Insulation requirements in South Carolina
Short answer
South Carolina spans climate zone 3. For most of the state (zone 3), the DOE recommends about R49–R60 of attic insulation, with more in its colder areas.
Climate zones
3
Most of the state
Zone 3
Recommended R-values for South Carolina
Based on zone 3, which covers most of South Carolina. Colder parts of the state (higher zones) need more — enter your ZIP for your exact numbers.
| Area | Recommended R-value | Blown fiberglass |
|---|---|---|
| Attic / ceiling | R49–R60 | 24.0" |
| Exterior walls | R20–R21 | 8.4" |
| Floors | R19–R25 | 10.0" |
| Crawlspace / basement wall | R5 | 2.0" |
South Carolinarebates & tax credits
The federal 25C tax credit (30% of insulation materials, up to $1,200/yr) applies everywhere. South Carolina's IRA rebate programs are administered by the state and rolling out on their own timeline. Check the official finder for South Carolina's current status and how to apply.
Find South Carolina's rebate programs →Last verified 2026-07-07.
Your exact numbers
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Frequently asked questions
How much insulation do I need in South Carolina?
South Carolina is in IECC climate zone 3. For most of the state the DOE recommends about R49–R60 in the attic, with more in colder areas. Enter your ZIP for the exact zone.
Are there insulation rebates or tax credits in South Carolina?
Yes — the federal 25C tax credit covers 30% of insulation materials (up to $1,200/year), and South Carolina's IRA HOMES/HEAR rebate programs (up to $1,600 for insulation) are administered by the state. Check the official finder for current South Carolina status.
What climate zone is South Carolina in?
South Carolina is entirely in IECC climate zone 3.