CFC Test Study Guide 2026: 40+ Terms & Exam Traps (EPA 608)

TL;DR

The “CFC test” is the informal name for the EPA Section 608 certification exam, which every HVAC technician must pass to legally handle refrigerants. This glossary covers the 40+ most tested terms across the Core, Type I, Type II, and Type III sections, organized by topic so you can study smarter. It includes refrigerant classifications, regulatory terms, equipment definitions, key dates, and the most common exam traps that trip up even experienced techs.

The term “CFC test” has been floating around the HVAC trade for decades. It originally made sense because the EPA Section 608 exam was created specifically to regulate who could handle chlorofluorocarbons. But the exam has evolved far beyond CFCs. Today it covers HCFCs, HFCs, HFOs, A2L refrigerants, and the AIM Act. The old name stuck anyway.

This CFC test study guide is built as a glossary because most existing study resources bury critical definitions inside long paragraphs or scatter them across PDF manuals. Practitioners on Reddit consistently report that memorizing the key terms and repeated practice testing is the most efficient path to passing. A scannable, topic-grouped glossary serves that exact need.

If you’re brand new to HVAC and need foundational context before jumping into exam terms, start with this beginner’s guide to HVAC/R fundamentals. Otherwise, read on.

How the EPA 608 Exam Works (What You Need to Know First)

Before studying individual terms, understand the exam structure. The EPA 608 consists of four sections: Core, Type I, Type II, and Type III. You must pass Core plus at least one other section to receive certification. Pass all four and you earn Universal Certification.

Each section has 25 questions drawn randomly from a pool of roughly 350 possible questions. The passing score is 70% (18 out of 25 correct) on each section. The exam is closed book. You’re allowed a blank piece of scratch paper, a pressure-temperature chart, and a four-function calculator. Nothing else.

One important detail that surprises many people: EPA 608 certification is permanent under federal law. Your card is valid for life once issued. No renewal required.

Practitioners on Reddit’s r/HVAC forum overwhelmingly advise going straight for Universal certification because it future-proofs your career. If you ever move into commercial or low-pressure work, you’ll already be covered.

Study time runs roughly six to eight hours for most people, according to multiple practitioner reports across forums and YouTube channels. As one HVAC blogger put it plainly: “The main way to pass the EPA 608 Exam is to memorize all the possible questions.”

For a deeper look at exam essentials, check out this EPA 608 certification essentials overview.

Refrigerant Types: The Most Confused Category on the Exam

This is where most study time should go. The exam tests your ability to distinguish between refrigerant families, and the differences between CFC, HCFC, and HFC trip up more people than any other topic. One practitioner on an HVAC forum noted that mistaking R-22 for a CFC (it’s actually an HCFC) is one of the most common wrong answers on the test.

CFC (Chlorofluorocarbon)

A compound consisting of chlorine, fluorine, and carbon. CFCs are extremely stable in the lower atmosphere, which is exactly the problem. They drift up to the stratosphere where ultraviolet light breaks them apart, releasing chlorine atoms that destroy ozone molecules.

Examples: R-11, R-12, R-113, R-114, R-115, R-500, R-502

Exam context: Tested heavily in the Core section. CFCs are classified as Class I controlled substances. No one can produce or import them in the U.S. Since 1995, the only source of CFC refrigerants for servicing existing equipment is recovery and recycling.

ODP values: CFC-11 = 1.0 (the baseline), CFC-12 = 1.0, CFC-113 = 0.8, CFC-114 = 1.0, CFC-115 = 0.6.

Exam trap: The exam may ask what elements a CFC contains. The answer is chlorine, fluorine, and carbon. If hydrogen is listed as an option, that makes it an HCFC or HFC, not a CFC.

HCFC (Hydrochlorofluorocarbon)

A transitional refrigerant developed to replace CFCs. HCFCs still contain chlorine, so they still deplete the ozone layer, but their ODPs range from 0.01 to 0.1, far less than CFCs. They are classified as Class II controlled substances.

Examples: R-22, R-123, R-124, R-141b, R-142b

Exam context: Core and Type II/III sections. R-22 is the most commonly referenced HCFC on the exam. R-22 production in the United States ended in 2020.

Exam trap: R-22 is not a CFC. This is tested repeatedly and missed frequently. If a question asks about Class II substances, think HCFCs.

