Attic Insulation Cost Calculator
Attic insulation cost for a 1,500 sq ft attic runs about $6,606 in blown fiberglass or $5,169 in cellulose in Atlanta, taking a zone 3 ceiling from R-10 to R-49. The figure worth checking is not the price but the bag count: 52 bags of fiberglass. Federal rule 16 CFR 460.17 makes your installer put the coverage area, initial thickness, settled thickness, R-value and number of bags on your receipt. This calculator works out all five first.
Estimate the cost for your home
Estimated cost to insulate this attic
$7,174
typical · range $5,368 to $8,980 · 1,500 sq ft · adds R-50 toward R-60
Labour priced at national wages. Enter a ZIP code to price it for your area. 56% of this figure comes from modelled material prices — each line shows its own uncertainty.
Priced from bls.gov Aug 2026how every line is sourced
The one input that changes the answer for you.
The footprint you are insulating, usually close to the floor area of the storey below it.
Pick the description that fits where you live. It sets the R-value target.
The mid-Atlantic, Tennessee, Missouri, Kansas, and the coastal Pacific Northwest.
We aim at R-60 for this zone. That target is our estimate, in bands. What binds in your state is whichever edition of the energy code it has adopted, published by the Department of Energy at the state code adoption status page.
Sets the baffle count.
Only those not rated for insulation contact.
Multiplies the hours, never the material.
The usual case. Bags go up by hand, one at a time.
1 / 8
The figure above is already calculated. Each step just makes it more yours, and you can stop at any of them.
What federal law requires your receipt to say
The FTC R-Value Rule, 16 CFR 460.17, makes the installer hand you a dated receipt, and for loose fill it must show these five things. Here is what they should say for your attic.
- Coverage area
- 1,500 sq ft
- Initial installed thickness
- 20.4 in
- Minimum settled thickness
- 20.0 in
- R-value installed
- R-50
- Number of bags used
- 66
- Settled volume
- 2,500 cu ft
Count the empty bags before the crew leaves. At the 38 cubic feet per bag this material is rated at, reaching R-50 over 1,500 square feet takes about 66 bags. Fewer bags than that means less R-value than the invoice claims, and once the insulation is down nobody can see the difference.
| Line item | Qty | Cost | Source |
|---|---|---|---|
| Site protection and attic setup1 per job | 1lot | $45–$160 | estimated±56% |
| Crew mobilisation, setup and clean-up5 crew-hours × access factor (modelled) | 5hour | $229–$246 | sourced |
| Air sealing materials: caulk, foam, rigid covers and gasketsattic floor area, where air sealing is included and the boundary stays at the ceiling | 1,500sq ft | $270–$825 | estimated±51% |
| Air sealing labour0.008 h per sq ft × access factor (modelled) | 12hour | $550–$591 | sourced |
| Insulated and gasketed attic hatch or stair cover1 per job, wherever the insulated boundary stays at the ceiling | 1each | $70–$260 | estimated±58% |
| Sheet metal clearance dam around chimneys and appliance vents1 per job (modelled: most houses have at least one flue through the attic) | 1each | $35–$115 | estimated±53% |
| Fire-rated covers over recessed lights not rated for insulation contactone per non-IC-rated recessed light entered | 2each | $44–$136 | estimated±51% |
| Eave vent baffleseave length ÷ rafter spacing, two eaves, at the spacing entered | 59each | $71–$325 | estimated±64% |
| Retention dams at the access, the eaves and any whole-house fan1 per job wherever loose fill is blown | 1lot | $35–$120 | estimated±55% |
| R-value depth markersceil(attic sq ft ÷ 300), minimum 1, loose fill only | 5each | $6–$21 | estimated±56% |
| Fitting the baffles, dams, covers and hatch0.16 h/baffle + 0.65 h hatch + 0.75 h flue + 0.5 h/light + 0.75 h dams, × access factor | 12.6hour | $577–$620 | sourced |
| Blown fiberglass insulation, deliveredattic sq ft × inches needed ÷ 12, where inches = R to add ÷ 2.5 per inch | 2,500cubic ft | $1,750–$3,750 | estimated±36% |
| Insulation installation labourloose fill: (0.004 h/sq ft + cubic ft ÷ 130) × access; batts: 0.010 h/sq ft × access | 25.2hour | $1,157–$1,243 | sourced |
| Crew lead: set-out, depth verification and the installation receipt12% of crew hours + 0.5 h for the installation receipt (modelled) | 7.08hour | $528–$567 | sourced |
| Total | $5,368–$8,980 | ±25% |
Where these numbers come from
- The bag count, and why it is the number that matters
- Loose fill is invisible once it is down, and the classic way to be short-changed is to be blown fewer bags than the declared R-value needs. There is a federal defence and almost nobody publishes it. The FTC R-Value Rule at 16 CFR 460, Labeling and Advertising of Home Insulation requires the installer to give you a contract or receipt, and for loose fill that receipt must show the coverage area, the initial installed thickness, the minimum settled thickness, the R-value and the number of bags used. The law gives you the document; this page gives you the figures to hold it against. Retrieved 2026-08-22.
