Attic Insulation Cost Calculator
Get an instant free estimate for attic insulation based on attic size, insulation type, target R-value, and existing insulation.
How is Attic Insulation Cost Calculated?
Attic insulation is priced per square foot of attic floor. The insulation type sets the base rate — from ~$1.40/sq ft for fiberglass batts to $5.50/sq ft for closed-cell spray foam — and is then scaled by your target R-value. Removing old insulation and air sealing are the main add-ons. A typical 1,000 sq ft attic with blown-in insulation at R-38 runs $1,500-$3,000 installed.
Estimate Your Project Cost
Project Location
Enter your state and zip code for a localized estimate.
Attic Size
Enter the attic floor area in square feet — usually close to the footprint of the floor below it.
Insulation Type:
Target R-Value:
Existing Insulation:
Additional Services:
Key Factors Influencing Attic Insulation Cost
Insulation Type & R-Value
The material is the biggest cost driver. Blown-in fiberglass and cellulose are the affordable, popular choices for attic floors; fiberglass batts are economical for accessible joists; and spray foam costs significantly more but air-seals and delivers the highest R-value per inch. Your target R-value (driven by climate) then scales the material quantity — colder climates need R-49 to R-60, while mild climates do well at R-30 to R-38.
Existing Insulation & Air Sealing
- Bare Attic / Add Over: Insulating a bare attic or topping up clean existing insulation is the lowest cost.
- Remove & Replace: Tearing out moldy, pest-damaged, or deteriorated insulation adds ~$1-$2/sq ft for labor and disposal.
- Air Sealing: Sealing gaps and penetrations before insulating maximizes savings and is often required for rebates.
Average Attic Insulation Cost by Type
| Insulation Type | Per Sq Ft | 1,000 Sq Ft Attic | Best For |
|---|---|---|---|
| Fiberglass Batts | $1.00 - $1.80 | $1,000 - $1,800 | Accessible joists, DIY |
| Blown-In Fiberglass | $1.20 - $2.00 | $1,200 - $2,000 | Fast coverage, most popular |
| Blown-In Cellulose | $1.40 - $2.20 | $1,400 - $2,200 | Dense, eco-friendly |
| Open-Cell Spray Foam | $3.00 - $4.50 | $3,000 - $4,500 | Air seal + insulate |
| Closed-Cell Spray Foam | $5.00 - $7.00 | $5,000 - $7,000 | Max R/inch, moisture barrier |
Common Add-Ons
| Add-On | Cost | Notes |
|---|---|---|
| Remove Old Insulation | $1.25/sq ft | Tear out and bag/dispose deteriorated insulation. |
| Air Sealing | $0.75/sq ft | Seal gaps and penetrations before insulating. |
| Vapor Barrier | $0.40/sq ft | Vapor retarder to manage moisture. |
| Soffit Baffles | $0.20/sq ft | Maintain soffit-to-ridge airflow above insulation. |
| Attic Hatch Insulation | ~$150 | Insulate and weatherstrip the attic access. |
How to Estimate Attic Insulation Cost Manually
Attic insulation is priced per square foot of attic floor. The insulation type sets the base rate, and your target R-value plus any old-insulation removal adjust it.
Step 1: Measure the Attic
Use the attic floor area — roughly the square footage of the top living floor. A 1,000 sq ft attic is typical for a mid-size single-story home; multi-story homes have an attic matching just the top floor's footprint.
Step 2: Pick the Insulation Type
Base installed rates per sq ft (at R-38):
- Fiberglass Batts: ~$1.40/sq ft — DIY-friendly, good for accessible joists
- Blown-In Fiberglass: ~$1.50/sq ft — fast, fills gaps, most popular
- Blown-In Cellulose: ~$1.65/sq ft — dense, eco-friendly recycled material
- Open-Cell Spray Foam: ~$3.50/sq ft — air seal + insulation
- Closed-Cell Spray Foam: ~$5.50/sq ft — highest R per inch, moisture barrier
Step 3: Target R-Value & Removal
Multiply the base by the R-value factor (R-19 0.70×, R-30 0.85×, R-38 1.0×, R-49 1.20×, R-60 1.40×). If old insulation must be torn out and disposed, add ~$1.25/sq ft. Adding over existing insulation or insulating a bare attic adds nothing extra to the base.
Step 4: Apply the Formula
Sq Ft × (Type Rate × R-Value) + Removal + Add-ons = Total
Example: 1,000 sq ft, blown-in cellulose ($1.65/sq ft), R-49 (×1.20), remove old (+$1.25/sq ft): 1,000 × ($1.65×1.20) + 1,000 × $1.25 = $1,980 + $1,250 = $3,230.
