For the purposes of this article, the following words and phrases shall have the meanings respectively ascribed to them by this section:
   (a)    "Board" means the Board of Examiners of warm air heating contractors created by this article.
   (b)    "Warm air heating contractor" means any person, persons, firm or corporation who or which installs one or more warm air heating systems, except unvented stoves, for the purpose of furnishing heat within the City, excepting property owners who install, repair, alter, clean, or add to a warm air heating system located in their own residence; provided, that an owner who installs any type of warm air heating system in his own residence, shall take out all permits for such work as are required by the City.
   (c)    "Warm air heating system" means either a gravity or forced air unit which shall consist of casing, heat exchanger, burner, vent pipe, and may have automatic controls, warm air supplies, cold air returns, filters, humidifier, and such other appurtenances. (1978 Code Sec. 5-55)