Manual J calculator · SC
Manual J load calculation for South Carolina.
Run an ACCA Manual J 8th Edition residential load calculation with climate context pre-loaded for South Carolina — ASHRAE design temperatures for 4 top metros, IECC 2009 (residential, with SC amendments), and SC LLR licensing context already accounted for in the assumption defaults.
Pre-loaded scenario
Charleston, SC (Charleston County) · ASHRAE zone 3A · winter 99% DB 27°F · summer 0.4% DB 92°F · MCWB 78°F.
ASHRAE 169-2021 · ACCA MJ8 §6
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01 · ASHRAE design conditions
Top 4 metros in South Carolina — design temperatures used in Manual J.
These are the ASHRAE 99% heating and 0.4% cooling design temperatures — the values Manual J uses for the design day, not the absolute extremes. Equipment sized to these conditions undersizes for ~35 hours per year in summer (acceptable per ACCA convention) and ~22 hours per year in winter.
| Metro | County | Zone | Winter 99% DB | Summer 0.4% DB | MCWB |
|---|---|---|---|---|---|
| Charleston | Charleston County | 3A | 27°F | 92°F | 78°F |
| Columbia | Richland County | 3A | 24°F | 96°F | 75°F |
| Greenville | Greenville County | 3A | 21°F | 93°F | 73°F |
| Myrtle Beach | Horry County | 3A | 28°F | 91°F | 77°F |
Source: ASHRAE 169-2021 (republished in EERE Building America Guide 7.3, public domain). DB = dry-bulb. MCWB = mean coincident wet-bulb at the 0.4% cooling design hour.
02 · Energy code
South Carolina energy code: IECC 2009 (residential, with SC amendments)
Adopted 2013. Manual J load-calc documentation requirements flow from the state energy code; verify your specific AHJ’s submittal rules before relying on the baseline.
- South Carolina's residential energy code is based on IECC 2009 with state amendments — among the older active baselines in the country. Local jurisdictions may adopt newer editions but few have done so.
- The SC Building Codes Council has been studying IECC 2021 adoption; verify current adoption status with the SC Department of Labor, Licensing & Regulation before relying on the 2009 baseline.
Source: SC Building Codes Council — Energy · verified 2024-05-30
03 · South Carolina HVAC labor data
BLS wages and employment for HVAC mechanics in South Carolina.
These are state-level wages for occupation code 49-9021 — Heating, Air Conditioning, and Refrigeration Mechanics and Installers — from the most recent BLS Occupational Employment and Wage Statistics release.
- Median hourly wage
- $22.74
- Mean annual wage
- $48,710
- Employment estimate
- 5,180
Source: BLS OEWS May 2023, SOC 49-9021 (state-level) · released 2024-04-03. Loaded labor rates billed to customers typically run 2.5–3.5× the technician wage after overhead.
04 · License & permit
HVAC licensing in South Carolina: SC LLR.
State-level HVAC contractor licensing is administered by the South Carolina Department of Labor, Licensing & Regulation — Contractor's Licensing Board. Licenses renew every 2 years.
License types
- Mechanical Contractor — Air Conditioning (commercial)
- Residential Specialty Contractor — HVAC
Permits
SC requires a mechanical permit for new HVAC installation and most change-outs in jurisdictions with active inspection programs (all major metros). Permit thresholds and CE requirements differ between commercial and residential specialty licenses.
Replacement permit: typically required.
Coastal SC counties (Horry, Charleston) layer hurricane-zone requirements for outdoor equipment anchoring; confirm local product approval before purchasing equipment.
05 · FAQ
Common Manual J questions for South Carolina contractors.
+How important is latent load in coastal South Carolina?
Charleston and Myrtle Beach both sit at 77–78°F summer design wet-bulb — among the highest sustained latent loads in the U.S. Sensible-only Manual J sizing under-equips dehumidification by 15–20% in coastal SC. The Manual J 8th-edition latent calculation (§8) is critical, and BuildSolver runs it automatically.
+Why is SC still on IECC 2009?
The SC Building Codes Council has not formally adopted a newer residential energy code statewide; review for IECC 2021 has been ongoing. Local jurisdictions can adopt more stringent codes; few do. Always verify the current baseline with the AHJ before assuming.
+Does Charleston have hurricane-zone requirements for HVAC?
Coastal SC counties (Horry, Charleston, Beaufort) require equipment anchoring per Florida-style wind-zone provisions — uplift-rated condenser pads, hurricane straps, and clearances above design flood elevation. The Manual J sizing itself is unaffected; the install hardware list grows.
+What's the average HVAC wage in South Carolina?
BLS OEWS May 2023 reports $22.74/hr median for SC HVAC mechanics and installers — about $48,710 annual mean — slightly below the national median.
+Can BuildSolver document a Manual J for an SC permit?
Yes — BuildSolver's audit-trail output (assumption-by-assumption with ACCA citations) is generally accepted by SC AHJs that require documentation. Verify with the specific building department before submitting; SC's older code baseline means documentation requirements vary by jurisdiction.
+Why is Greenville heating-dominant compared to Charleston?
Greenville sits in the Upstate at higher elevation — winter design DB is 21°F vs Charleston's 27°F. Manual J heating loads for the same building in Greenville run 15–20% higher than coastal SC. Equipment selection often shifts toward heat-pump dual-fuel in the Upstate, while coastal SC stays heat-pump-only.
Try a South Carolina load calculation now.
The chat will ask follow-up questions like an experienced engineer — square footage, construction type, window count, insulation level — and run the Manual J on your inputs with South Carolina’s ASHRAE design temperatures applied automatically. About 90 seconds end to end.
Start South Carolina calculationRelated · same climate zone
Other states with similar ASHRAE climate zones.
Manual J assumptions for infiltration, latent share, and design temperatures behave similarly across states that share an ASHRAE zone. The pages below carry the same procedural defaults with their own local design temps and licensing context.
Data last reviewed 2026-05-19 · underlying sources as of 2024-04-03