Insulation Cost Calculator 2026

Home insulation costs $1,200–$4,500 on average for a typical project in 2026. The most common project — blown-in insulation for a 1,000–1,500 sqft attic — runs $1,200–$2,800. Spray foam for an entire home costs $8,000–$20,000. The per-sqft cost ranges from $0.50 for basic batt insulation to $3.00+ for closed-cell spray foam.

Blown-in cellulose or fiberglass is the best choice for most attics — it achieves high R-values (R-49 to R-60 in cold climates) cost-effectively at $0.65–$1.20/sqft installed, fills gaps around joists better than batts, and can be added over existing insulation. Spray foam (open-cell) is preferred for unvented/conditioned attic assemblies — it seals the roof deck rather than the attic floor. Fiberglass batts between joists are adequate but leave more gaps than blown-in.

Properly insulating an attic typically reduces heating and cooling costs 10–20% annually. For a home spending $2,400/year on energy, that's $240–$480/year in savings. Payback period: 3–7 years for attic insulation, 5–10 years for wall insulation, 2–5 years for crawlspace/basement. Additional insulation beyond minimum code (R-38 to R-60 in cold climates) shows diminishing returns but still contributes to comfort and energy savings. The 30% federal tax credit (up to $1,200) under the IRA significantly improves the payback math.

Spray foam (closed-cell) is worth the premium in specific situations: (1) Rim joists and tight spaces where air sealing matters most. (2) Unvented attic assemblies where you want to condition the attic space. (3) Basements and crawlspaces with moisture concerns — closed-cell spray foam is a vapor barrier. (4) New construction where max R-value in limited wall cavity is needed. For standard attic insulation, blown-in fiberglass or cellulose provides 80–90% of the benefit at 30–40% of the cost. The federal tax credit helps close the gap for spray foam projects.

Batt insulation is the most DIY-friendly type — it comes in pre-cut rolls sized for standard stud spacing. A motivated homeowner can insulate an accessible attic floor with batt insulation for $300–$700 in materials vs. $1,500–$2,500 professionally installed. Blown-in insulation requires renting a blowing machine ($100–$150/day) but is manageable for attic floors. Spray foam requires professional equipment and training — DIY kits exist for small areas (rim joists, gaps) but are impractical for whole-house applications. Always wear N100 respirator and Tyvek suit when handling fiberglass batts or blown-in insulation.

Insulating a 1,500 sqft house costs $3,500–$9,000 total depending on which areas you're insulating and current condition. A typical package: attic blown-in (1,500 sqft) $1,800–$3,000 + air sealing $500–$1,000 + crawlspace/basement insulation $1,200–$2,500 + rim joist spray foam $300–$600. If the home has no wall insulation (common in pre-1980s construction), adding wall insulation via dense-pack blown-in (drilling through siding or drywall) adds $3,000–$8,000. The 30% federal tax credit (up to $1,200/year) applies to qualifying insulation materials, significantly reducing out-of-pocket cost. Most 1,500 sqft homes in cold climates spend $4,500–$7,500 for a complete insulation upgrade.

DOE recommends the following attic R-values by climate zone: Hot climates (Florida, Gulf Coast, Hawaii — Zone 1–2): R-30 to R-49. Warm-mixed (Southeast, Arizona — Zone 3): R-38 to R-49. Mixed (Mid-Atlantic, Pacific Northwest — Zone 4): R-49. Cool (Midwest, Northeast — Zone 5): R-49 to R-60. Cold (Northern states, Mountain — Zone 6–7): R-49 to R-60. Very cold (Alaska, high altitude — Zone 8): R-60. Most existing homes have R-11 to R-19 — significantly below modern recommendations. Adding R-30 to R-38 to an attic with R-11 is typically the single highest-ROI home energy improvement available. Find your climate zone at energy.gov using your zip code.