Calculate insulation needs and energy savings
An insulation calculator determines material needs based on area, current R-value, and target R-value. Proper insulation reduces energy costs and improves comfort.
Insulation = Area × (Target R-Value - Current R-Value) / Material R-Value per Inch
Varies by location. Attic: R-38 to R-60. Walls: R-13 to R-21. Floors: R-25 to R-30. Check ENERGY STAR recommendations for your climate zone. Higher R-value = better insulation.
Fiberglass batts: Affordable, DIY-friendly. Blown-in: Great for attics, fills gaps. Spray foam: Best air seal, highest R-value per inch. Rigid foam: For basements and exterior walls.
Attic insulation: 10-50% heating/cooling savings. Wall insulation: 15-25% savings. Payback period: 2-5 years typically. Actual savings depend on climate, current insulation, and energy costs.
Yes, if existing insulation is dry and not damaged. Don't add vapor barrier over existing insulation. Unfaced batts or blown-in work best. Check for mold or moisture issues first.
Depends on material and target R-value. Fiberglass batts: ~3.5" for R-13, ~9.5" for R-30. Spray foam: ~3" for R-20. Blown-in fiberglass: ~14" for R-38. Don't compress insulation.
Cold climates: Vapor barrier on warm side (interior). Hot/humid climates: Vapor barrier on exterior or skip it. Mixed climates: Check local codes. Use faced insulation or separate poly sheeting.