Insulation Calculator
Estimate insulation costs by type: fiberglass, blown-in, spray foam. R-value recommendations with regional pricing and labor. Free, no signup.
What insulating a house costs: worked national example
A 40 × 30 ft footprint (1,200 sq ft) with 8 ft walls, insulated to R-38 in Blown-in Cellulose, at national baseline pricing — not adjusted for any region. Enter your own dimensions below for a figure matched to your project and ZIP code.
That is 1,200 sq ft of ceiling plus 952 sq ft of wall, after the estimate deducts 15% of the gross wall area for doors and windows — about 60 bags of Blown-in Cellulose at a settled depth of 10.8".
Installed cost by house size and R-value
| Footprint | R-13 | R-19 | R-30 | R-38 | R-49 | R-60 |
|---|---|---|---|---|---|---|
| 20 × 20 ft944 sq ft insulated | $2,690 | $3,304 | $4,390 | $5,192 | $6,278 | $7,363 |
| 24 × 30 ft1,454 sq ft insulated | $4,145 | $5,090 | $6,763 | $7,999 | $9,672 | $11,344 |
| 30 × 30 ft1,716 sq ft insulated | $4,891 | $6,006 | $7,979 | $9,438 | $11,411 | $13,385 |
| 40 × 30 ft2,152 sq ft insulated | $6,133 | $7,532 | $10,007 | $11,836 | $14,311 | $16,786 |
| 40 × 40 ft2,688 sq ft insulated | $7,661 | $9,408 | $12,499 | $14,784 | $17,875 | $20,966 |
| 50 × 40 ft3,224 sq ft insulated | $9,188 | $11,284 | $14,992 | $17,732 | $21,440 | $25,147 |
For Homeowners: Get a quick cost range with just a few measurements. Perfect for budgeting and comparing contractor quotes.
Quick Mode: Get a fast estimate with basic dimensions. Perfect for homeowners and initial budgeting.
Assumptions & Sources
Assumptions
- Material pricing: Based on 2025 national averages from major retailers and insulation contractors. Spray foam pricing from certified installer quotes.
- Labor rates: Labor is billed as a flat rate per square foot of insulated surface, set by material, and is already inside every per-square-foot figure on this page. It is not a multiplier of material cost — that model was removed from the engine because it inflated premium materials disproportionately.
- Wall area deduction: 15% subtracted from gross wall area to account for doors, windows, and framing members.
- Energy savings: Estimated at $0.15 per square foot of insulated surface per year, based on DOE averages. Actual savings depend on climate zone, existing insulation, and HVAC efficiency.
- Material in the free estimate: Quick mode prices Blown-in Cellulose — the material selector is a Professional-mode input, so every figure on this page is one a visitor can reproduce without leaving the free calculator.
- Regional multiplier: ZIP-code-based adjustment using BLS regional wage data and published construction cost indices applied to both materials and labor.
Last updated: August 2026
Pro Tips from the Field
- R-value by climate zone: Zone 1 (Miami) needs R-13 walls / R-30 attic. Zone 6 (Minneapolis) needs R-20 walls / R-49 attic. Look up your zone and match code minimum at bare minimum.
- Vapor barrier placement: Always on the warm side. Cold climates = interior face. Hot-humid climates (Gulf Coast) = exterior. Get this wrong and you trap moisture in the wall cavity — mold and rot within 2-3 years.
- Don't stack batts to cheat R-value: Two layers of R-19 crammed into a 2×6 cavity doesn't give R-38 — compression kills performance. Use the right product for the cavity depth.
- Attic ventilation matters equally: Sealing your attic tight without proper soffit-to-ridge ventilation creates a moisture trap. Install baffles at every rafter bay to keep air moving above the insulation.
- Air seal first, insulate second: An afternoon of caulking and canned foam around penetrations (wire runs, plumbing stacks, recessed light cans, the attic hatch) outperforms a far larger spend on insulation laid over leaky framing. This calculator does not price air sealing, and it is the highest-return energy work in the building. Do it before the blower arrives — once the attic is full you cannot find the holes.
Related Calculators
- Drywall Calculator — Estimate drywall sheets, mud, and tape if you're re-closing walls after insulation work.
- HVAC Calculator — Calculate heating and cooling system costs — proper insulation reduces your required HVAC capacity and operating costs.
- Roofing Calculator — Estimate roofing costs if your attic insulation project reveals roof deck issues that need addressing first.
How Insulation Estimates Are Built
Insulation is priced by the square foot of surface it covers, and the first thing to get straight is which surface. A 1,200 square foot floor plan is not 1,200 square feet of insulation. On the 40 x 30 ft reference house used throughout this page the free estimate bills 2,152 square feet — the ceiling plus the wall area, less 15% for doors and windows. Every per-square-foot figure below is against that insulated area, not against the floor.
The estimate is all-in. The rate covers material, a vapor barrier and installation labor, which is why it lands well above a bag price at the home center. At R-38 in Blown-in Cellulose this calculator returns $5.50 per square foot typical, in a band of $4.15 to $7.10. The band is not a guess about your contractor: it is the spread between a straightforward open attic and a job with poor access, tight bays and a lot of cutting.
