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Cost to Insulate a House:
2026 Prices by Area
& Material

What it costs to insulate an attic, walls, crawl space or the whole house in 2026, what drives the price, where to spend first, and calculators for cost and payback.
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  • Existing insulation, if any
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$1,600–$8,000
What most homeowners spend on an insulation project
HomeGuide, 2026
$8k–$20k
Typical range to spray foam an entire house
HomeGuide, 2026
52%
Share of household energy used for space heating and air conditioning
EIA, RECS 2020
2025
Last year the 30% federal insulation tax credit (25C) applied
IRS

The cost to insulate a house runs from about $1,000 for topping up a small attic to $20,000 or more for spray foam in every wall, roof and crawl space. Where your house lands depends on which parts you insulate, whether the walls are open or finished, the material, and how much old insulation has to come out first. We sell spray foam, and in plenty of houses it is not the best value per dollar, so this guide prices every option side by side using 2026 cost data, shows where to spend first, and gives you two calculators: one estimates the whole-house cost, the other works out the payback.

Quick answer

HomeGuide's 2026 data puts most insulation projects at $1,600 to $8,000, and a full house at roughly $1.00 to $4.50 per square foot of area insulated: about $2,000 to $9,000 for a 2,000 sq ft home. Spray foam throughout runs $8,000 to $20,000. An attic top-up ($1,000 to $2,700) with air sealing is usually the best first dollar; walls cost more because they are closed in. The 30% federal 25C tax credit covered work placed in service through 2025 and is no longer available for 2026 projects, so check state and utility rebates instead.

What's in this guide
  1. 1Cost to insulate a house, by area
  2. 2Insulation cost by material
  3. 3Whole-house insulation cost calculator
  4. 4What drives the price
  5. 5Insulation payback estimator
  6. 6Where to spend first
  7. 7Tax credits and rebates in 2026
  8. 8FAQ
By area

Cost to insulate a house, by area

Very few houses get insulated all at once. Most owners do the attic one year, the crawl space or basement another, and the walls when the siding or drywall comes off. These are 2026 installed ranges for each part of the house. Click a header to sort.

AreaTypical installed costPer sq ftUsual materialNotes
Attic floor, blown-in$900–$3,600$0.90–$2.40Blown fiberglass or celluloseUsually the best return; air seal first
Attic, all types$1,000–$2,700variesBlown-in, battsHomeGuide's attic project range
Attic roof deck, spray foam$3,000–$8,000$1.50–$5.00Open- or closed-cell foamBrings ducts into conditioned space
Existing walls, drill-and-fill$1,900–$7,800$1.10–$3.70Dense-pack cellulose or fiberglassHoles drilled and patched
Exterior walls, spray foam$4,000–$10,000$1.50–$5.00Open- or closed-cell foamOpen walls: new build or gut remodel
Basement$600–$4,600$1.50–$2.50 (Angi)Rigid board, spray foam, battsRim joists matter most
Crawl space$500–$3,700variesBatts in floor or foam on wallsSpray foam crawl spaces $2,000–$4,000
Garage$600–$3,400$0.50–$1.25 (Angi)Batts, boardInsulate the shared wall and ceiling first
Old insulation removal$600–$1,200 typical attic$1.00–$2.00Vacuum removal and disposalBefore replacement or after damage
Sources: HomeGuide 2026 insulation, blown-in and spray foam cost guides; Angi insulation cost guide (basement and garage per sq ft); HomeAdvisor and Angi removal cost guides. Ranges are national; labor rates vary by region.

For the attic on its own, our attic insulation cost guide goes deeper, and the spray foam insulation cost guide breaks foam down by board foot. Walls are covered on our wall insulation page.

By material

Insulation cost by material

Installed price per square foot is the number most quotes are built on. It is not the whole story, because each material delivers a different R-value per inch (see our insulation R-value chart), and spray foam also air seals, which batts and loose-fill do not.

