Spray foam insulation in Fort Mill, SC: get up to 3 quotes from vetted local installers
Request free quotes from up to three vetted spray foam installers serving Fort Mill and nearby York County. Below: what your climate zone means for open vs closed cell, how much insulation to ask for, South Carolina's energy code, and the rebates we could verify.
- Climate zone: 3A (2021 IECC)
- Attic target: R-49 (ENERGY STAR, uninsulated attic)
- State code: 2009 IECC
- Utility rebates we verified: Duke Energy Carolinas Smart $aver
- 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 Fort Mill and ZIP codes whose center is within about 20 miles of it go to our Fort Mill, SC partner installers (34 ZIP codes): 28012, 28032, 28056, 28101, 28104, 28105, 28108, 28134, 28173, 28202, 28203, 28204, 28205, 28206, 28207, 28208, 28209, 28210, 28211, 28212, 28214, 28217, 28226, 28244, 28270, 28273, 28274, 28277, 28278, 28280, 28282, 29707, 29708, 29715. 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
Fort Mill's central point is in York 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 Fort Mill service radius: Gaston County (3A), Lancaster County (3A), Mecklenburg County (3A), Union 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 Fort Mill, SC
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.
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.
South Carolina energy code
2009 IECC, effective January 1, 2013. Future updates require new legislation.
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 Fort Mill, SC
Census figures for Fort Mill town (ACS 2020–2024 5-year estimates): about 11,463 housing units, a median year built of 2011, 13% built before 1980 and 54% built in 2010 or later. 78% are single-family detached homes and 0% are mobile/manufactured homes. 83% of occupied homes are owner-occupied, with a median owner-reported home value of $487,500.
- About 54% of homes were built in 2010 or later, so a lot of local demand is new construction and newer homes. If you're building, ask the installer to show how the foam R-value meets the energy code your city enforces.
- 64% of homes heat with utility gas. Spray foam makes a house much tighter, which changes how gas furnaces, water heaters and fireplaces draft, so ask whether the installer (or your HVAC contractor) will do combustion safety testing after the job. Some utility rebates require it.
Rebates and incentives for Fort Mill, SC
Utility programs that may apply, depending on which utility serves your address:
Duke Energy Carolinas Smart $aver
Duke's Smart $aver program lists insulation and air-sealing rebates through participating contractors. We could not confirm the current Carolinas amounts on Duke's own pages, so ask the installer to show you the current offer.
Read on the program's own page October 16, 2026. Programs change; confirm before you sign.
South Carolina state Home Energy Rebates
Not yet launched South Carolina Home Energy Rebates
Electrification/appliance rebates (HEAR): "Rebates are not currently available but are expected to launch in 2026."
Whole-home efficiency rebates (HOMES/HER): "The programs are expected to launch statewide in 2026."
Max rebate (per official page): Qualifying households could receive up to $14,000 in rebates for eligible appliances and upgrades.
Official source: South Carolina Energy Office. Status text compiled via referencesource.org, last checked by them August 25, 2026. Full South Carolina rebate page →
What spray foam costs (national published ranges)
We don't have enough local quotes for Fort Mill, SC 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 Duke Energy Carolinas Smart $aver, and who files the paperwork.
- Whether they'll do (or coordinate) combustion safety testing if you have gas appliances.
FAQ
What climate zone is Fort Mill, SC in?
York 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 Fort Mill, SC?
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 Fort Mill, SC 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). South Carolina's code: 2009 IECC.
Are there spray foam or insulation rebates in Fort Mill, SC 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: Duke Energy Carolinas Smart $aver. South Carolina's state Home Energy Rebate program status: Not yet launched.
How much does spray foam cost in Fort Mill, SC?
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 Fort Mill, SC, and they contact you to schedule an estimate. It's free and there's no obligation.
Other areas we serve in South Carolina
Rock Hill · Spartanburg · Greenville · Anderson · All South Carolina service areas · All service areas