R-value is the lever that moves the number most, and it moves it close to linearly — doubling the R roughly doubles the material bill, because you are buying twice as much of the same stuff. What does not double is the saving. Heat loss falls with 1/R, so the step from R-13 to R-19 buys far more comfort per dollar than the step from R-49 to R-60. Hit the code minimum for your climate zone first, then decide whether the next step up earns its keep.
One thing this calculator does not price is air sealing. Caulking and foaming the penetrations through the ceiling plane — wire runs, plumbing stacks, recessed light cans, the attic hatch — is a separate job, and on a leaky house it will outperform the insulation laid over it. Do it first, and do it before the blower arrives.
Insulation Cost Per Square Foot by R-Value
This is the axis the free calculator actually gives you. Each row is a separate execution of the estimate on the 40 x 30 ft reference house at national baseline pricing, divided by its 2,152 square feet of insulated surface. The settled-depth column is the engine's own figure for Blown-in Cellulose — check it against your joist depth before committing to a target, because blowing past the available depth compresses the material and loses the R-value you paid for.
| R-Value | Settled depth | Low | Typical | High | 40 x 30 ft house |
|---|---|---|---|---|---|
| R-13 | 3.7" | $2.15/sq ft | $2.85/sq ft | $3.65/sq ft | $6,133 |
| R-19 | 5.4" | $2.65/sq ft | $3.50/sq ft | $4.50/sq ft | $7,532 |
| R-30 | 8.6" | $3.50/sq ft | $4.65/sq ft | $6.00/sq ft | $10,007 |
| R-38 | 10.8" | $4.15/sq ft | $5.50/sq ft | $7.10/sq ft | $11,836 |
| R-49 | 14" | $5.05/sq ft | $6.65/sq ft | $8.60/sq ft | $14,311 |
| R-60 | 17" | $5.90/sq ft | $7.80/sq ft | $10.10/sq ft | $16,786 |
The free estimate prices Blown-in Cellulose, and only Blown-in Cellulose. Material selection — fiberglass batts, blown-in fiberglass, mineral wool, rigid board, open- and closed-cell spray foam — sits in Professional mode, so the figures above are the ones you can reproduce in the calculator on this page without changing anything else. We publish what the free tool returns rather than a range nobody can get back to.
Where the Square Footage Comes From
Wall height is the second free input that moves the number, and it is why two houses with the same floor plan get different estimates. This table is the arithmetic the calculator performs on the 40 x 30 ft reference footprint: the perimeter times the wall height, less 15% for openings, plus the ceiling.
| Wall height | Gross wall | Net wall (less openings) | Ceiling | Insulated area | Installed cost |
|---|---|---|---|---|---|
| 8 ft | 1,120 sq ft | 952 sq ft | 1,200 sq ft | 2,152 sq ft | $11,836 |
| 9 ft | 1,260 sq ft | 1,071 sq ft | 1,200 sq ft | 2,271 sq ft | $12,490 |
| 10 ft | 1,400 sq ft | 1,190 sq ft | 1,200 sq ft | 2,390 sq ft | $13,145 |
| 12 ft | 1,680 sq ft | 1,428 sq ft | 1,200 sq ft | 2,628 sq ft | $14,454 |
The 15% deduction is a blanket allowance, not a takeoff of your elevations. If your house is mostly glass on one side you are over-billed; if it is a windowless gable end, under-billed. For an attic-only job — much the most common insulation project — price the attic on its own by entering the attic footprint and reading the ceiling column, rather than entering the whole house and mentally subtracting the walls.
Insulation Cost by Metro Area
Insulation is a labor-heavy trade, and labor is what actually varies between markets: the material itself comes off the same handful of mills wherever you are. These are the complete regional factors this calculator applies — not a selection. Type the ZIP in the second column into the ZIP field above and the calculator will price your own house at that factor. The cost column is the same 40 x 30 ft reference house used throughout this page, so the rows are comparable to each other and to the national $11,836 above.
