- What the Data Actually Shows
- The 70% Passing Requirement Explained
- Domain Weighting and Where Points Concentrate
- Exam Format, Timing, and Delivery
- Retake Rules and Waiting Periods
- Where Candidates Typically Lose Points
- The Separate SRE Exam Factor
- Building a Preparation Timeline Around the Data
- Frequently Asked Questions
- Passing the R-39R/C-39 trade exam requires 70% correct across 80 scored questions in 210 minutes.
- Refrigeration, Air Conditioning, and Warm Air Heating each carry 12 questions - the heaviest domains by far.
- Retakes require a 30-day wait; a fourth or later attempt requires a 90-day wait.
- PSI may insert 5-10 unscored experimental questions, so the actual test can feel longer than 80 items.
What the Data Actually Shows
Arizona's Registrar of Contractors (ROC) and its testing partner, PSI Services LLC, do not publish a public pass-rate percentage for the R-39R/C-39 (CR-39) residential/commercial air conditioning and refrigeration trade examination. So instead of guessing at a number that isn't officially reported, the useful exercise is to look at the structural data that is published - the passing score, the domain weighting, the timing, and the retake policy - and understand how those mechanics shape a candidate's odds. That structural data tells you far more about your actual chances than a headline statistic ever could.
The trade outline that governs this exam was revised June 8, 2023, and the general PSI candidate bulletin carries a February 18, 2026 date. Both documents lay out exactly what's being tested, how it's scored, and how the exam is delivered. If you want the full breakdown of every content area before diving into pass-rate mechanics, the AZ-ACR Exam Domains 2026: Complete Guide to All 12 Content Areas is the companion resource to read alongside this one.
The 70% Passing Requirement Explained
The trade outline specifies 80 questions and a 70% passing requirement, which works out to roughly 56 correct answers needed out of 80. That threshold is fixed - it doesn't shift based on how other candidates perform on a given day, and PSI does not curve results. This is a criterion-referenced exam: you're being measured against a defined competency standard, not against a bell curve of your peers.
One detail that surprises first-time test-takers: PSI may add 5-10 unscored experimental questions within the same 210-minute window. These questions are indistinguishable from scored items during the test, which means you cannot "skip" what feels like an odd or unfamiliar question - you have to treat every item as if it counts, because you don't know which ones are experimental. For a full walkthrough of exactly how the score threshold works in practice, see AZ-ACR Passing Score 2026: Exactly What You Need to Pass.
Key Takeaway
Plan your pacing assuming up to 90 total questions in the 210-minute block, not just 80 - that buffer prevents you from running short on time near the end of the exam.
Domain Weighting and Where Points Concentrate
The official question allocation across the 12 domains is publicly listed in the trade outline, and it is heavily skewed toward three subject areas. Refrigeration, Air Conditioning, and Warm Air Heating are the joint-largest domains, each contributing 12 questions - 36 of the 80 scored questions, or 45% of the entire exam, sit in just those three areas.
| Domain | Questions |
|---|---|
| Refrigeration | 12 |
| Air Conditioning | 12 |
| Warm Air Heating | 12 |
| Controls and Motors | 8 |
| Fuel Piping Systems | 5 |
| Water Piping Systems | 5 |
| Steam, Hot, Chilled, and Condensing Water | 5 |
| Boilers | 4 |
| Ventilation | 4 |
| Evaporative Coolers | 4 |
| Testing, Balancing, and Inspections | 5 |
| Sizing and Estimating | 4 |
Refrigeration, Air Conditioning, Warm Air Heating
These three domains together decide whether you clear the 70% bar. A candidate who is weak across all three cannot make up the deficit through strength in the smaller domains, because no single small domain carries enough weight.
- Refrigeration cycle diagnostics, metering devices, and system charging
- Cooling load fundamentals and equipment sizing logic
- Combustion, venting, and heat exchanger principles for warm air furnaces
The remaining nine domains - Controls and Motors, Boilers, Ventilation, Evaporative Coolers, Fuel Piping Systems, Water Piping Systems, Steam/Hot/Chilled/Condensing Water, Testing/Balancing/Inspections, and Sizing and Estimating - range from 4 to 8 questions each. They still matter, especially since a handful of easy points in a low-weight domain can be the difference between passing and falling just short. For domain-by-domain study strategies, the AZ-ACR Study Guide 2026: How to Pass on Your First Attempt breaks each content area into concrete study tasks.
Exam Format, Timing, and Delivery
This is a computer-based, multiple-choice exam offered through both test-center and remote-proctored delivery. Regardless of which format you choose, you have 210 minutes to work through up to roughly 90 questions (80 scored plus possible experimental items). That's an average of a little over two minutes per question, though realistically you'll move faster through recall-based items and slower through scenario or calculation-based ones.
Approved open-book references include OSHA 29 CFR Part 1926 (or PSI's selections with the latest available amendments), the 2018 International Fuel Gas Code, and the 2018 International Mechanical Code. You're allowed to bring advance highlighting, underlining, annotations, and permanent tabs into these references - but loose additional papers and writing in the references during the test itself are prohibited. A silent, nonprinting, nonprogrammable, nonscientific calculator is permitted under the general bulletin.
