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Blown-In Fiberglass & Cellulose · R-49 / R-60 · Air Sealing · Old RemovalAttic insulation & air sealing replacement cost calculator
Topping up an attic to ENERGY STAR R-49 with blown-in fiberglass or cellulose runs $1,650 to $3,600 for a 1,500 sq ft attic, while vacuuming out old water-damaged or rodent-soiled insulation, foam-sealing top plates, adding soffit baffles, and blowing fresh R-49/R-60 runs $3,600 to $7,200.
Reviewed 25 October 2026 · Written by Mantu Kumar
See the illustrated inspection guide · Interactive system diagram
Written and maintained byMantu Kumar
Evidence review16 October 2026
Calculation rulesRead the methodology
Quality standardEditorial policy
Key facts at a glance
- Blown-in fiberglass or cellulose top-up (adding R-30 to reach R-49) runs $1.10–$2.30 per sq ft ($1,650–$3,450 for a 1,500 sq ft attic).
- Full R-49 to R-60 blown-in install on a bare attic floor runs $1.65–$3.10 per sq ft ($2,475–$4,650 for 1,500 sq ft).
- Attic air sealing + rafter soffit ventilation baffles adds $0.45–$1.10 per sq ft ($675–$1,650)—and delivers the biggest winter heating and ice-dam savings.
- HEPA vacuum removal of old wet, moldy or rodent-soiled insulation adds $1.00–$2.25 per sq ft ($1,500–$3,375 for 1,500 sq ft).
- Open-cell or closed-cell spray foam (unvented roof deck encapsulation) runs $3.65–$7.60 per sq ft ($5,475–$11,400+ for 1,500 sq ft).
Sources: U.S. DOE & ENERGY STAR Recommended Home Insulation R-Values (Zones 1–8), 2026 International Energy Conservation Code (IECC), and insulation contractor benchmarks.
2026 planning ranges
- 1Blown-in or batts · $1.10–$2.80 / sq ft
- 2Rafter baffles at the soffit
- 3Air sealing: plates, chases, cans
- 4Spray foam on the deck · $3.50–$7.50
- 5Old insulation vacuumed out
- 6Ridge & soffit ventilation
- 7Target R-value by climate
- 8Can lights and the hatch
- 9Bath fans vented outside
R-value by depth: Cellulose ~R-3.7 per inch Blown fiberglass ~R-2.7 R-49 ≈ 13–18 in settled
Attic insulation, air sealing & removal cost estimator
No email · nothing sentDiagram, part by part
Attic insulation & air sealing replacement: every numbered part explained
The attic insulation & air sealing replacement drawing above has 9 numbered parts, from Blown-in or batts to Bath fans vented outdoors. Each card below frames one of them, and after you run the calculator it shows what that part adds to your estimate.
1 Blown-in or batts
$1.10–$2.80 / sq ft
Loose-fill fiberglass or cellulose is blown across the attic floor to the depth your climate calls for, often R-49 to R-60 in cold zones. Batts suit open joists with easy access, but they leave gaps around wiring and blocking unless they are cut carefully.
What moves it: Attic floor area, the R-value you are aiming for and how much useful insulation is already there.
On the quote: Ask for the target R-value and the installed depth in inches, not only the number of bags.
2 Rafter baffles at the soffit
Included with air sealing
Baffles stapled between the rafters at the eaves hold insulation back from the soffit vents, so outside air can still flow up under the roof deck. Without them, new insulation often buries the intake and the attic stays damp in winter.
What moves it: The number of rafter bays along each eave and whether old baffles are crushed or missing.
On the quote: Check that the quote lists one baffle per rafter bay along every eave that has soffit vents.
3 Air sealing: plates, chases, cans
Air sealing closes the gaps around top plates, plumbing and wiring chases, recessed lights and the attic hatch before insulation goes down. Warm, moist air leaking through those gaps causes much of the heat loss and frost in attics, so sealing often saves as much energy as the insulation itself.
What moves it: How many penetrations the ceiling has, recessed light count and how open the attic is to work in.