MaterialInstalled per sq ftMaterial onlyAir seals?Best use
Radiant barrier$0.30–$2.00n/aNoHot-climate attics with ducts (not a substitute for insulation)
Fiberglass or mineral wool batts$0.80–$2.60Fiberglass $0.30–$1.30; mineral wool $1.00–$2.50NoOpen walls, floors, new construction
Blown-in fiberglass or cellulose$1.00–$2.80Cellulose $0.30–$1.80Dense-pack slows airAttic floors, existing closed walls
Rigid foam board$1.20–$3.70Polystyrene $0.25–$0.50 (Angi)If seams are sealedBasement walls, exterior sheathing, slabs
Open-cell spray foam$1.50–$3.50$0.30–$0.50 per board footYesRoof decks, interior walls, sound control
Closed-cell spray foam$3.00–$5.00$0.90–$1.00 per board footYes, plus vapor retarderRim joists, crawl spaces, basements, metal buildings
Sources: HomeGuide 2026 insulation cost (installed and material ranges) and spray foam cost (open- and closed-cell installed); Angi (polystyrene material). A board foot is 1 sq ft at 1 inch thick.
Calculator

Whole-house insulation cost calculator

Enter your home's size, pick which areas to insulate and the material for each, and the calculator estimates the area of each surface and prices it with the 2026 per-square-foot ranges above.

Project estimate

What will it cost to insulate my house?

Our area assumptions: square footprint, 8 ft walls per story, 15% of wall area for windows and doors, roof deck 15% larger than the attic floor, 3 ft crawl space walls. Prices: HomeGuide 2026 installed ranges per sq ft. Get quotes for real numbers.

Extras
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Estimated total
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Per sq ft of home
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Area insulated

Pricing

What drives the cost to insulate a house

Two houses of the same size can be quoted thousands of dollars apart. These are the line items that make the difference:

Access

Open or closed walls

Open stud bays take batts or spray foam at the low end of the range. Finished walls mean drilling, dense-packing and patching at $1.10 to $3.70 per sq ft, or waiting until the siding or drywall comes off.

Removal

What has to come out first

Removing old insulation adds $1.00 to $2.00 per sq ft. Rodent-contaminated, wet or moldy material costs more, and vermiculite that may contain asbestos needs an abatement contractor. Our attic insulation removal guide covers when it is needed.

Target

R-value and depth

Going from R-38 to R-60 in an attic adds material, not much labor. In walls and roof decks, the cavity depth caps what you can fit, which pushes you toward higher-R materials that cost more per inch.

Labor

Region and job size

Angi reports labor at $40 to $80 per hour, and HomeGuide puts installation labor at $0.50 to $1.70 per sq ft. Spray foam contractors often set a minimum charge of $1,000 to $2,000, so small foam jobs cost more per foot.

Prep

Air sealing and baffles

DOE says to seal air leaks and make repairs before insulating. Good quotes include sealing top plates, penetrations and the attic hatch, plus baffles at the eaves. Cheap quotes often skip them.

Code items

Barriers and permits

Spray foam in living spaces and many attics needs a thermal or ignition barrier under building code, and some jurisdictions require permits for insulation work. Ask whether both are in the price.

Calculator

Insulation payback estimator

ENERGY STAR estimates that sealing and insulating can save up to 10% on annual energy bills. Enter your yearly energy spending, your project cost and any rebate, and this tool shows the payback at the savings rate you choose.

Payback

How long until it pays for itself?

Annual savings = energy bill × savings rate. Simple payback = (cost − rebates) ÷ annual savings. The heating and cooling share uses EIA's 52% national average. Energy prices are held flat.

Gas plus electric for a year
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Saved per year
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Simple payback
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Net over your stay
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Your heating and cooling share

The 15% chip is our illustration for drafty, under-insulated houses, not a published average; your savings depend on how much insulation you have now and how leaky the house is. Comfort, quieter rooms and smaller HVAC loads do not show up in a payback number but often matter more to the people living there.

Order of work

Where to spend first

  1. Air seal and top up the attic

    DOE's rule of thumb: if the attic has less than about R-30, roughly 10 to 13 inches, you could probably benefit from more. It is the cheapest area to reach and usually returns the most per dollar.

  2. Seal and insulate ducts in unconditioned space

    DOE recommends sealing and insulating ductwork that runs through attics, crawl spaces or garages. Leaky ducts there waste conditioned air before it reaches a room.

  3. Rim joists, crawl space and basement

    Rim joists are small, leaky and easy to reach. Closed-cell foam air seals and insulates them in one pass. Our crawl space encapsulation guide covers the bigger crawl space job, and the pipe insulation guide covers the supply lines down there.

  4. Walls, when the siding comes off

    ENERGY STAR suggests drilling and blowing insulation into empty wall cavities when re-siding, and adding R-5 to R-10 of insulative sheathing under new siding in zones 3 through 8.

