Insulation R-Values
R-Value measures resistance to heat flow. The higher the number, the better the insulation.
Zone Requirements (DOE)
| Climate Zone | Uninsulated Attic | Floor | Wall |
|---|---|---|---|
| Zones 1-2 (Hot) | R-30 to R-49 | R-13 | R-13 to R-15 |
| Zones 3-4 (Mixed) | R-38 to R-60 | R-19 to R-25 | R-20 |
| Zones 5-8 (Cold) | R-49 to R-60 | R-25 to R-30 | R-20 to R-30 |
Materials
- Fiberglass Batt: R-3.1 to R-3.4 per inch. Cheap, but hard to seal air gaps.
- Blown-in Cellulose: R-3.2 to R-3.8 per inch. Excellent for attics.
- Closed-Cell Spray Foam: R-6.0 to R-6.5 per inch. High cost, acts as a vapor barrier and structural support.