On the quote: Ask which leaks they will seal, the materials used and whether recessed lights get covers rated for contact with insulation.
4 Spray foam on the deck
$3.50–$7.50
Spray foam applied to the underside of the roof deck turns the attic into part of the conditioned house. It costs several times more than blown insulation and changes how the roof is vented, so it is a design decision rather than a simple upgrade.
What moves it: Roof area rather than floor area, open-cell or closed-cell foam, and the thickness required.
On the quote: Ask whether the roof vents will be closed, how the foam meets code for ignition barriers and what it means for the shingle warranty.
5 Old insulation vacuumed out
Wet, moldy, rodent-damaged or badly compressed insulation is vacuumed out with a high-powered HEPA machine and bagged before new insulation goes in. Blowing new material over contaminated insulation traps odor and moisture.
What moves it: Attic area, the depth of the old insulation and how far the bags must be carried.
On the quote: Confirm removal and disposal are priced, and ask how the house is protected from dust during vacuuming.
6 Ridge & soffit ventilation
Checked, not priced here
Soffit vents let cool air in low and ridge or roof vents let it out high. When intake and exhaust are balanced, the attic stays drier in winter and cooler in summer, which protects both the insulation and the roof deck.
What moves it: The existing vent layout and how much soffit intake is open.
On the quote: Ask the installer to confirm intake and exhaust are balanced before insulating, and price any vent work separately.
7 Target R-value for your climate
R-30 top-up · R-49 to R-60 full depth
The material you choose sets how deep the insulation must be. Cellulose gives about R-3.7 per inch and blown fiberglass about R-2.7, so reaching R-49 takes roughly 13 inches of cellulose or 18 inches of fiberglass. Colder climates call for the higher target; a top-up adds depth over clean existing insulation.
What moves it: Your climate zone, the material and the depth already in place.
On the quote: Ask for depth markers stapled to the joists so you can check the installed depth after the job.
8 Recessed lights and the attic hatch
Covered with air sealing
Older recessed lights and an unsealed attic hatch are two of the biggest air leaks in a ceiling. Lights that are not rated for insulation contact need covers, and the hatch needs weatherstripping and a dam so loose fill does not spill when it is opened.
What moves it: The number and type of recessed lights and the hatch style.
On the quote: Ask how each light will be covered or replaced and whether the hatch gets weatherstripping and an insulated cover.
9 Bath fans vented outdoors
Separate trade, not priced here
A bathroom fan that blows into the attic adds moisture right where new insulation goes, which leads to mold and wet sheathing. Fans should be ducted through the roof or a wall to the outside before insulation is blown in.
What moves it: How many fans there are and where their ducts end today.
On the quote: Ask the installer to check every fan duct and price rerouting separately if any end in the attic.
Air seal first, insulate second
Why blowing 16 inches of insulation over unsealed drywall gaps wastes half your money
Fluffy fiberglass and cellulose slow conductive heat transfer, but warm indoor air still pushes right through them like a sweater in the wind unless the drywall top plates, plumbing chases, and recessed light cans are air-sealed with foam first.
Three close-ups from the photo above, and what each one means for an attic insulation & air sealing quote. These close-ups are crops of the same AI-generated illustration.
Keep soffit vents clear with rafter chutes
Without rigid foam or cardboard rafter baffles ($3–$6 per bay), blown-in insulation spills into the eaves and chokes off your soffit vents—causing attic condensation and winter ice dams.
Verify settled depth & bag count
Cellulose settles roughly 15% after blowing (requiring ~15 inches initial depth for R-49 settled), while blown fiberglass settles <2% (~18 inches for R-49). Require stapled cardstock depth rulers across the attic.