Remote-proctored candidates should note two restrictions that test-center candidates don't face: no scratch paper and no breaks during the exam session. If you're choosing between delivery formats, factor in how you personally handle a 210-minute session with zero pause time.
Retake Rules and Waiting Periods
If you don't clear the 70% threshold, Arizona's retake structure is straightforward but strict on timing. A failed attempt requires a 30-day wait before you can sit again. That waiting period extends significantly if you struggle repeatedly: a fourth or subsequent attempt requires a 90-day wait. Each attempt also carries its own $66 trade exam fee, so repeated failures compound both in cost and in delay before a license application can move forward.
This retake structure is one of the strongest arguments for treating your first attempt as the one that counts. A full cost accounting of exam fees, potential retakes, and related licensing expenses is covered in AZ-ACR Certification Cost 2026: Complete Pricing Breakdown.
Key Takeaway
Budget mentally for one solid attempt rather than planning around a retake - the 30-day minimum wait alone can delay a licensing timeline by a month or more.
Where Candidates Typically Lose Points
Without a published breakdown of missed-question data, the most reliable signal comes from the structure of the exam itself: the domains with the most questions are also where uneven preparation does the most damage. Refrigeration, Air Conditioning, and Warm Air Heating combine technical depth with scenario-style questions - meaning the exam isn't just asking you to recall a fact, it's asking you to apply it to an original trade scenario involving a specific system configuration or fault condition.
Two other patterns show up consistently for candidates preparing for this specific exam:
- Mixing up classification-specific scope. Candidates sometimes prepare generically for "HVAC" topics without confirming which tasks fall under the R-39R/C-39 classification versus adjacent trade classifications. Confirming exact classification scope early avoids wasted study time.
- Underweighting the smaller domains entirely. Because Boilers, Ventilation, Evaporative Coolers, and Sizing and Estimating each carry only 4 questions, some candidates skip them to focus purely on the big three domains. That's risky - losing all 4 points in two or three small domains can be exactly the margin that separates a pass from a fail near the 70% line.
For a broader look at how difficult this exam is relative to the material and time constraints, see How Hard Is the AZ-ACR Exam? Complete Difficulty Guide 2026.
The Separate SRE Exam Factor
The R-39R/C-39 trade exam is not the only test standing between a qualifying party and licensure. Arizona also requires a separate online Statutes and Rules Exam (SRE), priced at $61, which is scheduled and scored independently of the $66 trade exam. Candidates sometimes conflate the two exams' content or preparation timelines, which can lead to under-preparing for one while over-preparing for the other.
Because the SRE draws from Arizona Revised Statutes §32-1122 and §32-1123.01 rather than the technical trade outline, it deserves its own dedicated study block rather than being squeezed in at the last minute. Treat it as a distinct milestone in your overall licensing plan, not an afterthought to the trade exam.
Building a Preparation Timeline Around the Data
Given the domain weighting, the most defensible way to allocate study time is proportional to question count, with extra buffer time on the three heaviest domains. A simple structure:
Refrigeration and Air Conditioning
- Refrigeration cycle, charging, and metering devices
- Cooling load basics and equipment matching
Warm Air Heating and Controls and Motors
- Combustion, venting, and furnace troubleshooting
- Motor types, control circuits, and safety devices
Piping systems, Boilers, and Steam/Water domains
- Fuel piping and water piping code requirements
- Boiler operation and steam/chilled water basics
Remaining domains, code-book navigation, and full timed practice
- Ventilation, Evaporative Coolers, Sizing and Estimating, Testing/Balancing/Inspections
- Timed practice under 210-minute constraints with open-book references
This kind of spaced review across weekly blocks works well specifically because it mirrors the exam's own weighting - front-loading the domains worth the most points while still guaranteeing coverage of the smaller ones before test day. For a condensed reference you can review in the final days before your appointment, the AZ-ACR Cheat Sheet 2026: One-Page Review of Must-Know Facts consolidates the highest-yield facts across all 12 domains.
Once you've built familiarity with the material, running full-length timed sessions on our practice test platform is the closest simulation available to the real 210-minute, 80-question format - including the discipline of pacing yourself against a clock rather than studying material in isolation.
Frequently Asked Questions
No official pass-rate percentage is published for this specific trade exam. What is published are the mechanics that determine outcomes: 80 scored questions, a 70% passing requirement, and 210 minutes to complete the test.
With 80 scored questions and a 70% passing requirement, you need roughly 56 correct answers. PSI may add 5-10 unscored experimental questions, but those don't count toward your score.
Refrigeration, Air Conditioning, and Warm Air Heating each carry 12 questions and together make up 45% of the exam - they should receive the largest share of your preparation time.
You must wait 30 days before retaking. If you reach a fourth or later attempt, the waiting period extends to 90 days, and each attempt requires paying the $66 trade exam fee again.
No. The SRE is a separate online exam costing $61, scheduled and scored independently from the $66 R-39R/C-39 trade examination.
Understanding how the data around this exam is structured - the domain weighting, the fixed 70% threshold, and the retake timeline - gives you a far more actionable picture than a single pass-rate number ever could. For a wider view of eligibility before you even schedule, review AZ-ACR Requirements 2026: Eligibility, Prerequisites & How to Qualify, and when you're ready to test your readiness under real exam conditions, start a full practice session to see where you stand against each domain.