Insulation R-Value Calculator
Calculate insulation thickness needed and compare materials by R-value and cost.
47.9Kuses
8.2/10(387)
R-Value Needed
R-38
Thickness Needed
11.9"
R per Inch
3.2
Est. Cost
$2205
Material Comparison
| Material | R/inch | Thickness | Est. Cost |
|---|---|---|---|
| Fiberglass Batts | 3.2 | 11.9" | $2205 |
| Blown Fiberglass | 2.5 | 15.2" | $2389 |
| Cellulose (blown) | 3.5 | 10.9" | $1861 |
| Spray Foam (open) | 3.7 | 10.3" | $4402 |
| Spray Foam (closed) | 6.5 | 5.8" | $4176 |
| Rigid Foam (XPS) | 5 | 7.6" | $2606 |
| Rigid Foam (Polyiso) | 6 | 6.3" | $2533 |
| Mineral Wool | 3.3 | 11.5" | $2961 |
| Cotton Batts | 3.4 | 11.2" | $3193 |
Recommended R-Values by Climate Zone
| Zone | Attic | Wall | Floor |
|---|---|---|---|
| 1 (Hot) | R-30 | R-13 | R-13 |
| 2 (Hot) | R-38 | R-13 | R-13 |
| 3 (Warm) | R-38 | R-13 | R-19 |
| 4 (Mixed) | R-49 | R-13 | R-19 |
| 5 (Cool) | R-49 | R-20 | R-25 |
| 6 (Cold) | R-49 | R-20 | R-25 |
| 7 (Very Cold) | R-60 | R-21 | R-30 |
Insulation R-Values
R-value measures thermal resistance. Higher R-values mean better insulation. Requirements vary by climate zone and building area.
Disclaimer: This tool is provided as-is for informational and educational purposes only.