Spray foam insulation in Decatur, AL: get up to 3 quotes from vetted local installers
Request free quotes from up to three vetted spray foam installers serving Decatur and nearby Morgan County. Below: what your climate zone means for open vs closed cell, how much insulation to ask for, Alabama's energy code, and the rebates we could verify.
- Climate zone: 3A (2021 IECC)
- Attic target: R-49 (ENERGY STAR, uninsulated attic)
- State code: 2015 IECC with Alabama amendments
- Utility rebates we verified: TVA EnergyRight
- Federal 25C credit: ended for 2026 installs
Facts last checked October 16, 2026. Sources are linked in each section.
Where we match quotes from this page
Requests from Decatur and ZIP codes whose center is within about 20 miles of it go to our Decatur, AL partner installers (6 ZIP codes): 35601, 35603, 35640, 35649, 35671, 35673. Outside these? Send the form anyway and we'll tell you if we can't match you.
Climate zone 3A: what it means for spray foam
Decatur's central point is in Morgan County, which the 2021 IECC county map assigns to climate zone 3A (mixed-humid in DOE's Building America terms). Zone 3A is a moist ("A") zone, which drives the vapor and R-value rules below.
Other counties within our Decatur service radius: Lawrence County (3A), Limestone County (3A). All are zone 3A too.
Source: PNNL-33270, Guide to Determining Climate Zone by County (IECC 2021).
Open cell vs closed cell in Decatur, AL
Attic roofline: in climate zones 1–3 an unvented ("sealed") attic with open-cell foam sprayed under the roof deck is a common way to bring attic ductwork and air handlers inside the insulated envelope. The International Residential Code (Section R806.5) allows unvented attics with air-impermeable insulation such as spray foam; for a hybrid "flash-and-fill" assembly the foam layer at the deck must be at least R-5 in zone 3A.
Humidity: in a mixed-humid climate, a sealed attic becomes part of the conditioned house. Ask how the installer and your HVAC contractor will handle attic humidity (for example a small supply-air connection or dehumidification).
Closed cell earns its higher price where you need a vapor retarder or water resistance: crawlspace walls, rim joists, below-grade walls.
Metal buildings, pole barns and shops
For uninsulated metal roofs and walls, closed-cell foam sprayed directly on the panels is used both as insulation and as a vapor retarder to stop condensation from forming and dripping on the underside of the metal. When you request quotes, choose "Metal building / pole barn" and give the building's footprint and wall height; ask each installer for foam type, thickness, and whether a thermal or ignition barrier coating is required for how the building will be used. We don't have data on how common these buildings are around Decatur, so we won't guess.
How much insulation to ask for
| Where | ENERGY STAR recommendation for zone 3A |
|---|---|
| Attic, uninsulated | R-49 |
| Attic with 3–4" of existing insulation | add R-38 |
| Floor over unconditioned crawlspace/basement | R-19 |
| Basement or crawlspace walls | R-5 continuous or R-13 cavity |
| Exterior walls (when re-siding) | add R-5 insulative wall sheathing beneath new siding |
To reach R-49 with foam alone you'd need roughly 13.2–14.0" of open cell (about R-3.5 to R-3.7 per inch) or 7.0–9.8" of closed cell (about R-5 to R-7 per inch). Many roofline spray foam jobs are installed thinner than that and justified through the code's performance path or the unvented-attic rules, so ask every installer to write the foam type, thickness and resulting R-value on the quote and explain how it meets your local code.
Source: ENERGY STAR, Recommended Home Insulation R-Values (based on 2021 IECC). ENERGY STAR's figures are recommendations for existing homes; your local code sets the legal minimum for new work.
Alabama energy code
2015 IECC with Alabama amendments, effective October 1, 2016. NAHB notes that adoption authority for the Alabama Residential Building Code moved to a new state body effective October 1, 2024, and an update had not yet been adopted as of May 2026.
Source: NAHB, "Residential Provisions of the IECC: State Adoption Status" (current as of May 2026); official state status at DOE Building Energy Codes Program.
Homes in Decatur, AL
Census figures for Decatur city (ACS 2020–2024 5-year estimates): about 25,467 housing units, a median year built of 1977, 56% built before 1980 and 6% built in 2010 or later. 70% are single-family detached homes and 2% are mobile/manufactured homes. 63% of occupied homes are owner-occupied, with a median owner-reported home value of $210,200.
