Extruded Polystyrene (XPS) in Zone 7 (Very Cold)
Extruded Polystyrene (XPS) provides R-5 per inch of thickness at a material cost of $0.18 per square foot per R-value point. In Climate Zone 7 (Very Cold), with 10,000 HDD and 300 CDD, see the thickness and cost required for each building component below.
Specifications
Extruded Polystyrene (XPS) Requirements by Component in Zone 7
The table below shows the DOE recommended R-value, required thickness of Extruded Polystyrene (XPS), material cost per square foot, and total material cost per 1,000 square feet for each building component in Climate Zone 7. Components where Extruded Polystyrene (XPS) 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 | 12" | $10.80 | $10,800 | Yes | - |
| Wall Cavity | R-13 | 2.6" | $2.34 | $2,340 | Yes | - |
| Wall Continuous (Exterior) | R-10 | 2" | $1.80 | $1,800 | Yes | Yes |
| Floor (Over Unconditioned Space) | R-25 | 5" | $4.50 | $4,500 | Yes | Yes |
| Basement Wall | R-15 | 3" | $2.70 | $2,700 | Yes | Yes |
| Crawlspace | R-10 | 2" | $1.80 | $1,800 | Yes | Yes |
| Cathedral Ceiling | R-49 | 9.8" | $8.82 | $8,820 | No | - |
| Garage Ceiling (Below Living Space) | R-38 | 7.6" | $6.84 | $6,840 | Yes | - |
Extruded Polystyrene (XPS) in Zone 7 — Guidance
Extruded Polystyrene (XPS) at R-5 per inch provides excellent thermal performance in a thin profile, making it ideal for applications where space is limited. In Climate Zone 7 (Very Cold), the high R-value requirements mean that the choice of insulation type significantly affects both the required thickness and the total project cost. This product is suitable for DIY installation, which can reduce total project costs by 30 to 50 percent compared to professional installation. The excellent moisture resistance of Extruded Polystyrene (XPS) makes it suitable for below-grade and moisture-prone applications in Zone 7. For the specific R-value requirements in Zone 7, review the component comparison table above to see the thickness and cost for each building component.
States in Zone 7
These states include areas within Climate Zone 7 where the Extruded Polystyrene (XPS) requirements shown above apply. Click any state for its complete insulation recommendations.