(1) Certificate of competency requirements of this chapter shall not apply to:
(a)  Any person who installs or maintains a heating, ventilation and air conditioning system in a single or duplex family dwelling, including accessory buildings, quarters and grounds in connection with such dwelling; provided that such person owns or is a contract purchaser of the premises; and provided further that such person shall comply with the standards and rules applicable to heating, ventilation and air conditioning installation or repairs as provided in this chapter.
(b)  Farm buildings located outside the incorporated limits of any city; and a farm building is hereby defined to be a structure located on agricultural zoned property and designated and constructed to house farm implements, hay, grain, poultry, livestock or other horticultural products and includes sheds, barns, corrals or fences. This definition does not include a place for human habitation or a place of regular employment where agricultural products are extracted, processed, treated or packaged; a place used by the public; or conditioned livestock housing.
(c)  Logging, mining or construction camps when heating, ventilation or air conditioning installations are made to conform to the recommendations of the department of health and welfare.
(d)  Work on heating, ventilation or air conditioning systems on premises owned or operated by an employer who regularly employs maintenance or construction heating, ventilation and air conditioning journeymen, provided that alterations, extensions and new construction shall comply with the minimum standards and rules applicable to heating, ventilation and air conditioning practices in accordance with the provisions of this chapter.
(e)  Modular buildings, as defined in section 39-4301, Idaho Code, that are constructed in the state of Idaho for installation on building sites outside the state; provided however, that no modular building shall be installed on a building site in the state of Idaho until it has been approved and bears the insignia of approval of the division as being in compliance with the requirements set forth in section 39-4304, Idaho Code.
(f)  A nonprofit organization that is chartered to build houses and that has tax-exempt status under section 501(c)(3) of the Internal Revenue Code, including a religious corporation, and such organization’s volunteers, performing HVAC installations for a single-family dwelling unit. An organization described in this paragraph shall designate a primary contact person with whom inspectors may communicate.
(2)  Apprentice registration requirements shall not apply to high school students enrolled in an educational program recognized by the board in which the performance of HVAC installation is a formal component of the program. The exemption is limited to students performing residential installations as part of such program under the constant on-the-job supervision of a licensed journeyman, and a permit for the work is obtained from the authority having jurisdiction. Work hours performed by such students shall not apply toward apprentice work requirements.