Insulation Calculator

Calculate insulation quantity, R-value and cost. Shows a potential credit only when selected; verify current eligibility.

Insulation Details

Including installation
Target R-Valueโ€”
Bags/Rolls Neededโ€”
Total Costโ€”
Potential Federal Credit (verify)โ€”
Net Cost After Creditโ€”

How to Calculate Insulation

Formula: Determine target R-value by climate zone and location. Calculate area. Divide by coverage per bag/roll at target R-value (check product label).

R-Value Recommendations

Climate ZoneAtticWall (2ร—4)Wall (2ร—6)Floor
1-2 (FL, TX, AZ)R-30R-13R-21R-13
3-4 (CA, GA, TN)R-38R-13R-21R-19
5-6 (NY, IL, WA)R-49R-13R-21R-25
7-8 (MN, AK, ND)R-60R-13R-21R-30

Insulation Type Comparison

TypeR/inch$/sq ft (installed)Best For
Fiberglass battR-3.2$0.80-1.50Walls, DIY
Blown fiberglassR-2.5$1.00-2.00Attics
CelluloseR-3.7$1.20-2.50Attics, dense walls
Spray foamR-5-6$1.50-3.50Air sealing, premium

FAQ

What R-value do I need?
Attic: R-30 (warm) to R-60 (cold). Walls: R-13 (2ร—4) or R-21 (2ร—6). Check DOE climate zone map.
How many bags for 1,000 sq ft attic?
At R-49: ~20-25 bags of blown fiberglass (coverage varies by product). Check bag label.
Tax credit for insulation?
Eligibility and limits depend on current IRS rules; verify before relying on this estimate.
Can I install over existing insulation?
Yes for attics (add unfaced batts or blown-in perpendicular). Never add faced insulation over existing faced insulation (moisture trap).

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