Attic insulation (fiberglass): cost & ROI
Adding fiberglass insulation in the attic. Cheap, invisible, and one of the few projects that reliably recoups more than it costs — buyers and appraisers value lower energy bills and comfort.
“Net value gain” means this project typically adds more resale value than it costs.
How much does a attic insulation (fiberglass) cost in 2026?
Adding attic insulation is one of the most quietly efficient projects a homeowner can do — it's cheap, cuts heating and cooling bills immediately, and recoups more than its cost at resale. In 2026 attic insulation averages around $2,500 nationally, ranging from roughly $1,500 for a small attic top-up to $4,500+ for a large attic with air sealing and higher R-value. It recoups about 110% of its cost, one of the highest returns of any project.
The value comes from energy performance for very little money. Air-sealing gaps and penetrations, then bringing the attic up to a modern R-value (typically R-49 to R-60 in most US climates), reduces the load on the HVAC system year-round. Fibreglass batts are the budget option; blown-in cellulose or fibreglass covers irregular spaces better; spray foam costs more but seals and insulates in one step. Because it's low-cost and improves the home's efficiency rating, it appeals to cost-conscious buyers.
| Scope | Typical installed cost | Notes |
|---|---|---|
| Small attic top-up | $1,500–$2,200 | Add blown-in over existing; minor air sealing. |
| Standard attic (national avg) | $2,200–$3,200 | Air seal + insulate to modern R-value, ~800–1,200 sq ft. |
| Large attic | $3,200–$4,500 | Bigger footprint, full air sealing, higher R-value. |
| Spray foam / full retrofit | $4,500–$8,000+ | Spray foam or remove-and-replace with premium materials. |
Ranges are 2026 US market figures compiled from industry cost guides; your local quote depends on size, finish and labour rates.
What a attic insulation (fiberglass) typically includes
- Air sealing gaps and penetrations
- Fiberglass batt or blown-in insulation
- Ventilation checks
- Disposal of old material
Pro tip: Keep the energy-bill savings and any efficiency rating documents — they make the value tangible to buyers.
How attic insulation (fiberglass) compares
Ranked by share of cost recouped at resale, attic insulation (fiberglass) is #5 of 32 projects we track.
What affects the cost
- Attic size
- Priced largely per square foot of attic floor — bigger attics cost more to bring up to R-value.
- Insulation type
- Fibreglass batts are cheapest; blown-in fills irregular spaces; spray foam costs most but air-seals as it insulates.
- Air sealing
- Sealing gaps, top plates and penetrations before insulating is inexpensive and multiplies the energy benefit.
- Existing conditions
- Removing old, damaged or contaminated insulation adds labour and disposal cost.
Attic insulation (fiberglass) cost by region
Costs vary by market. These are midrange estimates adjusted for regional price levels — always confirm with local quotes.
Full cost-by-location table (with ROI)
| Location | Estimated cost | Recouped |
|---|---|---|
| US National Average | $2,500 | 110% |
| New York, NY | $3,300 | 110% |
| Los Angeles, CA | $3,100 | 110% |
| Chicago, IL | $2,800 | 110% |
| Houston, TX | $2,500 | 110% |
| Phoenix, AZ | $2,400 | 110% |
| Miami, FL | $2,700 | 110% |
| Seattle, WA | $3,100 | 110% |
| Denver, CO | $2,700 | 110% |
| Atlanta, GA | $2,500 | 110% |
| Boston, MA | $3,200 | 110% |
| San Francisco, CA | $3,400 | 110% |
| London, UK | £2,100 | 110% |
| Manchester, UK | £1,800 | 110% |
| Birmingham, UK | £1,700 | 110% |
| Edinburgh, UK | £1,900 | 110% |
| Dublin, IE | €2,500 | 110% |
| Toronto, CA | C$3,600 | 110% |
| Vancouver, CA | C$3,800 | 110% |
| Sydney, AU | A$4,200 | 110% |
| Melbourne, AU | A$3,900 | 110% |
| Auckland, NZ | NZ$4,500 | 110% |
| Washington, DC | $2,800 | 110% |
| Philadelphia, PA | $2,900 | 110% |
| Minneapolis, MN | $2,700 | 110% |
| Austin, TX | $2,200 | 110% |
| Dallas, TX | $2,200 | 110% |
| Glasgow, UK | £1,800 | 110% |
| Bristol, UK | £1,900 | 110% |
| Calgary, CA | C$3,300 | 110% |
| Montreal, CA | C$3,100 | 110% |
| Brisbane, AU | A$4,000 | 110% |
| San Diego, CA | $3,000 | 110% |
| Portland, OR | $2,800 | 110% |
| Nashville, TN | $2,400 | 110% |
| Charlotte, NC | $2,300 | 110% |
| Tampa, FL | $2,500 | 110% |
| Leeds, UK | £1,700 | 110% |
| Perth, AU | A$4,100 | 110% |
| Adelaide, AU | A$3,400 | 110% |
| Wellington, NZ | NZ$4,200 | 110% |
| Christchurch, NZ | NZ$4,000 | 110% |
Before you spend
- Get 3 written quotes from licensed local contractors before committing
- Match finishes to what's normal for your neighbourhood, not above it
- Keep a 10–15% contingency for surprises once work starts
- Avoid overcapitalising — check what comparable homes nearby actually sell for
- If you're selling soon, weigh resale timing against how long the project will take
Frequently asked questions
How much does attic insulation cost in 2026?
About $2,500 on average, from roughly $1,500 for a small top-up to $4,500+ for a large attic with full air sealing.
Is attic insulation a good investment?
Yes — it's one of the highest-ROI projects, recouping around 110% of its cost thanks to immediate energy savings and its appeal to buyers.
What R-value should my attic be?
Most US climates call for roughly R-49 to R-60 in the attic. A local insulation contractor can confirm the target for your zone.
Which insulation type is best?
Blown-in cellulose or fibreglass offers the best value and coverage for most attics; spray foam costs more but seals air leaks in the same step.
Related cost guides
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How it compares
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Methodology
Figures are national midrange “Cost vs. Value” averages adjusted for finish, scope and region. They are planning estimates, not quotes or appraisals, and lean toward US/UK/Canada/Australia mid-markets. A recoup above 100% means national data shows this project typically adds more resale value than it costs — it's a genuine figure, but local results vary, so confirm with quotes. Reviewed June 2026. See our full methodology →
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