HFC (Hydrofluorocarbon)

HFCs replaced CFCs and HCFCs as the next generation of refrigerants. Because they contain no chlorine or bromine, all HFCs have an ozone depletion potential of zero. However, HFCs are potent greenhouse gases with global warming potentials hundreds to thousands of times higher than carbon dioxide.

Examples: R-134a, R-410A, R-404A, R-507, R-407C

Exam context: Core section for regulation questions, Type II for system-specific questions. HFCs were added to the venting prohibition on November 15, 1995. The AIM Act now mandates an 85% reduction in HFC production and consumption by 2036.

Exam trap: HFCs have zero ODP, but that does not mean they’re unregulated. They are covered under both the venting prohibition and the AIM Act phasedown.

HFO (Hydrofluoroolefin)

The newest generation of refrigerants, designed to have very low global warming potential. HFOs are a type of unsaturated hydrocarbon (the “olefin” part), which makes them break down much faster in the atmosphere than HFCs.

Examples: R-1234yf (automotive AC), R-1234ze (chillers)

Exam context: Increasingly showing up in updated question banks. The exam now includes questions about next-generation replacements.

Key fact: HFOs have much lower GWP than HFCs, but most are mildly flammable, which is why many carry an A2L safety classification.

A2L Refrigerant

An ASHRAE Standard 34 safety classification for “mildly flammable” refrigerants. These refrigerants burn slowly and with relatively low heat compared to highly flammable substances. R-454B, R-32, and R-466A are common A2L refrigerants.

Exam context: Practice question banks now include 19 questions specifically covering A2L refrigerants, including R-454B’s role as a replacement for R-410A. This is where most legacy CFC test study guides fall short, and it’s where updated test questions are being added.

Why it matters: R-454B and R-455A are replacing R-410A under the AIM Act. The R-410A ban in new residential equipment took effect January 1, 2025. Expect A2L questions on any exam taken from 2024 onward.

For a full walkthrough of how refrigerants work within AC and refrigeration systems, see this AC and refrigeration certification guide.

Quick-Reference Table: CFC vs. HCFC vs. HFC vs. HFO

This single table covers a disproportionate number of exam questions. Print it, screenshot it, memorize it.

Refrigerant Mixture Terms

Azeotropic Mixture

A refrigerant blend that behaves like a single-component refrigerant. When it evaporates or condenses, both components change phase at the same temperature. This means it can be topped off without changing composition.

Examples: R-500 (CFC blend), R-502 (CFC blend), R-507A (HFC blend)

Exam context: Core section. Know that azeotropic blends act as a single substance.

Zeotropic Mixture

A blend whose components evaporate and condense at different temperatures. This creates a “temperature glide” during phase changes. More importantly, if a zeotropic blend leaks, the components escape at different rates, a process called fractionation.

Examples: R-407C, R-410A (near-azeotropic, but technically zeotropic)

Exam context: Core and Type II. Fractionation is the reason you must remove the entire charge and weigh in a new charge if a zeotropic system leaks significantly, rather than simply topping off.

Fractionation

The uneven leaking of refrigerant blend components due to different boiling points. After significant fractionation, the remaining refrigerant no longer matches its original composition and may not perform correctly.

Exam trap: The exam tests whether you know that zeotropic blends (not azeotropic) are subject to fractionation.

“Freon”

A trade name originally used by DuPont (now Chemours) for their line of refrigerants. It is not a refrigerant type. The exam will never use the word “Freon” as a correct answer. Think of it like “Band-Aid” versus “adhesive bandage.”

Environmental Science Terms

Ozone Depletion Potential (ODP)

A scale measuring how destructive a substance is to stratospheric ozone, compared to CFC-11. CFC-11 has an ODP of 1.0 by definition. HCFCs range from 0.01 to 0.1. HFCs and HFOs have an ODP of zero.

Exam context: Core section. Expect questions asking you to rank refrigerant families by ODP or identify which type has zero ODP (HFCs).

Global Warming Potential (GWP)

A measure of how much heat a greenhouse gas traps in the atmosphere compared to CO2 over a specific time period (usually 100 years). CO2 has a GWP of 1. R-410A has a GWP of approximately 2,088. HFOs like R-1234yf have GWPs under 5.

Exam context: Core section and AIM Act questions. The AIM Act phasedown is driven entirely by GWP, not ODP. This distinction matters.