- The R-value target, and what actually binds in your state
- The target this calculator aims at is our own estimate, in broad bands: R-30 in zone 1, R-49 in zones 2 and 3, R-60 from zone 4 north. What binds legally is whichever edition of the energy code your state has adopted, and that is published by the Department of Energy at DOE Building Energy Codes Program, State Energy Code Methodology. The zone is chosen by you rather than derived from your ZIP code, because the ZIP lookup on this site resolves BLS wage areas and nothing else, and pretending otherwise would be inventing a chain that does not exist here. Retrieved 2026-08-22.
- The 30% federal tax credit expired on 31 December 2025
- Nothing is deducted from the figures above, and one dated fact explains why. The IRS states that the Energy Efficient Home Improvement Credit could be claimed “for improvements made through December 31, 2025” — IRS, Energy Efficient Home Improvement Credit — and ENERGY STAR, Insulation Tax Credit dates the insulation credit to products purchased and installed between 1 January 2023 and 31 December 2025. Cost guides still advertising 30% off insulation are describing a window that has closed. This is what those two federal pages say on the date shown, not tax advice. Retrieved 2026-08-22.
- Sealing a ceiling changes how the house breathes
- Air sealing is the line that makes the R-value perform, and it also makes the house tighter, which is a reason to look at ventilation and at any combustion appliance rather than a reason to skip it. Background on both: EPA, Introduction to Indoor Air Quality and CPSC, Carbon Monoxide Information Center, which is also why the sheet metal clearance dam around a flue is a line item here and not an afterthought. Retrieved 2026-08-22.
- Insulate first, size the equipment afterwards
- The order of these two jobs is what almost nobody respects. How many BTU a house needs depends on how much heat its envelope loses, so an attic insulated after the equipment is bought leaves you with equipment sized for the house you used to have. Do this one, then run the mini split installation cost figures. If the floor below is over a dirt crawl space, the same argument applies downwards, and the crawl space encapsulation cost is usually the other half of the envelope.
- Labour rates by area
- BLS Occupational Employment and Wage Statistics, May 2025, for insulation workers and construction supervisors in your metropolitan area. Retrieved 2026-08-20. Benefit load from BLS Employer Costs for Employee Compensation. Said plainly: this is the lowest-paid trade on this site, and a real insulation invoice usually bills above what that wage, loaded and marked up, produces.
- Material prices
- Modelled estimates, not sourced prices. No public, machine-readable source of US residential material prices exists, and we would rather say so than pretend otherwise. Each line carries its own uncertainty band. How we estimate them.
Contractor overhead and profit applied at 33–43% over direct cost. Data last reviewed 2026-08-22.
What this figure does not include
- Vermiculite insulation, and any asbestos work
- If the loose fill in your attic looks like small grey-brown or silver-gold pebbles rather than fluff, it is vermiculite, and vermiculite sold for insulation in the United States may contain asbestos. That is not an insulation job and it is not priced anywhere on this page. It requires testing first and then licensed, trained abatement contractors working under containment, and putting a low number against it would be worse than putting none. Do not disturb it, do not vacuum it, and get it assessed by a licensed asbestos professional before anyone goes into the attic.
- Attic ventilation upgrades: soffit vents and ridge vent
- Baffles keep an existing air channel open; they do not create ventilation where there is none. Plenty of 1970s houses with continuous aluminium soffit have nominal venting and very little real free area, and going to a deep insulation level is when that shows up. Adding soffit vents or a ridge vent is separate roofing work with its own price, and it is deliberately excluded rather than averaged in.
- Electrical work in the attic
- Three things routinely come up and none is priced here. Knob-and-tube wiring, which many jurisdictions prohibit burying under insulation, so the job stops until an electrician confirms it is dead or replaces it. Junction boxes, which have to stay accessible once the fill gets deeper than they are. And swapping non-IC recessed fixtures for airtight IC-rated units, which is sometimes better value than covering them. All three are an electrician’s work, not an insulator’s.
- Bath and dryer fans that vent into the attic
- They are supposed to discharge outdoors and a surprising number do not. It is almost always found during air sealing, because the crew is looking at exactly those penetrations. Rerouting a fan to a roof or gable termination is separate work, priced per fan.
- Duct sealing and duct insulation
- Ductwork running through a vented attic loses heat to a space that is, by design, at outdoor temperature. Sealing and insulating it is often better value per dollar than the last few inches of R-value, but it is a separate trade and a separate line.
