What R-value insulation do I need?

Required R-values depend on your climate zone and location in the home. Attics need R-38 to R-60, exterior walls R-13 to R-21, and floors R-25 to R-30 in most US climate zones. Our calculator recommends the appropriate R-value based on your ZIP code and building location.

How much does insulation cost per square foot?

Fiberglass batt insulation costs $0.50-$1.50/sq ft installed, blown-in cellulose $1-$2/sq ft, spray foam open-cell $1-$2/sq ft, and spray foam closed-cell $2-$4/sq ft. Higher R-values and premium materials cost more but provide better energy efficiency.

Is spray foam insulation worth the extra cost?

Spray foam costs 2-3x more than fiberglass but provides superior air sealing, higher R-value per inch, and moisture resistance. It typically pays back through energy savings in 5-7 years in cold climates. It is especially valuable in crawl spaces, rim joists, and cathedral ceilings.

Can I install insulation myself?

Fiberglass batts and blown-in insulation are DIY-friendly for attics and open walls. Spray foam requires professional equipment and training. Always wear protective gear (respirator, gloves, long sleeves) when handling insulation. Our calculator shows DIY vs. professional costs.

Insulation Calculator

Calculate insulation materials and costs for walls and ceilings. Get accurate estimates for fiberglass, cellulose, spray foam, and mineral wool insulation.

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Typical Insulation Costs by Type

Insulation Type	Installed $/sq ft (R-30)	DIY Friendly?	Best Application
Fiberglass Batts	$1.80 – $3.10	Yes	Walls, floors, standard cavities
Blown-in Cellulose	$2.45 – $4.25	Yes (rental blower)	Attics, existing walls
Blown-in Fiberglass	$2.20 – $3.80	Yes (rental blower)	Attics, irregular cavities
Spray Foam (open-cell)	$4.50 – $7.70	No — pro equipment	Air sealing + insulation combo
Spray Foam (closed-cell)	$6.30 – $10.75	No — pro equipment	Moisture barrier + structural, crawlspaces
Mineral Wool (Rockwool)	$2.60 – $4.50	Yes	Fire-rated walls, soundproofing

Installed costs include material and labor at R-30 equivalent. Actual costs vary by R-value, cavity depth, and accessibility.

Assumptions & Sources

Assumptions

Material pricing: Based on 2025 national averages from major retailers and insulation contractors. Spray foam pricing from certified installer quotes.
Labor rates: Labor multiplier of 1.3-3.0× material cost depending on insulation type. Blown-in and spray foam require specialized equipment and trained installers.
Wall area deduction: 15% subtracted from gross wall area to account for doors, windows, and framing members.
Energy savings: Estimated at $0.15/sq ft/year based on DOE averages. Actual savings depend on climate zone, existing insulation, and HVAC efficiency.
Regional multiplier: ZIP-code-based adjustment using RSMeans 2025 regional cost indices applied to both materials and labor.

Last updated: February 2026

Pro Tips from a Construction PM

R-value by climate zone: Zone 1 (Miami) needs R-13 walls / R-30 attic. Zone 6 (Minneapolis) needs R-20 walls / R-49 attic. Look up your zone and match code minimum at bare minimum.
Vapor barrier placement: Always on the warm side. Cold climates = interior face. Hot-humid climates (Gulf Coast) = exterior. Get this wrong and you trap moisture in the wall cavity — mold and rot within 2-3 years.
Don't stack batts to cheat R-value: Two layers of R-19 crammed into a 2×6 cavity doesn't give R-38 — compression kills performance. Use the right product for the cavity depth.
Attic ventilation matters equally: Sealing your attic tight without proper soffit-to-ridge ventilation creates a moisture trap. Install baffles at every rafter bay to keep air moving above the insulation.
Air seal first, insulate second: A $200 afternoon of caulking and foam around penetrations (wires, pipes, light boxes) outperforms $2,000 of insulation laid over leaky framing. Highest-ROI energy upgrade there is.

Related Calculators

Drywall Calculator — Estimate drywall sheets, mud, and tape if you're re-closing walls after insulation work.
HVAC Calculator — Calculate heating and cooling system costs — proper insulation reduces your required HVAC capacity and operating costs.
Roofing Calculator — Estimate roofing costs if your attic insulation project reveals roof deck issues that need addressing first.

Insulation Calculator by State

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