Spray foam insulation cost in Huntsville, AL (as of October 2026)
Prices as of October 2026. Sources checked October 20 and 21, 2026.
Installed spray foam in Huntsville prices out at $0.60 to $1.60 per board foot for open-cell and $1.30 to $3.10 per board foot for closed-cell. Those are Angi's national ranges, updated September 9, 2026. Nobody we could find publishes a Huntsville-only rate, so every dollar figure on this page is our arithmetic on Angi's numbers, shown line by line.
Three Huntsville facts shape the bill. Alabama's energy code asks for only R-30 in an attic, well below the R-49 that ENERGY STAR suggests for a bare attic here. Huntsville Utilities sells TVA power, so the TVA EnergyRight rebates apply, at $300 per category. And three out of four Huntsville homes heat with electricity, so attic and duct losses land on the same power bill all year.
Huntsville at a glance
| Item | Huntsville figure |
|---|---|
| Climate zone (Madison County) | 3A, mixed-humid, in both the 2015 and 2021 IECC county lists |
| Attic minimum in the state energy code | R-30 |
| ENERGY STAR attic target, zone 3 | R-49 with no insulation; R-38 added over 3 to 4 inches |
| Electric utility | Huntsville Utilities, distributing TVA power |
| TVA EnergyRight rebates | $300 each: attic, walls, envelope air sealing, ducts |
| Homes heated with electricity | 75% (gas 23%) |
| Median year built | 1985; 44% before 1980, 20% in 2010 or later |
Sources: PNNL Building America Solution Center, climate zone by county; Alabama Administrative Code, r. 305-2-4, Appendix A (Table R402.1.2); ENERGY STAR, Recommended home insulation R-values; Huntsville Utilities, Home Energy Inspection Services; TVA EnergyRight, Home Insulation & Air Sealing; Census Bureau ACS 5-year data, 2020 to 2024.
Weather and the Huntsville service area
NOAA's 1991 to 2020 normals for Huntsville International Airport show about 2,107 cooling degree days and 2,831 heating degree days a year, roughly 62 days at 90°F or hotter, and 54.3 inches of rain. Heating degree days outnumber cooling degree days here, but not by a wide margin, so insulation earns its keep in both seasons.
Madison County and the neighboring Jackson, Marshall and Morgan counties all sit in zone 3A. Quote requests from these 19 ZIP codes match to our Huntsville area: 35670, 35741, 35748, 35750, 35754, 35759, 35760, 35763, 35775, 35801, 35802, 35803, 35805, 35806, 35808, 35810, 35811, 35816, 35896.
Sources: NOAA NCEI, U.S. Climate Normals 1991-2020, Huntsville International Airport station; PNNL Building America Solution Center, climate zone by county.
Installed price per board foot
| Measure | Open-cell | Closed-cell |
|---|---|---|
| Installed, per board foot (Angi, Sep 9, 2026) | $0.60 to $1.60 | $1.30 to $3.10 |
| Installed, per square foot at standard thickness (HomeGuide, Dec 1, 2025) | $1.50 to $3.50 | $3.00 to $5.00 |
| Job minimum many crews charge (HomeGuide) | $1,000 to $2,000 or more | |
| R-value per inch (Profoam product sheet) | R-3.6 | R-6.8 to R-7.1 |
A board foot is one square foot of foam one inch thick. To price any part of a house, divide the R-value you want by the R per inch to get the depth, multiply depth by square feet to get board feet, then multiply by the low and the high rate. On this page the closed-cell low figure uses R-7.1 per inch with the low rate, the high figure uses R-6.8 per inch with the high rate, and results are rounded to the closest hundred dollars. For a part-by-part comparison of the two foams, see open-cell vs closed-cell spray foam.
Sources: Angi, "How Much Does Spray Foam Insulation Cost? [2026 Data]" (updated Sep 9, 2026); HomeGuide, "How Much Does Spray Foam Insulation Cost? (2026)" (Dec 1, 2025); Profoam product price sheet.
Alabama's R-30 attic rule, and a code change that may come
Huntsville's Inspection Division lists the 2018 International Residential Code and the 2015 International Energy Conservation Code, which it labels the Alabama Energy Code. The U.S. Department of Energy shows Alabama's residential code as the 2015 IECC with state amendments, in force since October 1, 2016.