Before you sign a quote or file a claim, verify these three details
- Bag count & coverage chart
- How many manufacturer bags of cellulose or fiberglass the contractor guarantees on the invoice (e.g., ~58 bags of cellulose for R-49 across 1,500 sq ft)
- Recessed IC vs non-IC lights
- Whether older non-IC recessed can lights are boxed with fire-rated covers or swapped for sealed LED wafer lights before burying them in insulation
- Attic hatch & pull-down stair cover
- Whether the quote includes a 16-inch rigid foam dam around the attic scuttle hole and an insulated zip-up tent over pull-down stairs
On this page
- 2026 attic insulation cost per sq ft by material & R-value
- ENERGY STAR recommended attic R-values by climate zone (R-38 to R-60)
- Worked example: 1,500 sq ft attic (removal + air sealing + R-49)
- When homeowners insurance pays to replace wet or storm-damaged insulation
- Attic insulation and air sealing cost by region
- What “Insulation material & target R-value” does to the price
- What “Old insulation removal” does to the price
- How age changes the attic insulation and air sealing claim payout
- Quote checklist: 6 items to verify
- How long the job takes
- Ways to keep the cost down
- Sources and further reading
- Frequently asked questions
Attic insulation and air sealing cost per square foot by material (2026)
| Material / Service Scope | R-Value per Inch | 2026 Rate / Sq Ft | 1,500 Sq Ft Attic Total |
|---|---|---|---|
| Blown-In Fiberglass Top-Up (+R-30 over existing) | R-2.5 – R-2.8 / in | $1.10 – $2.15 / sq ft | $1,650 – $3,225 |
| Blown-In Cellulose Top-Up (+R-30 over existing) | R-3.5 – R-3.8 / in | $1.20 – $2.35 / sq ft | $1,800 – $3,525 |
| Full R-49 / R-60 Blown-In (Bare Attic Floor) | 15"–20" depth | $1.65 – $3.10 / sq ft | $2,475 – $4,650 |
| Fiberglass or Mineral Wool Batts (R-38 to R-49) | R-3.1 – R-3.7 / in | $1.50 – $3.40 / sq ft | $2,250 – $5,100 |
| Open-Cell Spray Foam (Unvented Roof Deck) | R-3.6 – R-3.9 / in | $3.65 – $5.80 / sq ft | $5,475 – $8,700 (at pitch) |
| Closed-Cell Spray Foam (Vapor Barrier Roof Deck) | R-6.5 – R-7.0 / in | $4.80 – $7.60 / sq ft | $7,200 – $11,400+ |
| Add-On: Air Sealing + Rafter Soffit Baffles | Stops stack effect | +$0.45 – $1.10 / sq ft | +$675 – $1,650 |
| Add-On: HEPA Vacuum Removal of Old Insulation | Wet/rodent/vermiculite | +$1.00 – $2.25 / sq ft | +$1,500 – $3,375 |
ENERGY STAR recommended attic R-values by U.S. climate zone (R-38 to R-60)
According to the U.S. Department of Energy and ENERGY STAR, if you can see the tops of your ceiling wood joists (2×6 joists = ~R-15; 2×8 joists = ~R-19), you have less than half the recommended insulation depth:
| DOE Climate Zone & Region | Target Total Attic R-Value | Blown Fiberglass Depth | Blown Cellulose Depth |
|---|---|---|---|
| Zone 1 (South FL, Hawaii) | R-30 to R-49 | 11" – 18" | 8.5" – 14" |
| Zones 2–3 (TX, Gulf Coast, Southeast, CA, Southwest) | R-38 to R-60 | 14" – 22" | 10.5" – 16.5" |
| Zone 4 (Mid-Atlantic, Lower Midwest, Pacific NW) | R-49 to R-60 | 18" – 22" | 13.5" – 16.5" |
| Zones 5–8 (New England, NY, Upper Midwest, Mountain) | R-49 to R-60 | 18" – 22" | 13.5" – 16.5" |
Worked example: 1,500 sq ft attic — vacuum removal, air sealing & new R-49 cellulose
1,500 sq ft attic · Removal + air sealing + R-49 blown-in
Worked example| Line Item | 2026 Planning Range |
|---|---|
| HEPA vacuum extraction & disposal of old insulation (1,500 sq ft) | $1,500 – $3,000 |
| Foam air-sealing top plates, chases & rafter soffit baffles | $675 – $1,500 |
| New R-49 blown-in cellulose or fiberglass blanket (1,500 sq ft) | $2,250 – $3,900 |
| Turnkey attic restoration & R-49 upgrade total | $4,425 – $8,400 |
If your existing attic insulation is dry, clean, and mold-free, do not pay to vacuum it out—simply air-seal accessible penetrations, install soffit baffles, and blow new insulation right on top for $2,325 to $4,950 total.