- With 56% of homes built before 1980, many attics here predate modern energy codes. Older attics often need old insulation removed or air-sealed first, and knob-and-tube wiring must be checked before any insulation covers it. Ask whether removal and prep are in the price.
- 72% of homes heat with electricity (furnaces, heat pumps or baseboard). Several utility insulation rebates are aimed at electric-heat or central-A/C customers, so check the programs below.
Rebates and incentives for Decatur, AL
Utility programs that may apply, depending on which utility serves your address:
TVA EnergyRight (through participating local power companies)
Rebates of up to $300 each for attic insulation, wall insulation, envelope air sealing, and duct sealing/insulation when a TVA Quality Contractor Network member does the work. Eligibility depends on whether your local power company participates.
Read on the program's own page October 16, 2026. Programs change; confirm before you sign.
Alabama Power
Alabama Power's rebate page listed no attic insulation rebate when we checked (it lists heat pump, water heater, thermostat and EV charger offers). Co-op and municipal customers should ask their own utility.
Read on the program's own page October 16, 2026. Programs change; confirm before you sign.
Alabama state Home Energy Rebates
Not yet launched Inflation Reduction Act Home Energy Rebates Program
Electrification/appliance rebates (HEAR): "This program is under development. The date in which eligible households will be able to access these rebates has not been determined."
Whole-home efficiency rebates (HOMES/HER): "This program is under development. The date in which eligible households will be able to access these rebates has not been determined."
Official source: ADECA. Status text compiled via referencesource.org, last checked by them August 25, 2026. Full Alabama rebate page →
What spray foam costs (national published ranges)
We don't have enough local quotes for Decatur, AL to publish local prices, and we won't make them up. These national ranges are a starting point; your installers' quotes are what count.
| Example job (typical thickness) | Estimated installed range |
|---|---|
| 1,000 sq ft attic roofline, open cell (6") | $3,600–$9,600 |
| 1,000 sq ft attic roofline, closed cell (3") | $3,900–$9,300 |
| 1,500 sq ft walls, open cell (3.5") | $3,150–$8,400 |
| 1,500 sq ft walls, closed cell (2") | $3,900–$9,300 |
| 200 sq ft rim joists, closed cell (2") | $520–$1,240 |
Board feet × Angi's 2026 installed price per board foot. Angi reports a national average spray foam project of $2,888 (typical $1,455–$4,337). Check a quote you already have →
Questions to ask each installer
- Foam type, brand, thickness and resulting R-value for each area, in writing.
- Which climate zone and code edition they're designing to.
- Whether removal of old insulation, air sealing, and any required ignition/thermal barrier coating are included.
- Whether they participate in TVA EnergyRight (through participating local power companies) or the other programs above, and who files the paperwork.
- Whether they'll do (or coordinate) combustion safety testing if you have gas appliances.
FAQ
What climate zone is Decatur, AL in?
Morgan County is IECC 2021 climate zone 3A, per PNNL's county list (PNNL-33270).
Should I use open-cell or closed-cell spray foam in Decatur, AL?
For attic rooflines in zone 3A, open cell is common and code-permitted in unvented attics; closed cell is worth the premium for crawlspace walls, rim joists and metal buildings.
How much attic insulation do homes in Decatur, AL need?
ENERGY STAR recommends R-49 for an uninsulated attic in zone 3A (or adding R-38 on top of 3–4 inches of existing insulation). Alabama's code: 2015 IECC with Alabama amendments.
Are there spray foam or insulation rebates in Decatur, AL in 2026?
The federal 25C tax credit does not apply to insulation installed after December 31, 2025. Utility programs that may apply, depending on which utility serves your address: TVA EnergyRight (through participating local power companies); Alabama Power. Alabama's state Home Energy Rebate program status: Not yet launched.
How much does spray foam cost in Decatur, AL?
We don't publish local prices until we have enough real local quotes. National published ranges are about $0.60–$1.60 per board foot for open cell and $1.30–$3.10 for closed cell, installed (Angi, 2026), and many companies have a $1,000–$2,000 minimum.
How does requesting quotes work?
Fill in the form once. We pass your request to up to three vetted partner installers who serve Decatur, AL, and they contact you to schedule an estimate. It's free and there's no obligation.
Other areas we serve in Alabama
Athens · Madison · Moulton · Huntsville · Cullman · All Alabama service areas · All service areas