Alabama's amendments matter for foam. The state's insulation table in the Alabama Administrative Code sets these minimums for climate zone 3:
| Part of the house | Minimum | Open-cell depth | Closed-cell depth |
|---|---|---|---|
| Ceiling | R-30 | 8.3 in | 4.2 to 4.4 in |
| Wood-frame wall | R-13 | 3.6 in | 1.8 to 1.9 in |
| Floor | R-19 | 5.3 in | 2.7 to 2.8 in |
| Crawl space wall | R-5 continuous or R-13 cavity | not typical | about 0.7 in for R-5 |
The table governs new homes and permitted additions and alterations. How it applies to a retrofit in an existing attic is a question for the Inspection Division, not something we can settle here.
Change may be coming. A 2024 state law moved residential code adoption to the Alabama Home Builders Licensure Board, and an advisory council first met on February 13, 2025. The board's posted draft would make the 2024 IRC and 2024 IECC, with Alabama changes, the state's residential code beginning January 1, 2027. The draft caps new-home air leakage at 7.0 air changes per hour at 50 pascals, requires a balanced ventilation system when a house tests at 5.0 or tighter, and sets R-15 for attic knee walls in zone 3 under one alternative path. It also says local codes adopted and enforced before January 1, 2027 are not superseded, and the draft we read shows blank filing and effective dates. Treat it as a proposal, and ask the Inspection Division (256-427-5331) which edition your permit falls under.
Sources: City of Huntsville, Inspection Division, adopted codes; U.S. DOE Building Energy Codes Program, Alabama status; Alabama Administrative Code, r. 305-2-4, Appendix A (Table R402.1.2); Alabama Home Builders Licensure Board, statutory changes effective March 17, 2025; Alabama Home Builders Licensure Board, proposed Chapter 465-X-10, Alabama Residential Building Code (PDF, Sept. 2026).
Four Huntsville houses, priced
These dimensions are hypothetical, not Madison County averages.
1980s two-level home, 1,700 sq ft attic floor with soffit vents
To the R-30 code minimum, open-cell: 30 ÷ 3.6 = 8.3 inches; 1,700 × 8.3 = 14,167 board feet; $8,500 to $22,700
To R-30, closed-cell: 4.2 to 4.4 inches; 7,183 to 7,500 board feet; $9,300 to $23,300
To ENERGY STAR's R-49, open-cell: 13.6 inches; 23,139 board feet; $13,900 to $37,000
To R-49, closed-cell: 6.9 to 7.2 inches; 11,732 to 12,250 board feet; $15,300 to $38,000
Going from R-30 to R-49 on a floor this size adds roughly $5,000 to $15,000 in foam. If that stretches the budget, ask bidders to also price air sealing plus blown insulation on the same floor so you can compare.
Post-2010 home with the air handler upstairs in the attic, 2,000 sq ft base
Spraying the underside of the roof sheathing pulls the ductwork inside the insulated shell. With an 8/12 slope the sheathing comes to about 2,404 square feet (2,000 × 1.202).
6 inches open-cell, the roofline thickness on the Profoam sheet: 14,424 board feet, about R-21.6; $8,700 to $23,100
3 inches closed-cell, the Profoam sheet's roofline thickness: 7,212 board feet, about R-20.4 to R-21.3; $9,400 to $22,400
Deck foamed to R-30, open-cell: 8.3 inches; 20,033 board feet; $12,000 to $32,100
Deck foamed to R-30, closed-cell: 4.2 to 4.4 inches; 10,158 to 10,606 board feet; $13,200 to $32,900
Neither standard thickness reaches the R-30 ceiling value. Ask the Inspection Division whether a roof-sheathing retrofit has to meet R-30 before you settle on inches.
One-level home over a crawl space, 1,500 sq ft floor
Floor over the crawl space to R-19, open-cell: 5.3 inches; 7,917 board feet; $4,800 to $12,700
Same floor, closed-cell: 2.7 to 2.8 inches; 4,014 to 4,191 board feet; $5,200 to $13,000
Crawl walls instead: 156 feet around × 2.5 feet high = 390 sq ft; 1 inch closed-cell (R-6.8 to R-7.1): $500 to $1,200; 2 inches (R-13.6 to R-14.2): $1,000 to $2,400
One inch of closed-cell beats the R-5 continuous value for crawl walls, though a wall job this small may simply be billed at an installer's $1,000 to $2,000 minimum. Insulating the walls instead of the floor only works when the crawl space is closed off and the soil is covered with a vapor retarder, so get that scope written into the bid.
Bonus room over the garage
Rooms built over garages tend to have short knee walls and a floor over unconditioned space, two spots batts fill poorly. Here: 360 sq ft of knee wall plus a 320 sq ft floor.
