Insulation Calculator
Estimate insulation costs for your attic, walls, or crawl space. Compare material types, calculate energy savings, payback period, and available tax credits under the Inflation Reduction Act.
sqft
R
R
Estimated Total Installation Cost
$2,200
Range: $1,400 — $3,000
Material Cost (Mid)
$1,500
Installation Labor
$675
R-Value Added
+R-38
Inches Needed
12.3"
Est. Annual Energy Savings
$2,660
Simple Payback Period
0.8 yrs
DIY-friendly: Rental blower available at home improvement stores. DIY saves roughly 40–50% on labor.
Advanced
Advanced Analysis
Type comparison, area priority, DIY savings breakdown
All insulation types compared for your 1000 sqft attic adding R-38:
| Type | R/inch | Cost Range/sqft | DIY? | Est. Total | Payback |
|---|---|---|---|---|---|
| Fiberglass Batts | R-3.2 | $0.50–$1.50 | Yes | $1,500 | 0.6 yrs |
| Blown-In (Cellulose/Fiberglass) * | R-3.1 | $1.00–$2.00 | Yes | $2,250 | 0.8 yrs |
| Open-Cell Spray Foam | R-3.7 | $1.00–$2.00 | Pro Only | $2,250 | 0.8 yrs |
| Closed-Cell Spray Foam | R-6.5 | $2.00–$4.00 | Pro Only | $4,500 | 1.7 yrs |
| Rigid Board (XPS/Polyiso) | R-5.75 | $1.00–$3.00 | Yes | $3,000 | 1.1 yrs |
Pro
Professional Analysis
Tax credits, climate zone targets, building science guidance
IRA Section 25C: Insulation upgrades qualify for a 30% tax credit, capped at $1,200 per year through 2032. This applies to insulation material costs that meet minimum R-value requirements — not labor.
Project Cost (Mid)
$2,200
Before tax credit
30% Tax Credit
$660
IRA 25C credit (max $1,200/yr)
Net Cost After Credit
$1,540
Your true out-of-pocket
Adjusted Payback
0.6 yrs
With tax credit applied
Tip: The $1,200 annual limit resets each year. If your project exceeds the credit limit, consider splitting across two tax years or combining with other eligible improvements (windows, doors, heat pumps — each has separate limits).
How to Use This Insulation Calculator
Select your Area Type (attic, walls, or crawl space), enter the square footage to insulate, choose your insulation type, and input your current and target R-values. The calculator estimates total material and labor costs, annual energy savings, and how many years before the project pays for itself.
For attics, use the floor area below (same as your home's footprint). For walls, measure the total exterior wall area. For crawl spaces, use the floor area of the space below. R-value targets are based on DOE recommendations by climate zone — colder climates require higher R-values.
How Insulation Costs Are Calculated
Material Cost = Cost per Sqft × Area (sqft)
Total Installed Cost = Material Cost + Labor (40–60% of material)
Annual Energy Savings ≈ R-Value Added × Area × $0.07/sqft/R-point
Simple Payback = Total Cost ÷ Annual Savings (years)
IRA Tax Credit = min(Total Cost × 30%, $1,200) — primary residences only
Total Installed Cost = Material Cost + Labor (40–60% of material)
Annual Energy Savings ≈ R-Value Added × Area × $0.07/sqft/R-point
Simple Payback = Total Cost ÷ Annual Savings (years)
IRA Tax Credit = min(Total Cost × 30%, $1,200) — primary residences only
Example: Attic Blown-In Insulation
1,000 Sqft Attic — Blown-In from R-11 to R-49
| Area Type | Attic |
| Insulation Type | Blown-In Cellulose |
| R-Value Added | +R-38 (11 to 49) |
| Material Cost | ~$1,500 |
| Installed Cost (Mid) | ~$2,200 |
| After IRA Credit (30%) | ~$1,360 net |
| Annual Energy Savings | ~$266/yr |
| Simple Payback | ~5.1 years |
An attic insulation upgrade is typically the highest-ROI home energy improvement. Adding R-38 to an under-insulated 1,000 sqft attic can reduce heating and cooling costs by 15–20% annually, with payback under 6 years even before tax credits.
Insulation Type Comparison
Choosing the right insulation type depends on your space, budget, and whether you prefer DIY or professional installation:
- Fiberglass Batts ($0.50–$1.50/sqft, R-3.2/inch): Pre-cut rolls that fit between studs. The easiest DIY option — available at any hardware store. Best for open wall cavities and attic floors with regular joist spacing. Must not be compressed.
- Blown-In ($1–$2/sqft, R-2.5–3.7/inch): Loose cellulose or fiberglass blown in with a machine. Fills irregular spaces and is available for DIY with a rented blower. Ideal for adding insulation over existing in attics.
- Open-Cell Spray Foam ($1–$2/sqft, R-3.7/inch): Expands to fill gaps, doubling as an air barrier. Requires professional installation. Good for cathedral ceilings and hard-to-reach areas.
- Closed-Cell Spray Foam ($2–$4/sqft, R-6.5/inch): The highest R-value per inch of any common insulation. Also acts as a vapor barrier. Professional-only — the most expensive option but ideal for tight spaces needing maximum R-value with minimum thickness.
- Rigid Board ($1–$3/sqft, R-5–6.5/inch): Rigid panels of XPS, EPS, or polyisocyanurate foam. Used under siding, on basement walls, or in continuous insulation applications. DIY-possible with basic tools.
Frequently Asked Questions
Attic insulation costs $1,500–$4,500 for a typical 1,000 sqft attic, depending on the type. Blown-in cellulose runs $1–$2 per sqft installed; fiberglass batts cost $0.50–$1.50 per sqft. The DOE recommends R-38 to R-60 for attics, and most homes underperform this target. Professional installation adds 40–60% to material costs.
Blown-in cellulose or fiberglass is the most cost-effective for existing attics — it fills irregular spaces and can be rented DIY. Closed-cell spray foam offers the highest R-value per inch (R-6.5) and doubles as a vapor barrier, but costs $2–$4 per sqft and requires professional installation. Fiberglass batts are the easiest DIY option.
Properly insulating an under-insulated attic typically reduces heating and cooling costs by 10–20%, or $200–$600 per year for average US homes spending $2,000+ annually on energy. The exact savings depend on your current R-value, climate zone, heating/cooling system, and air sealing quality.
Yes. Under the Inflation Reduction Act (IRA) Section 25C, insulation upgrades in primary residences qualify for a 30% tax credit up to $1,200 per year through 2032. The credit applies to material costs that meet minimum R-value requirements. Rental properties and new construction do not qualify.
The DOE recommends R-38 to R-60 for attics, R-13 to R-21 for exterior walls, and R-19 to R-30 for crawl spaces — higher values in colder climate zones. You can check your current insulation by measuring its depth: 3.5" of fiberglass batts equals roughly R-11; 10" of blown-in cellulose equals roughly R-37.