Furnace Replacement Cost in Charleston, South Carolina
Our 2026 estimate for furnace replacement in Charleston, SC is $3,400 to $8,200. That puts Charleston 6% above the national average, mainly because of higher incomes and home values, which push labor rates up.
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Charleston Weather and HVAC Load
In a normal year, Charleston racks up 1,623 heating and 2,447 cooling degree days (NOAA 1991-2020 normals). Cooling carries most of the load. Heating equipment gets light use, so a furnace here often outlasts the AC it's paired with. On average, Charleston gets 6 freezing nights and 24 days above 90°F per year. For a 2,000 sq ft house, this climate points to a heating load somewhere near 35,000 BTU/h. Treat that as a starting number. A Manual J calculation will move it up or down based on insulation and windows.
| Heating degree days / year | 1,623 |
|---|---|
| Cooling degree days / year | 2,447 |
| Nights at or below 32°F | 6 |
| Days above 90°F | 24 |
| Average low / high | 61.1°F / 73.3°F |
Charleston Housing Stock
Half the homes in Charleston were built before 1994 (Census ACS median), so the typical house is about 32 years old. Plenty of houses from this period still run original 1990s or early-2000s equipment, which is past its expected service life. Charleston has roughly 37,000 owner-occupied homes, or 55.6% of households. Homes here have a median value of $469,100 and households a median income of $90,038. Those two numbers drive the labor adjustment in our estimate.
Charleston County had 11 hail days and 34 days with damaging thunderstorm winds from 2020 through 2025, according to NOAA storm records. The largest hail reported was 1.25 inches across. Hail flattens the thin aluminum fins on condenser coils and cuts airflow. After a big storm, take a look at the outdoor unit; homeowners insurance often covers the damage. Charleston County also had 8 tornado days in that period.
When Replacement Makes Sense
- A repair quote runs past a third of the cost of a new unit
- Gas or electric bills keep climbing even though usage hasn't changed
- Some rooms stay cold, the burner short-cycles, or the ignitor keeps failing
- A tech found a cracked heat exchanger, or the CO detector has gone off
What Moves the Price
- Single-stage, two-stage or modulating gas valve
- BTU size, which should come from a Manual J load calculation
- New PVC venting if you move to a condensing model
- Permit and inspection fees, which the local building department sets
- Condition of the existing ductwork and any changes it needs
- AFUE rating: a basic 80% unit vs. a 96% condensing furnace
We raised the national figures about 6% for Charleston using local income, home values and the equipment size this climate needs. Real bids can still come in outside the range, so collect three written quotes.
What the Quote Should Cover
- The new furnace, filter rack and thermostat wiring
- Combustion and safety tests
- Gas line and vent connections
- Removing and hauling away the old furnace
- The permit and the manufacturer warranty registration
South Carolina Permits, Efficiency Rules and Rebates
South Carolina is in the DOE's Southeast region, where new split central air conditioners need at least 14.3 SEER2 (13.8 SEER2 for systems of 45,000 BTU/h and up). Expect the contractor to pull a mechanical permit for a replacement job in Charleston. If a bidder suggests skipping it, move on. Also ask for a South Carolina license or registration number and proof of insurance. The federal 25C tax credit ended for equipment installed after December 31, 2025, so incentives now come mostly from utilities and state programs. Check your electric and gas utility's rebate page before you pick equipment.
Before You Hire
- Look up utility rebates on 95%+ AFUE units before you buy.
- Make sure all three quotes are for the same AFUE and staging, or you can't compare them.
- Replace it in early fall if you can. A no-heat emergency in January costs more and leaves you fewer choices.
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Furnace Replacement Questions from Charleston Homeowners
How much is furnace replacement in Charleston?
Plan on $3,400 to $8,200, with most jobs near $6,000. Equipment efficiency, house size and the condition of the ducts and wiring decide where your quote falls.
When is the best time to schedule furnace replacement in Charleston?
Between late fall and early spring. With 24 days over 90°F, Charleston contractors are booked solid all summer, and off-season jobs are easier to schedule and negotiate.
How long does a furnace replacement take?
A straight swap is usually done in one day, somewhere between 4 and 10 hours. Moving to a condensing furnace with new PVC venting can add a few more.
Is a high-efficiency furnace worth it?
In cold climates, a 95%+ AFUE furnace usually earns back the price difference in lower gas bills. Where winters are mild, the payback can take a very long time.
Furnace Replacement Near Charleston
- Mount Pleasant $4,100 to $9,900
- North Charleston $2,800 to $6,900
- Columbia $2,800 to $6,900
- Rock Hill $3,000 to $7,400
Sources: U.S. Census Bureau ACS 5-year estimates 2019-2023 and 2024 population estimates; NOAA NCEI U.S. Climate Normals 1991-2020, station Charleston City; NOAA Storm Events Database 2020-2025, Charleston County. Prices are our estimates, not contractor quotes. Updated 2026.