Idaho Code § 54-5008: Certificate a prerequisite.

On and after July 1, 2004, it shall be unlawful for any person or firm, copartnership, association or corporation to engage in the business, trade, practice or work of heating, ventilation and air conditioning in this state unless such person or responsible person representing such firm, copartnership, association or corporation, has successfully passed an examination as provided herein and has been issued a state certificate of competency. Such certificate of competency shall not be transferable.