As per the FL DBPR:
(6) “Contracting” means, except as exempted in this part, engaging in business as a contractor and includes, but is not limited to, performance of any of the acts as set forth in subsection (3) which define types of contractors. The attempted sale of contracting services and the negotiation or bid for a contract on these services also constitutes contracting. If the services offered require licensure or agent qualification, the offering, negotiation for a bid, or attempted sale of these services requires the corresponding licensure. However, the term “contracting” shall not extend to an individual, partnership, corporation, trust, or other legal entity that offers to sell or sells completed residences on property on which the individual or business entity has any legal or equitable interest, or to the individual or business entity that offers to sell or sells manufactured or factory-built buildings that will be completed on site on property on which either party to a contract has any legal or equitable interest, if the services of a qualified contractor certified or registered pursuant to the requirements of this chapter have been or will be retained for the purpose of constructing or completing such residences.
“Class A air-conditioning contractor” means a contractor whose services are unlimited in the execution of contracts requiring the experience, knowledge, and skill to install, maintain, repair, fabricate, alter, extend, or design, if not prohibited by law, central air-conditioning, refrigeration, heating, and ventilating systems, including duct work in connection with a complete system if such duct work is performed by the contractor as necessary to complete an air-distribution system, boiler and unfired pressure vessel systems, and all appurtenances, apparatus, or equipment used in connection therewith, and any duct cleaning and equipment sanitizing that requires at least a partial disassembling of the system; to install, maintain, repair, fabricate, alter, extend, or design, if not prohibited by law, piping, insulation of pipes, vessels and ducts, pressure and process piping, and pneumatic control piping; to replace, disconnect, or reconnect power wiring on the load side of the dedicated existing electrical disconnect switch; to install, disconnect, and reconnect low voltage heating, ventilating, and air-conditioning control wiring; and to install a condensate drain from an air-conditioning unit to an existing safe waste or other approved disposal other than a direct connection to a sanitary system. The scope of work for such contractor also includes any excavation work incidental thereto, but does not include any work such as liquefied petroleum or natural gas fuel lines within buildings, except for disconnecting or reconnecting changeouts of liquefied petroleum or natural gas appliances within buildings; potable water lines or connections thereto; sanitary sewer lines; swimming pool piping and filters; or electrical power wiring. A Class A air-conditioning contractor may test and evaluate central air-conditioning, refrigeration, heating, and ventilating systems, including duct work; however, a mandatory licensing requirement is not established for the performance of these specific services.