How Much Does Insulation Cost? (2026 Prices by Type)
Installed insulation runs $0.50–$3.50/sqft depending on type. Here's the full breakdown — and why R-value matters more than material.
Here's what you're actually going to pay, installed, for the most common insulation types in 2026:
| Type | Cost per Sqft (Installed) | DIY? | |------|--------------------------|------| | Fiberglass batts | $0.50–$1.50 | Yes | | Blown-in cellulose | $1.00–$2.00 | Rental machines available | | Blown-in fiberglass | $1.00–$1.80 | Rental machines available | | Spray foam (open-cell) | $1.00–$2.00 | No — requires pro | | Spray foam (closed-cell) | $1.50–$3.50 | No — requires pro |
These are installed prices. Material-only is about 30–50% less if you're doing the work yourself.
You're Buying R-Value, Not Insulation
This is the thing most people miss. The point isn't to buy fiberglass or cellulose — the point is to hit a target R-value for your climate zone. R-value is the measure of thermal resistance: higher is better, and the relationship is direct. R-49 blocks roughly twice as much heat transfer as R-25.
The U.S. Department of Energy recommends R-49 to R-60 for attics in cold climates, and R-30 to R-49 in moderate climates. Walls are typically R-13 to R-21 for 2×4 framing, R-19 to R-25 for 2×6.
Different materials hit different R-values per inch:
- Fiberglass batts: R-3.1 per inch
- Cellulose (blown-in): R-3.5 per inch
- Open-cell spray foam: R-3.7 per inch
- Closed-cell spray foam: R-6.5 per inch
So if you want R-49 in your attic, you need about 14 inches of fiberglass or cellulose, but only 7.5 inches of closed-cell foam. Spray foam wins on thickness — but at 3× the cost.
Attic First, Always
If you're insulating on a budget, the attic is where your money goes furthest. Heat rises. In winter, your biggest heat loss is through the ceiling. In summer, your biggest heat gain is through the roof.
Going from R-19 to R-49 in your attic — a very common scenario in older homes — can cut heating and cooling costs by 15–20%. That same money spent insulating walls? Maybe 5% savings.
A 1,000 sqft attic floor insulated with blown-in cellulose to R-49 (about 14 inches) costs $1,000–$2,000 installed. For most homeowners, that pays back in 3–5 years through lower energy bills.
Walls are still worth doing — especially if you're opening them up for a renovation anyway — but prioritize the attic first.
DIY vs. Hiring a Pro
Fiberglass batts are the most DIY-friendly insulation. You measure, cut, and staple them between studs or joists. No special equipment, no training. A roll of R-15 batt for a 2×4 stud bay costs about $1.20 per sqft at the home center.
Blown-in cellulose and fiberglass can also be DIY if you rent a blowing machine — Home Depot and Lowe's often lend them free when you buy enough bags. But the setup takes some learning, and you'll need to build or buy baffles at the eaves to keep the blown-in from blocking the soffit vents.
Spray foam is not a DIY job. The two-component chemistry requires proper equipment, training, and respiratory protection. Hiring a spray foam contractor is the right call — and they can often do a better job than any DIYer regardless.
The Federal Tax Credit
The 25C energy efficiency tax credit covers 30% of insulation installation costs, up to $1,200 per year. That means a $2,000 attic insulation job could net you $600 back at tax time. Keep your receipts and file IRS Form 5695.
The credit applies to qualifying insulation materials installed in your primary residence. It does not cover labor for standard batt installation, but it does cover the full installed cost of blown-in and spray foam since those are inseparable from the material.
Use our insulation cost calculator to estimate the total cost for your project by area, R-value, and insulation type.
Frequently Asked Questions
- How much does insulation cost per square foot?
- Batt insulation runs $0.30–$1.00 per square foot installed. Blown-in cellulose or fiberglass costs $0.60–$1.50 per sq ft. Spray foam is the most expensive at $1.50–$4.50 per sq ft for open-cell and $3–$7 for closed-cell. Material-only costs are roughly 30–50% of installed prices.
- What type of insulation gives the best R-value per dollar?
- Blown-in fiberglass and cellulose offer good R-value at lower cost — roughly $0.02–$0.04 per R-value per square foot. Closed-cell spray foam has the highest R-value per inch (R-6 to R-7 per inch) but costs significantly more per R-value achieved. For most attics and walls, blown-in or batt insulation gives the best return.
- What R-value do I need in my attic?
- The Department of Energy recommends R-38 to R-60 for attics in most of the US (Climate Zones 3–7). Southern climates need R-30 to R-49, while northern climates need R-49 to R-60. Adding insulation to an under-insulated attic is one of the highest-ROI home improvements you can make.
- Is spray foam insulation worth the higher cost?
- Closed-cell spray foam is worth it in specific applications: rim joists, crawl spaces, cathedral ceilings where depth is limited, and anywhere you need an air barrier in addition to insulation. For open wall cavities and attics where you have space for thicker batts or blown-in, the premium usually isn't justified.
- Can I claim a tax credit for insulation?
- Yes — as of 2025, the Energy Efficient Home Improvement Credit (Form 5695) covers 30% of insulation costs up to $1,200 per year for adding insulation to your primary residence. The credit applies to qualifying materials; labor for standard batt installation isn't covered, but the full installed cost of blown-in and spray foam qualifies.