Insulation Calculator
Estimate insulation materials and R-value for your project
Length of area to insulate
Width of area to insulate
Select material
Check local code
Total Area
—
sq ft
Insulation Thickness
—
inches
Batts/Rolls Needed
—
pieces
Estimated Cost
—
USD
Disclaimer: Results are estimates based on standard formulas. Not a substitute for professional advice from a licensed contractor, engineer, or architect. Verify all calculations before making purchasing or construction decisions.
How to Use This Calculator
Proper insulation reduces energy bills by 10-50%. Our calculator helps determine R-value and material quantities.
- Determine climate zone and target R-value
- Measure length and width
- Choose insulation type
- Enter specifications
- Consider air sealing first
Expert Insights
Smart analysis for your Insulation project
R-Value by Climate Zone
Attic: R-30 to R-60 depending on zone. Walls: R-13 to R-20+. AI maps your region to DOE climate zone recommendations.
Air Sealing Impact
Air sealing before insulating improves efficiency 20-40%. AI calculates the combined R-value benefit of sealing + insulating.
Batt vs Blown-In vs Spray Foam
Batts: lowest cost, DIY-friendly. Blown-in: better coverage. Spray foam: air seals + insulates. AI compares cost per R-value for each.
Calculation Formula
Thickness = Target R / R per inch
Batts = Area / Batt coverage (40 sq ft/batt)
Authority References
Our calculations are based on guidelines and standards from these authoritative sources:
- U.S. Department of Energy (DOE) — Insulation R-Value Recommendations by Climate Zone. Learn more
- ENERGY STAR — Recommended Home Insulation R-Values. Learn more
- International Energy Conservation Code (IECC) — Climate Zone Insulation Requirements. Learn more
Frequently Asked Questions
What R-value do I need for my attic?
R-38 to R-49 for most US climate zones (Zones 4-8). Southern zones (1-3): R-30 to R-38.
How much does attic insulation cost?
DIY fiberglass batts: $0.30-$1.50/sq ft. Professional blown-in: $1.00-$2.50/sq ft.
Can I add new insulation over old?
Yes. Use unfaced batts or blown-in over existing. Do not compress old insulation.