Does homeowners insurance cover replacing wet or rodent-damaged attic insulation?
- Covered Storm Roof Leaks, Ice Dams & Plumbing Bursts: On a covered water or wind claim, vacuuming out wet insulation and blowing new code-depth insulation is a standard covered line item—check our Water Damage Restoration Calculator.
- Rodent / Squirrel Nesting & Routine Energy Upgrades: Insulation contaminated by mice, rats, raccoons, or bats is excluded under the Vermin/Rodent Exclusion in standard HO-3 policies.
Attic insulation and air sealing cost by region
The calculator's default attic insulation and air sealing job, repriced for each of its six regions. At the national average it runs $3,150 – $6,150; South / Lower Midwest is the lowest at $2,741 – $5,351, and West Coast metro is the highest at $4,095 – $7,995, a gap of about $1,999 at the midpoint.
| Region | Planning range | Midpoint |
|---|---|---|
| National average | $3,150 – $6,150 | $4,650 |
| South / Lower Midwest | $2,741 – $5,351 | $4,046 |
| Mountain / Plains | $2,993 – $5,843 | $4,418 |
| Mid-Atlantic / Upper Midwest | $3,528 – $6,888 | $5,208 |
| Northeast metro | $3,969 – $7,749 | $5,859 |
| West Coast metro | $4,095 – $7,995 | $6,045 |
What “Insulation material & target R-value” does to the price
Every other input stays at its default and only “Insulation material & target R-value” changes. The cheapest choice, Blown-in fiberglass/cellulose top-up (+R-30 over clean base), comes to $2,325 – $5,025; the most expensive, Closed-cell spray foam on roof deck (vapor barrier), comes to $7,200 – $11,400.
| Choice | Planning range | Midpoint vs default |
|---|---|---|
| Blown-in fiberglass/cellulose top-up (+R-30 over clean base) | $2,325 – $5,025 | −$975 |
| Full R-49 / R-60 blown-in cellulose (R-3.7/inch) (default) | $3,150 – $6,150 | — |
| Full R-49 / R-60 blown-in fiberglass (R-2.7/inch) | $3,000 – $5,925 | −$188 |
| Unfaced fiberglass / mineral wool batts (R-38 to R-49) | $3,075 – $6,750 | +$262 |
| Open-cell spray foam on roof deck (unvented attic) | $5,475 – $8,700 | +$2,438 |
| Closed-cell spray foam on roof deck (vapor barrier) | $7,200 – $11,400 | +$4,650 |
What “Old insulation removal” does to the price
Every other input stays at its default and only “Old insulation removal” changes. The cheapest choice, Keep existing clean insulation (blow over top), comes to $3,150 – $6,150; the most expensive, HEPA vacuum removal & disposal of wet/soiled insulation, comes to $4,650 – $9,525.
| Choice | Planning range | Midpoint vs default |
|---|---|---|
| Keep existing clean insulation (blow over top) (default) | $3,150 – $6,150 | — |
| HEPA vacuum removal & disposal of wet/soiled insulation | $4,650 – $9,525 | +$2,438 |
How age changes the attic insulation and air sealing claim payout
Using the default job, a $1,000 deductible and a 35-year expected life. At 10 years old, about $1,329 is held back as depreciation; a replacement cost policy releases it after the work is finished, while an actual cash value policy keeps it.
| Age | Wear | First check | Held back |
|---|---|---|---|
| 2 years | 6% | $3,384 | $266 |
| 5 years | 14% | $2,986 | $664 |
| 10 years | 29% | $2,321 | $1,329 |
| 15 years | 43% | $1,657 | $1,993 |
| 20 years | 57% | $993 | $2,657 |
| 30 years | 80% | $0 | $3,720 |
Quote checklist: 6 items to verify
Insulation quotes are easiest to compare by R-value and area.
