Why it matters to you
Code compliance is why two replacement quotes for the same Charleston home can differ: items like condensate overflow protection, sealed and insulated ducts in crawlspaces and attics, and proper venting are required, not optional extras. Every inspection item traces back to a fire, a ceiling collapse, or a carbon monoxide case somewhere in the code's history.
Practical guidance
You don't need to read the code — ask your contractor whether the quote includes everything the adopted codes require and who will pull the permit. The SC Building Codes Council publishes the currently adopted editions if you want to check which apply at permit time.