Short answer: Plan on it. Inside City of Charleston limits, the only work the City exempts from a permit is painting, papering, tiling, carpeting, plug-in portable appliances, and cabinets and countertops with no plumbing, gas or electrical work. HVAC is not on that list. The City's mechanical trade permit covers "Repair of Existing HVAC System" and "New/Upgraded System for Existing Building", and the contractor has to give a City of Charleston business licence number and a South Carolina LLR licence number on it. If your West Ashley address is in unincorporated Charleston County instead, the County issues the permit.
What the City of Charleston actually requires
The City publishes a short list of work that is exempt from a building permit, and it only applies when the property is not in a BAR district or in flood zones AE and VE: "Painting, papering, tiling, carpeting, and plug-in portable appliances," plus kitchen and bathroom cabinets and countertops when no plumbing, fuel gas or electrical work is included. Replacing heating or air conditioning equipment is not on it.
HVAC work goes on the City's mechanical trade permit application, which has boxes for "Repair of Existing HVAC System", "New/Upgraded System for Existing Building" and "New mini-split". It can be a stand-alone permit, or a sub-permit under a master building permit when the HVAC is part of a larger remodel. On the application, the contractor gives a City of Charleston business licence number and a South Carolina LLR licence number and type. The City puts it plainly: contractors "are required to have both a City Business License … AND a SC Contractor License."
What you can do without hiring anyone
First, confirm who your permit office is; a West Ashley mailing address does not tell you. The City says to search your address on its interactive GIS map, and to use Charleston County's GIS if it does not come up in the City's map. Second, check your flood zone: the mechanical application asks for it, and it changes the rules. Third, when quotes come in, ask each HVAC company for its City of Charleston business licence number and its SC LLR licence number, and whether the price includes the permit. The City will verify a business licence on 843.724.3711.
A homeowner can pull residential single-family permits under the City's Non-licensed Owner Intent to Build form, "except fuel-gas". The disclosure says you must supervise the work yourself, the house must be for your own use, and you may not hire an unlicensed person.
How the permit and inspections work
Standalone trade permits are on the City's list of "Express" permits, which can sometimes be approved over the counter if you bring a complete submittal to the Permit Center between 9 a.m. and 4:30 p.m., though the City says "approval is never a guarantee." After payment the permit status changes to "Issued" at midnight, and from then the permit placard can be printed for the job site "and work can commence." The City's Building Inspections Division handles mechanical inspections; the current application lists rough-in (walls only), rough-in (above ceiling), a mechanical test and balance report, and final.
When it becomes serious: flood zones, gas and unpermitted work
- Flood zones AE and VE. In these zones the City requires building permits "for all work on buildings," including replacing and repairing ductwork and mechanical, electrical, plumbing and gas systems, and says "Permits are not exempt following a natural disaster." A storm-damaged unit still needs a permit before the work starts.
- Gas. Fuel gas has its own trade permit and the homeowner route excludes it; a gas-fired system needs a licensed gas contractor for that part.
- Skipping the permit. The City says it is the property owner's responsibility to make sure permits are obtained, and "The homeowner is liable for any fines from unpermitted work."
What is left after the trade fix
For a straight changeout you do not need a general contractor: Charleston County says general contractors cannot do electrical, plumbing or mechanical work themselves, and the licensed HVAC contractor pulls the mechanical permit. General-contractor work comes in when the unit is part of something bigger: an air handler closet reframed to fit new equipment, a ceiling opened and patched after a duct reroute, or a screen around the condenser like the one pictured. If the old system left a ceiling stain, start with water around the air handler. That building work is ours in West Ashley.
Local notes: unincorporated Charleston County
If your address is outside City limits, Charleston County Building Inspection Services issues the permit. Its FAQ says only the homeowner, their immediate family or licensed contractors may work on the property; a homeowner can get permits if they or immediate family do the work and will live in the home for at least two years afterwards; and a specialty contractor needs no permit for work under $1,000 only if "the work doesn't require an inspection and the whole project only involves one trade." Inspections are requested through the County's CSS portal or at [email protected], not by phone.
City of Charleston Permit Center: 843-577-5550. Charleston County Building Inspection Services: (843) 202-6930.
Sources
- City of Charleston — Benefits of Building Permits (exemptions, flood-zone permits, licensing, unpermitted work): charleston-sc.gov/DocumentCenter/View/4036…
- City of Charleston — Mechanical Trade Permit Application: charleston-sc.gov/DocumentCenter/View/4100…
- City of Charleston — Applications & Guidelines (trade sub-permits, owner intent to build): charleston-sc.gov/2483/Applications-Guidel…
- City of Charleston — Non-licensed Owner Intent to Build form and disclosure: charleston-sc.gov/DocumentCenter/View/4012…
- City of Charleston — Permit Center (city limits check, express permits, issuance, inspections): charleston-sc.gov/856/Permit-Center
- Charleston County — Building Inspection Services (FAQ, inspection requests): charlestoncounty.gov/departments/building-…
General guidance for homeowners in Charleston and York County, South Carolina, written from what we see on jobs. Conditions vary house to house; anything structural, gas or electrical is licensed work in South Carolina and should be looked at in person.
Frequently Asked Questions
Do I need a permit to replace my AC in West Ashley?
Inside City of Charleston limits, plan on it. HVAC is not on the City's permit-exempt list, and the City's mechanical trade permit covers repair and upgrade of existing HVAC systems.
Who can pull an HVAC permit in the City of Charleston?
A contractor with both a City of Charleston business licence and a South Carolina LLR licence. A homeowner may qualify for single-family permits, except fuel gas, by filing the City's Non-licensed Owner Intent to Build form.
How do I know if my West Ashley address is in the City or the County?
The City says to search the address on its interactive GIS map. If it does not come up, use Charleston County's GIS.
Does a flood zone change the permit rules in Charleston?
Yes. In flood zones AE and VE, the City requires building permits for all work on buildings, including ductwork and mechanical systems, and permits are not waived after a natural disaster.
Can a general contractor replace my HVAC in Charleston County?
No. Charleston County says general contractors cannot perform electrical, plumbing or mechanical work; each trade has its own licence.