HVAC Basics, a free class from Global Sovereign University: a technician reads R-410A gauges at a condensing unit, low side 118 psi, high side 350 psi, superheat and subcooling of 10 degrees inside target.

A Class · Global Sovereign University · Trades

HVAC

From the physics of heat to a live diagnostic call: thermodynamics, the refrigeration cycle, safety and EPA Section 608, load and duct math, controls, ventilation, furnaces, heat pumps, boilers, troubleshooting and building automation. Twelve lessons, one per chapter of the book. Free, no account, nothing to install.

Step one · Read

The chapter, broken into the separate ideas you will be asked to use. Read it, or have it read to you.

Step two · Work

A bench you can change — the day, the coil, the airflow — and it answers the way the chapter does. Then go put your hands on your own system.

Step three · Prove

A new situation every attempt. Miss one and you are told why that choice fails, and sent back to the exact idea it was testing.

Your progress is kept on your own device. Nothing is transmitted and nobody is asked who you are. This class teaches understanding; it is not a license, it is not EPA Section 608 certification, and it does not replace a qualified technician for refrigerant handling, gas, or high-voltage work.

The twelve lessons

One per chapter, in the book's order. All twelve are open.

    The Certificate of Comprehension

    Working the lessons is practice, and practice does not earn a certificate. The certificate comes from a separate exam that is graded on our server, so no answer key ever reaches your browser and no score can be reported by the student.

    A pass prints a serial-numbered certificate with a link anyone can use to verify it. It records comprehension of the book. It is not EPA Section 608 certification, a trade licence, or a qualification issued by any authority.

    Sit the exam The HVAC simulator and field guide

    The HVAC Apprentice's Field Guide — cover

    The book behind the class

    The HVAC Apprentice’s Field Guide was written by our founder, Dr. Gene A Constant, and donated to the Foundation. Published by Global Sovereign University Press. The class is free. The book is how the Foundation pays for it.

    Buy a copy — it funds a free seat

    Global Sovereign University is a 501(c)(3) nonprofit and book sales are its only income. A purchase is not a tax-deductible donation.

    Questions about the class

    Is the HVAC class free?

    Yes. All twelve lessons are free, with no login and no paywall. The class is taught from The HVAC Apprentice's Field Guide by Dr. Gene A Constant; buying the book helps fund free classes like this one, and it is never required.

    Who is this class for?

    Apprentices, people considering the trade, homeowners who want to understand their system, and working technicians who want the fundamentals in one place: heat, the refrigeration cycle, controls, airflow, heating, cooling, hydronics and diagnostics.

    How is each lesson built?

    Each lesson follows one chapter of the book. You read five ideas, work a hands-on bench that simulates the chapter's decisions, then answer questions about real situations. Your progress is saved in this browser only.

    Is there a certificate?

    Yes. A separate, free exam on the whole book is graded on our server. Score 80% or better for a Certificate of Comprehension with a serial number anyone can verify.

    Does this class give me EPA Section 608 certification?

    No. The class explains what Section 608 requires, but the certificate records comprehension of the book only. It is not an EPA 608 certification, a licence or a trade qualification.

    Do I need tools to take the class?

    No. Every lesson works on screen. The book explains the instruments technicians use, such as gauges, thermometers and a manometer, and the lessons show what their readings mean.

    Accreditation notice: Global Sovereign University is not an accredited institution and does not grant degrees, academic credit, licenses, or industry credentials. Learners who pass GSU's online exams earn GSU certificates of comprehension.