A theory-first introduction to heating, ventilation, air conditioning, refrigeration, and the official EPA Section 608 Core and Type I/II/III test-topic families. It does not include equipment practice, an EPA-approved exam, certification, an OSHA Outreach card, or authorization to service refrigerant equipment. Taught by Cyber Ballet. Level: Beginner. Category: Skilled Trades. Enroll to access AI-powered lessons, quizzes, live instructor sessions, and a verifiable certificate.