- Target R-value. And the installed depth.
- Area. Square feet of attic floor.
- Air sealing. Top plates, penetrations and the attic hatch.
- Baffles. At the soffits.
- Removal. Old insulation, if needed.
- Rebates. Utility programs and paperwork.
How long the job takes
| Stage | Typical time | What happens |
|---|---|---|
| Energy audit | 1 – 3 hours | Optional blower door test. |
| Air sealing | 0.5 – 1 day | Before insulation. |
| Blowing insulation | 2 – 6 hours | Typical attic. |
| Removal (if needed) | +1 day | Vacuum truck. |
Ask for the bag count and installed depth markers so you can confirm the R-value delivered.
Ways to keep the cost down
Insulation costs are low compared with savings.
- Air seal first. Bigger effect.
- Use blown insulation. Lower cost.
- Check rebates. Utility programs.
- Remove only when needed. Damaged insulation.
- Add baffles. Keep venting.
- Do it before reroofing. Ventilation planning.
Sources and further reading
- ENERGY STAR — Seal and insulate
- ENERGY STAR — Recommended insulation R-values
- U.S. Department of Energy — Insulation
Frequently asked questions
How much does it cost to insulate a 1,500 sq ft attic in 2026?
Adding blown-in fiberglass or cellulose over existing clean insulation to reach R-49 typically costs $1,650 to $3,525 ($1.10 to $2.35/sq ft) for a 1,500 sq ft attic. Including air sealing and soffit baffles brings the total to $2,325 to $5,100. Full vacuum removal, air sealing, and R-49 replacement runs $4,400 to $8,400.
Is blown-in cellulose or fiberglass better for an attic?
Borate-treated cellulose ($1.20–$2.35/sq ft) has a higher R-value per inch (R-3.7 vs R-2.6) and resists airflow better in cold climates. Blown-in fiberglass ($1.10–$2.15/sq ft) is lighter on ceiling drywall, won't absorb moisture, and settles less than 2%.
Should I remove old attic insulation before blowing in new insulation?
Only if the old insulation is wet from a roof leak, moldy, contaminated by rodent droppings/urine, smoky from a fire, or contains vermiculite. Dry, clean insulation can stay underneath your new R-49 top-up.
When is spray foam on the underside of the roof deck worth the extra cost?
Spraying open-cell or closed-cell foam onto the roof sheathing ($3.65 to $7.60/sq ft) is worth the premium when your HVAC air handler and ductwork sit inside the attic.
Does homeowners insurance cover wet attic insulation from a roof leak?
Yes, if the roof leak was caused by a sudden covered peril such as wind, hail, a fallen limb, or a winter ice dam.
How many inches of attic insulation do I need for R-49 or R-60?
For R-49, you need approximately 13.5 to 14.5 inches of settled blown-in cellulose, or 17.5 to 19 inches of blown-in fiberglass. For R-60, you need roughly 16.5 inches of cellulose or 21 to 22 inches of fiberglass.
Does insulation help in summer?
Yes. Attic insulation slows heat moving from a hot attic into the rooms below, which lowers cooling loads and keeps upstairs rooms more comfortable.
Related planning tools
Next steps for your estimate
Attic insulation & air sealing jobs rarely stop at one trade. These are the calculators people open next.
Soffit & fascia cost calculatorEnsure your eaves have perforated soffit intake vents to feed attic baffles.HVAC replacement cost calculatorSee how sealing and insulating your attic lets you downsize a new heat pump or AC.AC size & BTU calculatorRecalculate your whole-home cooling tonnage after upgrading to R-49.Water damage restoration calculatorEstimate wet insulation extraction and ceiling drywall repair after a leak.Roof replacement cost calculatorAdd ridge vents and air-seal from above while the roof decking is exposed.Weatherization & grants checkerCheck DOE Weatherization Assistance Program (WAP) eligibility for free insulation.
Key topics covered
Popular attic insulation searches answered on this page
Direct planning topics covered in the calculator and guide above.
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