Knee walls to R-15, closed-cell: 2.1 to 2.2 inches; 761 to 794 board feet; $1,000 to $2,500
Floor over the garage to R-19, closed-cell: 2.7 to 2.8 inches; 856 to 894 board feet; $1,100 to $2,800
Same floor, open-cell: 5.3 inches; 1,689 board feet; $1,000 to $2,700
Together that runs about $2,100 to $5,300, enough to get past most job minimums. Open-cell at R-15 needs 4.2 inches, more than a 2x4 knee wall has room for, so closed-cell wins there.
Sources: Angi, "How Much Does Spray Foam Insulation Cost? [2026 Data]" (updated Sep 9, 2026); HomeGuide, "How Much Does Spray Foam Insulation Cost? (2026)" (Dec 1, 2025); Profoam product price sheet; Alabama Administrative Code, r. 305-2-4, Appendix A (Table R402.1.2); ENERGY STAR, Recommended home insulation R-values.
What TVA and Huntsville Utilities pay
TVA EnergyRight lists four shell rebates at $300 apiece: attic insulation, wall insulation, envelope air sealing, and duct sealing and insulation. A Quality Contractor Network member performs the upgrade and submits it to TVA, which then sends you a code to collect the money. TVA requires the work to meet whatever TVA standards apply on the day it is installed.
| Example | Before rebates | Rebates that could apply | After rebates |
|---|---|---|---|
| Attic floor to R-30, open-cell | $8,500 to $22,700 | Attic $300 | $8,200 to $22,400 |
| Attic floor to R-30 plus air sealing | $8,500 to $22,700 | Attic + air sealing, $600 | $7,900 to $22,100 |
| Bonus room knee walls and floor | $2,100 to $5,300 | Walls $300, if it counts as wall insulation | $1,800 to $5,000 |
| All four categories in one project | varies | $1,200 | not priced here |
Two things the TVA pages leave open: whether spray foam is an eligible material for these rebates, and whether a home heated mainly by gas qualifies. About 23% of Huntsville homes heat with gas, and Huntsville Utilities is also the city's gas company. Ask the network contractor and TVA EnergyRight (855-237-2673) before you count the money.
Before any of that, Huntsville Utilities offers its own in-house home inspection: an attic insulation inspection, a review of ductwork and airflow, an air leak evaluation, an HVAC check and habit tips. The utility says there is no longer a fee. That is a cheap way to learn whether your attic needs foam, blown insulation or just sealing. Its natural gas incentives are for new gas heating systems and for new homes, not insulation, and its New Homes Program handles energy code checks for builders.
Sources: TVA EnergyRight, Home Insulation & Air Sealing; TVA EnergyRight, Residential Rebates; Huntsville Utilities, Home Energy Inspection Services; Huntsville Utilities, Energy Services; Huntsville Utilities, Natural Gas Incentives; Census Bureau ACS 5-year data, 2020 to 2024.
No federal credit for 2026 work
The IRS says the 25C Energy Efficient Home Improvement Credit applies to improvements made through December 31, 2025, so foam installed in 2026 gets no federal tax credit. Alabama's Home Energy Rebate status is tracked in our 2026 insulation rebate tracker.
Sources: IRS, Energy Efficient Home Improvement Credit.
Before you sign a Huntsville bid
Ask each installer to write down the square feet, the inches and the foam type for every area, then run those through our quote checker or the board-foot math above. Housing and climate data for the city are on the Huntsville spray foam page; Madison and Athens have their own pages because their utility split differs (Madison, Athens), and the rest of North Alabama is on our Alabama page. Ready to compare prices? Request up to 3 quotes.
Huntsville spray foam questions
What R-value does Huntsville require in an attic?
Huntsville lists the 2015 IECC as the Alabama Energy Code. Alabama's amended table sets an R-30 ceiling minimum for climate zone 3, which covers Madison County. ENERGY STAR recommends R-49 for an attic with no insulation, so code is the floor, not the target.
Will TVA pay a rebate on spray foam in Huntsville?
TVA lists $300 each for attic insulation, wall insulation, envelope air sealing and duct sealing and insulation, filed by a Quality Contractor Network member. Its pages do not say whether spray foam qualifies, so ask the contractor and TVA EnergyRight before you sign.
Does Huntsville Utilities offer a free energy audit?
Yes. Its in-house Home Energy Inspection Services survey covers attic insulation, ductwork and airflow, air leaks and the HVAC unit, and Huntsville Utilities says there is no longer a fee for it.
Is Alabama changing its residential energy code in 2027?
Maybe. The Home Builders Licensure Board has proposed a code based on the 2024 IRC and 2024 IECC that would apply beginning January 1, 2027, but the posted draft shows no filing or effective date, and it would not override local codes adopted before 2027.