As used in this act:

(a) “Mechanical heating, ventilation and air conditioning contractor” means any person, firm, copartnership, corporation, association or combination thereof, who undertakes or offers to undertake for another, for hire, the planning, laying out, supervising and installing or making of additions, alterations and repairs in the installation of mechanical heating, ventilation and air conditioning systems;

(b) “master heating, ventilation and air conditioning mechanic” means any person having the necessary qualifications, training, experience and technical knowledge to properly plan, lay out and supervise the installation and repair of mechanical heating, ventilation and air conditioning systems;

(c) “journeyman heating, ventilation and air conditioning mechanic” means any person having the necessary qualifications, training, experience and technical knowledge to install and repair mechanical heating, ventilation and air conditioning systems;

(d) “general contractor” means any person having the necessary technical knowledge to properly plan and supervise the unlimited erection, alteration, addition or repair of any building or structure;

(e) “building contractor” means any person having the necessary technical knowledge to properly plan and supervise the erection, remodel or addition to any building not exceeding three stories in height and nonstructural remodeling of any building; and

(f) “residential contractor” means any person having the necessary technical knowledge to properly plan and supervise the erection, remodeling, addition, repair or improvement of one or two family dwellings.