AC Replacement in Charleston, SC

AC replacement in Charleston is a decision before it is a job. When a system is old, leaking or eating parts, the real question is whether one more repair buys useful time. Aero Air Techs tests the system, shows you what failed and puts repair and replacement side by side, so you choose with the numbers in front of you.

Cooling a house for most of the year here is hard on equipment. If you have a working system and no urgent problem, you may not need this page yet. Adding cooling where there is none? See AC installation instead.

Should you repair or replace your air conditioner?

Answer this from the failure, not the birthday on the data plate. Age raises the question, but the condition of the coil and compressor settles it.

What is going on	Usually leans toward
Failed capacitor, contactor or fan motor on a sound unit	Repair
Clogged drain or a small refrigerant leak at a reachable joint	Repair
Compressor failure on an aging system	Replace, once you check manufacturer warranty coverage
Leaking coil on older equipment	Compare both, in writing
Salt has eaten the coil or cabinet	Replace, or see coastal corrosion repair first
Several repairs in recent seasons and a clammy house	Replace, and recheck the sizing
System still runs on R-22	Replace at the next major failure, since supply is limited to recovered stock

As a rough trade rule, the question gets serious somewhere past 10 to 15 years, and earlier near salt water. Plenty of older units still deserve a repair. If yours does, AC repair is the right call and we will say so. Our post on when an old AC is not worth fixing walks through more examples.

AC replacement in Charleston means matching the whole system

A split system is a matched set. The condenser outside, the coil inside and the air handler that moves the air are rated together, and swapping one piece rarely gets you the rated result.

Coil and air handler

Plan on replacing the indoor coil, and often the air handler, with the outdoor unit. New outdoor units generally use a lower-GWP refrigerant, and an R-410A coil generally cannot be paired with one unless the manufacturer lists that exact combination. An AHRI certificate names the tested model numbers, so you can see the pairing for yourself.

Refrigerant

EPA's Technology Transitions rule moved new residential systems toward refrigerants such as R-454B and R-32 from January 1, 2025. Your existing R-410A system can keep running and be serviced, so the rule alone is no reason to replace. Some older-stock R-410A equipment may still be offered, so check what a quote names and how the indoor coil is rated.

High efficiency options

DOE's minimum in the Southeast is 14.3 SEER2 for split ACs under 45,000 BTU/h and 13.8 SEER2 at or above that size. Above the minimum, two upgrades matter most here. Variable-speed compressors and blowers run longer at low speed, which pulls more moisture from the air. A heat pump replaces an AC and furnace with one system, which suits many Lowcountry homes.

Sizing

Do not copy the old tonnage. Insulation, windows and duct leaks may have changed since the first install, and the original unit may have been oversized. A fresh Manual J load calculation takes the guesswork out.

What moves AC replacement cost?

Every house is different, so these factors matter more than any single figure:

• System scope. Outdoor unit, coil and air handler together cost more than a partial swap, when a partial swap is even allowed.
• Efficiency. Higher SEER2 and variable-speed equipment cost more up front.
• Ductwork. Leaky or undersized ducts may need repair or replacement.
• Access. Tight attics, rooftops and raised platforms add labor.
• Electrical. A new disconnect or breaker may be needed.
• Flood and corrosion needs. Added elevation or coated coils change the job.

Rebates now that 25C has ended

The federal credit is gone for new work. Section 25C does not apply to property placed in service after December 31, 2025, so a system installed now earns no credit under it. Other money may still be available, and each program sets its own rules.

• Dominion Energy South Carolina. Rebates of $400 to $500 toward ENERGY STAR central ACs and heat pumps were reported in 2026 by EnergyWise Shop and aggregators, and ductwork improvements up to $300 in existing homes. The same reports put the rebate for an electric furnace to heat pump swap at $650.
• Santee Cooper. Its home rebate program has reported $300 to $400 per heat pump system for its own customers.
• HEAR and HOMES. The SC Energy Office describes these as still being set up, with a statewide launch targeted for 2026 and income limits. Check the state rebate page.