Stratosphere vs. Troposphere

The troposphere is the lowest layer of Earth’s atmosphere, where weather happens. The stratosphere sits above it, roughly 6 to 31 miles up, and contains the ozone layer. Ozone in the stratosphere is protective (“good ozone”) because it absorbs harmful UV-B radiation. CFCs are stable in the troposphere but break apart in the stratosphere, which is why they’re so damaging.

Exam context: Core section. The exam tests whether you understand where ozone depletion occurs (stratosphere, not troposphere).

Chlorine Monoxide

An intermediate compound formed when UV light breaks chlorine atoms from CFCs in the stratosphere. Chlorine monoxide reacts with ozone and destroys it. A single chlorine atom can destroy thousands of ozone molecules before it’s deactivated.

UV-B Radiation

The type of ultraviolet radiation that increases at Earth’s surface when the ozone layer thins. Health effects include skin cancer, cataracts, and immune system suppression. This is the “why it matters” behind the entire EPA 608 program.

Regulatory and Legal Terms

Clean Air Act, Section 608

The federal law that makes the exam necessary. Section 608 prohibits intentional venting of ozone-depleting substances and HFC substitutes, with civil penalties exceeding $44,539 per day per violation. It also requires technicians to be certified before purchasing or handling regulated refrigerants.

Exam context: Tested across all sections. Know the venting prohibition, the penalty amount, and that certification is required by law.

Montreal Protocol

An international treaty signed on September 16, 1987, and effective January 1, 1989. Its purpose is to phase out the production of ozone-depleting substances globally. It has been ratified by 198 parties, making it the first universally ratified treaty in United Nations history.

Exam context: Core section. Know the year (1987) and its purpose (phasing out ODS production worldwide).

Kigali Amendment

A 2016 amendment to the Montreal Protocol that extends its scope to include HFCs. While HFCs don’t deplete ozone, their high GWP made them a target for international action. The Kigali Amendment commits participating countries to phasing down HFC consumption.

Exam context: May appear on updated exams in connection with the AIM Act.

AIM Act (American Innovation and Manufacturing Act, 2020)

The U.S. law that mandates an 85% phasedown of HFC production and consumption by 2036. This is the domestic implementation of HFC reduction. It’s the reason R-410A is being replaced by A2L alternatives like R-454B in new equipment.

Exam context: Increasingly tested. Know the target (85% by 2036) and that it applies to HFCs, not CFCs or HCFCs (which are already covered under earlier regulations).

Class I vs. Class II Substances

Class I substances are CFCs and halons, with higher ODPs and earlier phaseout deadlines. Class II substances are HCFCs, with lower ODPs and later phaseout schedules.

Exam trap: The exam may ask which class R-22 belongs to. The answer is Class II. If you mentally associate “R-22 = old refrigerant = must be Class I,” you’ll get it wrong.

Venting Prohibition

It is illegal to intentionally release (vent) CFC, HCFC, or HFC refrigerants into the atmosphere. The CFC/HCFC venting prohibition took effect July 1, 1992. HFCs were added on November 15, 1995.

Exam context: Core section. The two dates are among the most frequently tested facts on the entire exam. Memorize both.

De Minimis Release

A small, unavoidable release of refrigerant that occurs during normal service procedures (connecting or disconnecting hoses, for example). The EPA permits de minimis releases but requires technicians to minimize them. Low-loss fittings are required for this reason.

SNAP Program (Significant New Alternatives Policy)

An EPA program that evaluates and approves substitute chemicals for ozone-depleting substances. SNAP reviews alternatives for safety, environmental impact, and performance.

Civil Penalty

The current penalty for violating Section 608 regulations exceeds $44,539 per day per violation. This applies to technicians, employers, and equipment owners.

Exam trap: The exam asks for the specific dollar amount. “Over $44,000” won’t cut it. Memorize $44,539.

Procedures and Equipment Terms

Recovery

Removing refrigerant from a system and storing it in an external container (recovery cylinder) without testing or processing it.

Plain English: You’re just pulling it out and putting it in a tank.

Recycling

Cleaning recovered refrigerant using oil separation and filter-driers, performed on-site. Recycled refrigerant does not meet ARI-700 purity standards.

Plain English: Basic cleaning on the job site. Good enough to reuse in the same system or same owner’s equipment, but not clean enough to sell.

Reclamation

Reprocessing recovered refrigerant at a certified facility to meet AHRI-700 purity standards. Reclamation is the only process that qualifies refrigerant for resale to a new owner.

