | 7.1" | 4.3" | 2.9" | 14" | 10.9" |
| Zone 7 | 17.1" | 3.7" | 2.9" | 7.1" | 4.3" | 2.9" | 14" | 10.9" |
| Zone 8 | 17.1" | 3.7" | 4.3" | 7.1" | 5.4" | 2.9" | 14" | 10.9" |
Cost Estimates by Climate Zone (per 1,000 sq ft)
Material cost estimates for Blown-In Cellulose at the DOE recommended R-value for each climate zone and component. These are material costs only and do not include labor. Professional installation typically adds 30-50% to the material cost shown below.
| Zone | Attic | Wall Cavity | Wall Cont. | Floor | Basement |
|---|---|---|---|---|---|
| Zone 1 | $2,100 | $910 | N/R | $910 | N/R |
| Zone 2 | $2,660 | $910 | N/R | $910 | N/R |
| Zone 3 | $2,660 | $910 | N/R | $1,330 | $350 |
| Zone 4 | $3,430 | $910 | $350 | $1,750 | $700 |
| Zone 5 | $3,430 | $910 | $350 | $1,750 | $700 |
| Zone 6 | $4,200 | $910 | $700 | $1,750 | $1,050 |
| Zone 7 | $4,200 | $910 | $700 | $1,750 | $1,050 |
| Zone 8 | $4,200 | $910 | $1,050 | $1,750 | $1,330 |
Advantages and Limitations
Every insulation type has trade-offs that affect its suitability for different applications. Understanding these trade-offs helps you select the right insulation for your specific project requirements, budget, and installation constraints.
Advantages of Blown-In Cellulose
- Low material cost makes it budget-friendly for large areas
- Suitable for DIY installation, reducing labor costs
- Well-suited for: Attic, Wall Cavity
Limitations of Blown-In Cellulose
Compare Other Insulation Types
Browse specifications and cost analysis for other insulation materials to find the best option for your project.