  5. Radiant barrier only where it fits

    In hot, sunny climates with ducts in the attic, a radiant barrier can trim cooling costs. Elsewhere it is a low priority; our radiant barrier guide explains why.

Incentives

Tax credits and rebates in 2026

The federal Energy Efficient Home Improvement Credit (25C) paid 30% of qualifying insulation and air sealing material costs, up to $1,200 a year. The IRS lists it as available for qualifying property placed in service from January 1, 2023 through the end of 2025. Insulation installed in 2026 does not qualify, and some contractors are still quoting it, so ask.

What is left is local. Many states run Home Energy Rebate programs funded through DOE, each with its own eligibility rules and application steps, and many utilities offer insulation and air sealing rebates or free energy audits. Check your state energy office and your utility's website before signing a contract, because some programs require pre-approval or a participating contractor.

Before you signUnder the FTC R-value Rule, your installer must give you a receipt with the coverage area, thickness and R-value installed, and for loose-fill, the initial and settled thickness and number of bags. Rebate programs often ask for exactly that paperwork.
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FAQ

Cost to insulate a house questions

How much does it cost to insulate a 2,000 sq ft house?

HomeGuide's 2026 data puts a 2,000 sq ft insulation job at about $2,000 to $9,000. Spray foam throughout a whole house runs about $8,000 to $20,000. Which areas you include and whether the walls are open make the biggest difference.

What is the cheapest way to insulate a house?

Air sealing plus blown-in insulation in the attic. Blown-in attic insulation costs about $0.90 to $2.40 per sq ft installed, and the attic is usually the easiest place to add a lot of R-value.

How much does it cost to insulate existing walls?

Drill-and-fill blown-in wall insulation runs about $1.10 to $3.70 per sq ft, or roughly $1,900 to $7,800 for a typical house, according to HomeGuide. Spray foam is only practical in walls that are open.

Is spray foam worth the extra cost?

It is in places where depth is tight or air sealing matters most: roof decks, rim joists, crawl space walls, basements and metal buildings. On an open attic floor, blown-in insulation usually gives more R-value per dollar.

Is there a tax credit for insulation in 2026?

Not at the federal level. The IRS lists the 25C Energy Efficient Home Improvement Credit as covering qualifying property placed in service through 2025. Check your state energy office and utility for current rebates.

How much can insulation save on energy bills?

ENERGY STAR estimates that sealing air leaks and adding insulation can save up to 10% on annual energy bills. Heating and air conditioning make up 52% of household energy use nationally, according to EIA, so homes with high heating or cooling bills tend to see more.

Do I need to remove old insulation before adding new?

Usually not. Dry, clean insulation can stay, and new insulation goes on top. Removal makes sense when the old material is wet, moldy, rodent-contaminated or smoke-damaged, or when you are switching to spray foam on the attic floor. Removal typically adds $1.00 to $2.00 per sq ft.

How long does it take to insulate a house?

An attic top-up is often done in a day. Drill-and-fill walls or spray foam throughout can take several days, and spray foam usually needs the house vacated for a period set by the manufacturer while it cures and ventilates.

AT
Written by the ArmorThane technical team. We have manufactured spray foam and protective coatings since 1989 and train the applicators who install them. Prices are third-party 2026 national ranges, not ArmorThane pricing. Updated October 2026.

Sources

  1. HomeGuide, insulation cost 2026: homeguide.com/costs/insulation-cost
  2. HomeGuide, spray foam insulation cost: homeguide.com/costs/spray-foam-insulation-cost
  3. HomeGuide, blown-in insulation cost: homeguide.com/costs/blown-in-insulation-cost
  4. Angi, insulation cost: angi.com
  5. HomeAdvisor, insulation removal cost: homeadvisor.com
  6. IRS, Energy Efficient Home Improvement Credit: irs.gov
  7. U.S. Energy Information Administration, use of energy in homes (RECS 2020): eia.gov
  8. ENERGY STAR, seal and insulate: energystar.gov
  9. ENERGY STAR, recommended insulation levels for existing homes: energystar.gov
  10. U.S. Department of Energy, Where to Insulate in a Home: energy.gov
  11. U.S. Department of Energy, Home Energy Rebates: energy.gov/save/rebates
  12. Federal Trade Commission R-value Rule, 16 CFR Part 460: ecfr.gov

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