Exam context: The recovery, recycling, reclamation distinction appears on virtually every version of the Core exam. Practitioners on HVAC forums report this trio as the single most tested concept.

Memory aid: Recovery = remove. Recycling = rough clean. Reclamation = restore to like-new.

ARI-700 / AHRI-700 Standard

The purity specification that reclaimed refrigerant must meet before it can be resold. Published by the Air Conditioning, Heating, and Refrigeration Institute (AHRI). If the question asks what standard reclaimed refrigerant must meet, the answer is AHRI-700 (formerly ARI-700).

Evacuation

Removing air and moisture from a refrigeration system using a vacuum pump before charging with refrigerant. Proper evacuation prevents ice formation, acid buildup, and system damage.

Exam context: Type II and Type III sections. Know target vacuum levels for different system sizes.

Pressure-Temperature (P/T) Chart

A reference chart showing the relationship between a refrigerant’s pressure and its boiling point. This is one of the few resources allowed during the exam. Learn to read it before test day.

Compound Gauge

A gauge that reads both pressure (above atmospheric) and vacuum (below atmospheric). Found on the low side of a manifold gauge set. The scale typically reads from 30 inches of mercury vacuum to 0 to several hundred psi.

Micron Gauge

Measures deep vacuum levels in microns (one micron = one millionth of a meter). Used during evacuation to verify that a system has reached the required vacuum level. More precise than a compound gauge in the vacuum range.

Filter-Drier

A device installed in the refrigerant line to remove moisture and contaminants. Used in both system installation and recycling equipment. On the exam, filter-driers are associated with the recycling process (not recovery, not reclamation).

Low-Loss Fittings

Fittings designed to minimize refrigerant loss when connecting or disconnecting service hoses. Required on all recovery and recycling equipment manufactured after November 15, 1993.

Self-Contained vs. System-Dependent Recovery Equipment

Self-contained recovery equipment has its own compressor and can recover refrigerant regardless of whether the system’s compressor works. System-dependent equipment relies on the system’s own compressor or pressure differential to push refrigerant into the recovery cylinder.

Exam context: Type I section covers system-dependent recovery (common for small appliances). Type II and III focus more on self-contained equipment.

Nitrogen Pressurization

Using dry nitrogen to pressurize a system for leak testing. Never use oxygen or compressed air, as mixing either with refrigerant oil can cause an explosion.

Exam trap: This is a safety question that appears regularly. If you see “oxygen” as an answer option for pressurization, it is always wrong.

Certification Levels and Exam-Specific Terms

Core Section

Mandatory for all certification types. Covers 25 questions on regulations, environmental impact, refrigerant safety, and general refrigerant handling. Practitioners frequently describe Core as the hardest section because it tests federal law, exact dates, and specific penalty amounts rather than hands-on HVAC skills. Technicians with years of field experience still fail Core by underestimating how regulation-heavy it is.

Type I (Small Appliances)

Covers systems containing 5 pounds of refrigerant or less. Think window AC units, household refrigerators, vending machines, and PTAC units.

Type II (High-Pressure Appliances)

Covers high-pressure and very-high-pressure equipment like residential central AC, heat pumps, commercial refrigeration, and supermarket systems. Type II has the highest fail rate according to practitioner reports. Many candidates struggle because their prep materials focused only on R-22 and skipped the A2L refrigerants now tested.

Type III (Low-Pressure Appliances)

Covers low-pressure equipment, primarily centrifugal chillers using refrigerants like R-11, R-123, or R-245fa. These systems operate below atmospheric pressure during normal operation, which creates unique service challenges (air leaks in rather than refrigerant leaking out).

Universal Certification

Earned by passing all four sections (Core + Type I + Type II + Type III). This is what most people should aim for.

Section 609

A separate EPA certification for servicing motor vehicle air conditioning (MVAC) systems. Section 609 is not part of the 608 exam. If you need details on that certification, here’s a guide to EPA 609 certification for motor vehicle AC.

Key Dates to Memorize

This table alone is worth studying the night before your exam. Every date listed here has appeared on actual test questions.

Study tip: The two dates people forget most are November 15, 1993 (recovery equipment deadline) and November 15, 1995 (HFC venting ban). They both fall on November 15, which helps.

Common Exam Traps (What Catches People Off Guard)

These aren’t obscure edge cases. These are the mistakes that show up in every Reddit thread, every YouTube comment section, and every HVAC forum discussion about the EPA 608 exam. For more detail on each, read this breakdown of common EPA 608 exam mistakes and fixes.

