How Much Does It Cost to Insulate a House? (2026)
Insulating a house costs about $1–$2.40 per square foot for fiberglass batts, $1–$2.50 for blown-in, and $3–$7 for spray foam, installed. A typical attic runs $1,500–$3,500, and whole-house insulation for an average home ranges from $3,000 to $10,000 depending on scope and material. The attic gives the fastest energy payback, so start there.
Insulation is one of the few home upgrades that pays you back every month through lower heating and cooling bills. But the cost swings widely depending on what you insulate — just the attic, or walls, floors, and crawlspaces too — and which material you choose.
This guide breaks down what it costs to insulate a house in 2026 by insulation type, by area, and for a whole home, then shows where your first dollar delivers the biggest energy savings.
Key takeaways
- Batts cost $1–$2.40/ft²; blown-in $1–$2.50; spray foam $3–$7.
- A typical attic runs $1,500–$3,500 installed.
- Whole-house insulation ranges from $3,000 to $10,000.
- The attic gives the fastest payback — insulate it first.
- Air-seal gaps before adding insulation for full performance.
Skip the math
Get instant numbers with the Insulation Calculator.
Insulation cost by type
The material you choose sets the per-square-foot price. Batts are cheapest and DIY-friendly, blown-in is ideal for attics, and spray foam costs the most but delivers the highest R-value per inch while air-sealing at the same time.
| Insulation type | Cost per ft² (installed) | Best for |
|---|---|---|
| Fiberglass batts | $1.00 – $2.40 | Walls, budget jobs |
| Blown-in cellulose | $1.00 – $2.50 | Attics, retrofits |
| Blown-in fiberglass | $1.00 – $2.00 | Attics, fast fill |
| Closed-cell spray foam | $3.00 – $7.00 | Air-sealing, rim joists |
Cost by area of the home
Where you insulate matters as much as the material. The attic is the cheapest and highest-impact area; walls and crawlspaces cost more per square foot because access is harder.
| Area | Typical cost | Notes |
|---|---|---|
| Attic | $1,500 – $3,500 | Highest energy return |
| Walls (retrofit blown-in) | $1.50 – $3.50 / ft² | Drilled and filled |
| Crawlspace / basement | $1,500 – $4,000 | Often needs a vapor barrier |
| Whole house | $3,000 – $10,000 | Depends on scope and material |
Where to spend first
The attic loses the most heat because warm air rises, so bringing it to R-38–R-60 delivers the biggest savings per dollar. After the attic, air-sealing gaps around penetrations, then insulating rim joists and crawlspaces gives the next-best return. Walls are worth doing during a remodel but are the most disruptive to retrofit.
How to estimate your insulation cost
Measure the square footage of the area you want to insulate, choose a material, and multiply by the installed price per square foot. Our insulation calculator does this for you and factors in the insulation type, giving a fast material-and-labor estimate you can take to contractors.