| Metro area | ZIP to enter | Factor | Reference house | Per sq ft |
|---|---|---|---|---|
| San Francisco Bay Area, CA | 94102 | 1.70× | $20,121 | $9.35 |
| New York City, NY | 10001 | 1.68× | $19,884 | $9.24 |
| Seattle, WA | 98101 | 1.55× | $18,346 | $8.53 |
| Boston, MA | 02108 | 1.52× | $17,991 | $8.36 |
| Los Angeles, CA | 90001 | 1.45× | $17,162 | $7.97 |
| Hartford, CT | 06101 | 1.40× | $16,570 | $7.70 |
| San Diego, CA | 92101 | 1.38× | $16,334 | $7.59 |
| Chicago, IL | 60601 | 1.32× | $15,624 | $7.26 |
| Philadelphia, PA | 19019 | 1.28× | $15,150 | $7.04 |
| Portland, OR | 97201 | 1.22× | $14,440 | $6.71 |
| Denver, CO | 80201 | 1.18× | $13,966 | $6.49 |
| Minneapolis-St. Paul, MN | 55401 | 1.14× | $13,493 | $6.27 |
| Miami, FL | 33101 | 1.12× | $13,256 | $6.16 |
| Las Vegas, NV | 89101 | 1.08× | $12,783 | $5.94 |
| Richmond, VA | 23173 | 1.08× | $12,783 | $5.94 |
| Austin, TX | 78701 | 1.05× | $12,428 | $5.78 |
| Detroit, MI | 48201 | 1.05× | $12,428 | $5.78 |
| Milwaukee, WI | 53201 | 1.04× | $12,309 | $5.72 |
| Salt Lake City, UT | 84101 | 1.03× | $12,191 | $5.66 |
| Atlanta, GA | 30301 | 1.02× | $12,073 | $5.61 |
| Phoenix, AZ | 85001 | 0.99× | $11,718 | $5.45 |
| Dallas-Fort Worth, TX | 75201 | 0.98× | $11,599 | $5.39 |
| Raleigh-Durham, NC | 27513 | 0.96× | $11,363 | $5.28 |
| Houston, TX | 77001 | 0.95× | $11,244 | $5.22 |
| Kansas City, MO | 64101 | 0.95× | $11,244 | $5.22 |
| Nashville, TN | 37201 | 0.93× | $11,007 | $5.11 |
| Columbus, OH | 43001 | 0.92× | $10,889 | $5.06 |
| Indianapolis, IN | 46201 | 0.90× | $10,652 | $4.95 |
The factor is applied to the whole estimate rather than to the material alone, which is the right behaviour for a trade where the crew is most of the bill. If your ZIP is not in this list the calculator prices at the national baseline rather than guessing at a factor it does not have.
Frequently Asked Questions
Construction Cost Estimation FAQs
A 40 by 30 foot footprint with 8 foot walls works out to 2,152 square feet of insulated surface — 1,200 square feet of ceiling plus 952 square feet of wall, once 15 percent is deducted for doors and windows. At R-38 in Blown-in Cellulose this calculator returns $11,836 installed at national baseline pricing, in a band of $8,931 to $15,279, which is $5.50 per square foot of insulated surface. Enter your ZIP code for a regionally adjusted figure.
The free estimate prices Blown-in Cellulose from $2.15 per square foot at R-13 up to $10.10 per square foot at R-60, installed, at national baseline pricing. At R-38 the band is $4.15 to $7.10. Watch the unit: that is per square foot of insulated surface, not per square foot of floor. On the 40 x 30 ft reference house those are very different numbers — 2,152 square feet of surface over a 1,200 square foot floor.
On the 40 x 30 ft reference house this calculator puts R-38 at $11,836 and R-60 at $16,786 — a difference of $4,950, or $2.30 per square foot. The physics work against you as you climb. Each R-point costs about the same to add, but heat loss falls with 1 over R, so each point saves less than the one before it. Above the code minimum for your climate zone the payback period stretches out quickly, which is why energy codes stop where they do rather than specifying the thickest product on the shelf.
In Blown-in Cellulose, R-38 is a settled depth of 10.8". The full ladder this calculator prices runs R-13 at 3.7", R-19 at 5.4", R-30 at 8.6", R-38 at 10.8", R-49 at 14", R-60 at 17". Depth matters for more than price: an attic hatch, a set of baffles or a rafter bay only has so much room, and blowing past that depth compresses the material and loses the R-value you paid for. Measure the joist depth before you pick a target.
Up to a point. This calculator publishes a DIY figure while the job stays small enough that a rental blower and a weekend still make sense. On a 30 by 30 foot footprint — 1,716 square feet of insulated surface — that is $8,294 in materials and blower rental against $9,438 to have it installed, and roughly 18 hours of work. Past that size the estimate stops offering a DIY number, because the rental-day arithmetic stops working and the crawling gets genuinely hazardous. Wear a respirator rather than a dust mask, work off planks laid across the joists, and never step into the insulation — the ceiling below is drywall, not a floor.
This calculator carries 28 metro factors, and they move the whole estimate rather than just the material. The same 40 x 30 ft reference house at R-38 runs $20,121 in San Francisco Bay Area, CA at 1.70x and $10,652 in Indianapolis, IN at 0.90x, against $11,836 at the national baseline. The table further down this page lists every metro with a ZIP you can type into the calculator. If your ZIP is not in that list the estimate prices at the national baseline rather than guessing.
Required R-values depend on your climate zone and on where in the building the insulation goes. Attics generally need R-38 to R-60, exterior walls R-13 to R-21, and floors over unconditioned space R-25 to R-30. Those are code minimums rather than targets. In zone 5 and above, one step past the attic minimum is usually the cheapest efficiency you can buy, because the attic is where the biggest temperature difference sits and where the insulation is easiest to add.
Insulation Calculator by State
Get insulation cost estimates with state-specific regional pricing: