(a)   No person shall engage in the business of heating, ventilation and air conditioning (HVAC) contracting in the City until he or she has first obtained a license to do so.
   (b)   No person shall perform any HVAC work within the City other than a person holding an HVAC license from the City, an employee of a person holding such a license from the City and on the direct payroll of such licensee, or a person working on a regular full-time basis for a manufacturing institution while working on or about such factory, except that any person may perform HVAC work in a house owned and occupied by him or her as his or her residence if he or she complies with the requirements of the Ohio Mechanical Code or the International One and Two Family Dwelling Code pertaining to HVAC permits.