Confirm every figure on Dominion's rebate page or with your utility first. ENERGY STAR units sit above the federal minimum, so a base model may not qualify. Reports say equipment must be installed before you apply, DIY jobs are excluded, a licensed contractor must do the work and applications are due within 90 days with an invoice. See our guide to South Carolina HVAC rebates for more.

How to compare quotes side by side

Totals only mean something when the jobs match. Ask every bidder for these items in writing:

1. Model numbers for the outdoor unit, coil and air handler, plus the AHRI certificate.
2. The SEER2 rating and the refrigerant.
3. A load calculation, or the reason one was skipped.
4. What happens to the ducts, drain, pad and electrical.
5. How old refrigerant is recovered and how the old equipment leaves.
6. How the permit and inspection are handled.
7. Manufacturer warranty terms and any registration steps.

Ask any contractor for a license number and check it on the SC LLR lookup before you sign. A low bid that leaves out the coil is not the same job.

Swap day, start to finish

A typical changeout follows the same order.

1. Protect and prepare. We cover the work path and shut the system down.
2. Recover the refrigerant. EPA Section 608 bars venting it, and technicians who handle it must be certified under that federal rule.
3. Remove the old equipment. Lines, coil and condenser come out.
4. Set the new system. Coil, air handler, condenser and drain go in, and the unit is anchored.
5. Braze, test and evacuate. The line set gets pressure tested and pulled into a deep vacuum.
6. Charge and measure. We check charge, airflow and temperature drop against the manufacturer's numbers.
7. Walk you through it. You see the thermostat and filter and get the paperwork.

Most straightforward swaps take about a day. Duct work or a new platform can extend that.

Flood rules can apply to replacements too. Charleston County says replacement HVAC in A, AE, AH, AO and A99 zones must sit at or above the existing finished floor or the design flood elevation, whichever is lower, and two feet above base flood elevation on a Substantial Improvement. City of Charleston guidance sets its own elevation rule and separates new equipment from like-for-like swaps, and towns write their own rules.

Permits vary too. The City of Charleston's mechanical permit application, Form 5.1, lists a Change Out Condenser and/or Air Handler inspection, but sources conflict on same-size swap exemptions. Ask the Permit Center or your local office, and make sure your quote says how the permit is handled.

Keeping the new unit healthy

Good habits protect the investment. Keep filters fresh, keep shrubs back, rinse the coil if you live near salt water and book a yearly tune-up. Register the equipment with the manufacturer if the terms call for it, and keep the invoice with the model numbers.

Why call Aero Air Techs when the old unit is done?

You should get a straight read on your options, even if the answer is repair.

• Rated 4.9 on Google from 16 reviews, as of October 2026.
• Clear, upfront quote. One customer's note reads "price were as quoted."
• Careful work. Another reviewer wrote that the visit "Paid attention to detail."
• Reachable. Our Google listing shows open 24 hours, 7 days a week.

Replacing systems around Charleston

From our Charleston base we serve North Charleston, Ladson, Moncks Corner, Hollywood and the surrounding areas. Call with your address and the age of your system, and we will talk through the next step.

What decides a replacement quote changes by town.

• North Charleston: Noisette and Filbin creek flood zones can set the height of the new unit.

• Ladson: three counties meet here, so the permit office depends on your street.

• Moncks Corner: the utility may be Santee Cooper, Dominion or Berkeley Electric, and each has its own rebate rules.

• Hollywood: low ground on the Rantowles side makes the pad height worth checking.

• Goose Creek: the city's permit list is explicit, so the quote should name that line.

• Hanahan: older brick ranches may need ductwork looked at along with the condenser.

• Folly Beach: permit values from the past ten years count toward substantial improvement, so old work can change the rules.

• Isle of Palms: salt and storm tide push coating and platform questions onto the quote.

• Summerville: colder nights than the coast make a heat pump swap worth pricing.

• Charleston County: the county's height rule applies to replacements in A, AE, AH, AO and A99 zones.