1. Confusing recovery, recycling, and reclamation. Three different procedures with three different definitions. The exam treats them as completely distinct. If a question mentions AHRI-700, the answer involves reclamation. If it mentions filter-driers and on-site cleaning, that’s recycling.

2. Forgetting the 1995 HFC venting date. Many people memorize July 1, 1992, for CFCs/HCFCs but blank on November 15, 1995, when HFCs were added. Both dates appear on the exam.

3. Calling R-22 a CFC. R-22 is an HCFC (Class II). It contains hydrogen, which CFCs do not. This is probably the single most common wrong answer on the test.

4. Not knowing the exact civil penalty amount. The exam asks for $44,539 per day per violation. Rounding to “$40,000” or “$50,000” will cost you the point.

5. Ignoring AIM Act and A2L content. Updated question banks now include material on R-454B, R-32, the R-410A restriction, and ASHRAE A2L classifications. Older study materials don’t cover this. If your CFC test study guide was written before 2023, it’s probably missing these questions.

6. Assuming Type I is easy because the appliances are small. Small appliance rules have their own specific recovery requirements and exemptions that differ from Type II and III.

7. Using oxygen for pressurization in a test scenario. Always nitrogen. Never oxygen, never compressed air. Explosion risk. This is tested as a safety question.

8. Not matching study material to your test provider. As practitioners on HVAC forums consistently advise: find out whether your test center uses ESCO or Mainstream Engineering, then study with that provider’s question bank. The questions come from different pools.

How to Use This CFC Test Study Guide Effectively

Based on what practitioners consistently report across Reddit, YouTube, and HVAC forums, here’s the most effective study approach:

Step 1: Read through this glossary once to get familiar with the terminology landscape.

Step 2: Focus your memorization on the refrigerant comparison table, the key dates table, and the recovery/recycling/reclamation definitions. These three areas cover a disproportionate number of exam questions.

Step 3: Take practice tests. Multiple users confirm that watching study videos paired with repeated practice tests is enough for most beginners. SkillCat offers EPA 608 training and proctored exams on your phone for $10/month, with 4 attempts included and instant results. If you’re looking for a mobile-first, self-paced way to prepare and take the test, start your EPA 608 exam prep with SkillCat.

Step 4: Pay special attention to AIM Act and A2L refrigerant questions. This is where most older study materials have gaps, and where exam providers are adding new content.

Step 5: Review the common exam traps section above the night before your test. These are the points people lose not because they didn’t study, but because they studied outdated or incomplete material.

If you’re studying for the CFC test as part of a broader career move into HVAC, consider reading this HVAC vocational training guide to understand what comes after certification.

Frequently Asked Questions

What is the CFC test?

The “CFC test” is the informal name for the EPA Section 608 Technician Certification exam. It’s called that because the exam was originally created to regulate CFC handling, but it now covers all regulated refrigerants including HCFCs, HFCs, and HFOs.

How many questions are on the EPA 608 exam?

Each section (Core, Type I, Type II, Type III) has 25 questions. If you’re going for Universal certification, that’s 100 questions total across four sections. Questions are pulled randomly from a pool of roughly 350 possible questions.

What score do I need to pass?

You need 70% (at least 18 out of 25 correct) on each section. You must pass Core plus at least one type section to receive any certification.

Does EPA 608 certification expire?

No. EPA 608 certification is permanent under federal law. Once you pass, your certification is valid for life with no renewal required.

How long should I study for the CFC test?

Most practitioners report needing six to eight hours of focused study time. The most effective approach, according to Reddit users and HVAC forum members, is watching study videos and then taking practice tests repeatedly until you consistently score above 80%.

Is the EPA 608 exam open book?

No. The exam is closed book. The only allowed resources are a blank piece of scratch paper, a pressure-temperature chart, and a four-function calculator.

What’s the difference between EPA 608 and EPA 609?

Section 608 covers stationary refrigeration and air conditioning equipment. Section 609 covers motor vehicle air conditioning (MVAC) systems. They are separate certifications with separate exams.

Do I need to know about the AIM Act for the exam?

Yes. Updated exam question banks now include questions about the AIM Act, R-454B, A2L refrigerants, and the R-410A restriction. Any CFC test study guide that doesn’t cover these topics is outdated. This is especially important for the Type II section.

For more EPA certification resources and study material, browse the full EPA certification resource library on SkillCat.