Source-backed insulation guide
Attic Insulation Cost Calculator
HomeGuide reports attic insulation at $1 to $4 per square foot installed. DWELVRA uses that as the base planning range and keeps R-value, material and removal as separate scope decisions.
Quick answer
$1–$4 per square foot installed
Source basis: HomeGuide, 2026 cost guide. DWELVRA's “modeled typical” value is the arithmetic midpoint of a published range, not a measured national average.
Attic Insulation Cost Calculator
Use this as a planning range, not a contractor quote. Only the inputs shown in the calculator affect the result; no hidden regional or complexity multiplier is applied.
Estimated project cost
Actual pricing can differ because contractor scope, location, access, materials and site conditions vary. DWELVRA is an independent informational publisher, not a contractor or professional estimator.
Modeled examples
| Project input | Low | Modeled typical | High |
|---|---|---|---|
| 500 sq ft | $500 | $1,250 | $2,000 |
| 1,000 sq ft | $1,000 | $2,500 | $4,000 |
| 1,500 sq ft | $1,500 | $3,750 | $6,000 |
| 2,000 sq ft | $2,000 | $5,000 | $8,000 |
Modeled typical values are calculated midpoints. They should not be described as source-published averages unless a source explicitly labels them that way.
Material-specific context
HomeGuide reports blown-in attic insulation at $0.90–$2.40 per square foot and attic spray foam at $1.50–$5.00 per square foot, depending on type, R-value and job size. Those material-specific ranges are not blended into the general calculator.
Air sealing and removal
Angi's July 9, 2026 attic-insulation guide reports air sealing at $250–$750 and old-insulation removal at $1–$1.50 per square foot when needed. They are not automatic add-ons because not every attic requires the same preparation.
R-value matters
ENERGY STAR explains that R-value measures resistance to heat flow and publishes climate-zone recommendations. For existing homes, recommended attic levels vary by climate and current insulation, so the right target should not be inferred from cost alone.
Safety note
ENERGY STAR warns that some older vermiculite insulation may contain asbestos and should not be disturbed until properly evaluated. Attics also present fall, heat and electrical hazards.
What can change the final quote?
- Attic size
- Target R-value
- Existing insulation
- Material type
- Air sealing
- Removal and disposal
- Access and obstructions
- Climate zone
These factors are not represented by hidden multipliers unless the calculator explicitly asks for them.
Questions to ask before hiring
- What R-value is being proposed and why?
- Is air sealing included before insulation?
- Is old insulation removal needed?
- What material and installed depth are specified?
- How will recessed lights, vents and soffit airflow be handled?
- Will final R-value documentation be provided?
FAQ
How much does attic insulation cost?
HomeGuide reports $1–$4 per square foot installed and $1,000–$2,700 as a common total range.
What R-value should I choose?
It depends on climate zone and existing insulation. ENERGY STAR provides retrofit guidance by zone.
Does the calculator include air sealing or removal?
No. Those are separate, condition-dependent scopes.
Methodology
DWELVRA records the source, date, unit and project scope behind each published cost range. Calculator arithmetic is intentionally simple and visible. Different publishers' datasets are not silently averaged together. Condition-dependent extras stay outside the base formula unless a source supports a clear, comparable adjustment.
Sources
- HomeGuide — Attic Insulation Cost — 2026 guide
- Angi — Attic Insulation Cost — July 9, 2026
- ENERGY STAR — Recommended Home Insulation R-Values — Current guidance
- ENERGY STAR — Adding Attic Insulation — Current guidance