Frequently Asked Questions
In 2026, attic insulation costs $1,500-$4,000 for a typical home, or roughly $1.50-$4.00 per square foot installed for common materials. Blown-in fiberglass and cellulose — the most popular attic options — run about $1.40-$2.00/sq ft, while spray foam costs $3.50-$7.00/sq ft. For an average 1,000-1,200 sq ft attic, expect $1,800-$3,500 for blown-in insulation at a typical R-38 to R-49. Costs rise with higher R-values, spray foam, and if existing insulation must be removed and disposed of first.
The recommended attic R-value depends on your climate zone. The U.S. Department of Energy recommends roughly R-30 to R-49 for warm/mild southern climates and R-49 to R-60 for cold northern climates. As a rule of thumb, most attics benefit from R-38 to R-49; colder regions and energy-focused upgrades target R-60. Higher R-value means better thermal resistance and lower heating/cooling bills, but with diminishing returns — going from nothing to R-38 saves far more than going from R-49 to R-60. Check the DOE zone map for your area, or your local energy code, for the recommended target.
It depends on your attic and goals. Blown-in fiberglass and cellulose are the most popular and cost-effective for attic floors — they're fast to install, fill irregular gaps and around obstructions, and reach high R-values affordably. Fiberglass batts work well for accessible, evenly-spaced joists and are DIY-friendly. Spray foam (open or closed cell) is the premium option: it air-seals as it insulates and has the highest R-value per inch, making it ideal for converting attics to conditioned space or sealing complex rooflines — but it costs 2-4× as much. For a standard vented attic floor, blown-in is usually the best value; for sealing the roofline or a conditioned attic, spray foam excels.
It depends on the condition of the existing insulation. If the old insulation is dry, clean, and free of mold, pests, and damage, you can usually add new insulation directly on top (called 'topping up') — this is cheaper and faster. You should remove and replace the old insulation if it's: water-damaged or moldy, infested with rodents or pests (droppings/contamination), compressed or deteriorated, or contains older materials of concern (e.g., vermiculite, which may contain asbestos and requires special testing/handling). Removal adds about $1-$2/sq ft for the labor and disposal, but starting fresh ensures a healthy, effective result.
Air sealing is highly recommended and often the single most cost-effective part of an attic insulation project. Insulation slows heat transfer, but it doesn't stop air leakage — gaps around can lights, plumbing/wiring penetrations, the attic hatch, and top plates let conditioned air escape and outside air in, undermining the insulation's effectiveness. Sealing these gaps with caulk and foam before adding insulation maximizes energy savings and prevents moisture problems. Many energy professionals consider air sealing essential for getting the full benefit of new insulation, and it's frequently required to qualify for energy rebates.
Yes — in 2026, the federal Energy Efficient Home Improvement Credit (25C) offers a tax credit of 30% of the cost of qualifying insulation and air sealing materials, up to $1,200 per year. Many state energy offices and local utilities also offer insulation rebates, sometimes substantial, since insulation reduces grid demand. To qualify, the insulation typically must meet certain R-value/efficiency criteria, and air sealing is often included. Keep your receipts and the manufacturer's certification statement. Check the ENERGY STAR rebate finder, your utility's website, and consult a tax professional to maximize the incentives, which can offset a meaningful share of the project cost.
Some types are DIY-friendly, others aren't. Fiberglass batts are the most DIY-accessible — you cut and lay them between joists (wear protective gear: gloves, mask, long sleeves, since fiberglass irritates skin and lungs). Blown-in insulation can be DIY using a rented blower machine (often free with material purchase), but it's a two-person job and getting even coverage in a hot, cramped attic is challenging. Spray foam should always be left to professionals — it requires special equipment, precise mixing, and proper ventilation, and mistakes are costly and hazardous. Also note: DIY work may not qualify for some rebates that require professional installation, and proper air sealing and ventilation detailing benefit from a pro's experience.
Attic insulation lasts a long time: blown-in fiberglass and cellulose last 20-30+ years (cellulose may settle ~20% over time, slightly reducing R-value), batts last 20-30 years, and spray foam can last the life of the home (80+ years). On savings, the EPA estimates homeowners can save about 15% on heating and cooling costs (around 11% of total energy costs) by air sealing and adding insulation in attics and other areas — often more for homes that were severely under-insulated. The payback period for attic insulation is typically just a few years, making it one of the highest-ROI energy upgrades, on top of improved comfort and reduced drafts.