- Roof leaks, rotten sheathing and existing mould
- Old insulation hides all three, and removal is how they get found. Nothing on this page fixes a roof, and insulating under one that leaks wastes the insulation as well as the money.
- Knee walls, bonus rooms and attic storage decking
- These figures cover the flat attic floor. A finished bonus room with sloped ceilings and knee walls is a different assembly at a different price per square foot, and raising a storage platform so the insulation can run underneath it is separate carpentry.
- A blower door test or a full home energy audit
- The right way to know how leaky a house is, and the right way to prove the air sealing worked. It is a separate service with its own price and it is not folded into these figures.
- Permit fees and inspections
- Some jurisdictions require a permit for insulation work, particularly where it is tied to a rebate or a code upgrade, and some require an inspection before the insulation is covered. Fees vary by jurisdiction with no national source, and are excluded rather than averaged into a figure that would be wrong everywhere.
- Tax credits, utility rebates and grant programmes
- Nothing is deducted from the figures on this page. One dated fact rather than a promise: the IRS states that the Energy Efficient Home Improvement Credit could be claimed "for improvements made through December 31, 2025", and ENERGY STAR states the insulation credit was "effective for products purchased and installed between January 1, 2023, and December 31, 2025". Cost guides that still advertise 30% off insulation are describing a window that has closed. Utility and state programmes are local, change constantly, and are not modelled. This is a statement of what those two federal pages say on the date shown, not tax advice; check your own position with the IRS or a tax professional.
Questions people actually ask
How many bags of blown insulation do I need for 1000 square feet?
About 44 bags of blown fiberglass or 80 of cellulose to reach an R-60 target over bare joists — and ⚠️ the reason this calculator works it out is that federal law says the number has to be on your receipt. 16 CFR 460.17 requires the installer to hand you a dated, signed receipt stating the coverage area, the initial installed thickness, the minimum settled thickness, the R-value and the number of bags used. The law gives you the right to the document; what it does not give you is anything to check it against. This is what to check it against. Cellulose takes roughly twice as many bags for the same R-value because a bag holds less of it, which is not a worse deal: it also needs about 30 per cent less depth. Twice the attic is 88 bags of fiberglass rather than double, because what is already up there counts.
How much does it cost to insulate a 1500 sq ft attic?
For a 1,500 square foot attic in Atlanta with four inches of blown fiberglass already down, taking it to the R-49 target we use for zone 3 comes to about $6,606 in blown fiberglass, $5,169 in cellulose or $6,200 in batts, with air sealing, baffles and an insulated hatch cover included in all three. Open-cell foam on the roof deck is a different job and prices at $14,566, because it insulates the sloped roof rather than the flat ceiling. The climate zone moves this more than the material does: the same attic in zone 1 is about $5,106 because the target drops to R-30, and in zone 4 it is $7,475 because the target rises to R-60.
Is adding attic insulation worth it?
That depends on how much is up there now, and this calculator is built so you can see it: enter the depth you measure and the target drops by whatever is already installed, so a ceiling at ten inches asks for far less material than bare joists. Two things are worth knowing before deciding. The federal 30 per cent insulation credit is gone: the IRS says the Energy Efficient Home Improvement Credit covers improvements made through December 31, 2025, and ENERGY STAR dates the insulation credit to the same window, so guides still advertising it are describing a closed door. And the order matters, because a tighter, better insulated ceiling changes the heating and cooling load the house needs. Insulate first, size the equipment afterwards.
What is the average cost to remove and replace attic insulation?
Removing four inches of old fiberglass and blowing a fresh R-49 over bare joists runs about $9,024 in Atlanta, against $6,606 for blowing over what is already there. The gap is not only the removal labour and the tipping fees: stripping the attic throws away the R-10 the old material was still delivering, so the new blanket has to be thicker to reach the same target. Most attics do not need removal at all. Dry, clean, settled insulation can be blown straight over. It earns its place when the material is wet, rodent-fouled or smoke-damaged, and that is a condition question rather than an age question.
What is the cheapest way to insulate my attic?
Blown cellulose, and it wins twice: it costs less per cubic foot and delivers more R-value per inch, so the same R-49 target needs 11.1 inches instead of 15.6, roughly 30 per cent less depth. In the Atlanta example it comes to $5,169 against $6,606 for blown fiberglass, on identical scope. Dropping the air sealing takes cellulose down to $3,874, and that is the one saving we would argue against, because sealing the ceiling is what decides whether the R-value on the invoice is the R-value the house gets. If you are doing it yourself, cellulose is also the material the rental blowers at the big-box stores are set up for.
Taken from Google’s “people also ask” results for this search on 22 August 2026, not invented.
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