- 100 questions, 4-hour limit, open-book, computer-delivered through PSI, 70% needed to pass.
- Exam fee is $150; Master license after passing costs $94.50.
- Refrigeration and Air Conditioning is the largest of the six domains - prioritize it.
- Failed first attempt means a 30-day wait; later retests require 60 days.
Exam Snapshot: The Numbers You Must Know
Before you touch a single practice question, memorize the mechanics of the Maryland Master HVACR Contractor License Exam itself. The Maryland Board of Heating, Ventilation, Air Conditioning and Refrigeration Contractors owns the exam, but delivery is handled through PSI test centers. It's a computer-delivered, open-book, multiple-choice exam: 100 questions, a 4-hour time limit, and a 70% passing score. The exam fee is $150, paid as part of your PSI registration process.
Those four numbers - 100 questions, 4 hours, 70%, $150 - are the backbone of every planning decision you'll make, from how many days to study to how you pace yourself in the testing room. For a deeper breakdown of the cost structure, see the MD-MHVACR Certification Cost 2026 breakdown, and for a full discussion of what "hard" actually means for this specific exam, read How Hard Is the MD-MHVACR Exam?.
Eligibility Recap Before You Register
The MD-MHVACR exam isn't open to just anyone with HVAC experience. Maryland requires that applicants have been licensed and regularly employed as a Journeyman, Limited Contractor, Master Restricted Contractor, or HVACR instructor for at least three years. You also must have worked under the direction and control of a licensed Master Contractor, and you need to document at least 1,875 hours of HVACR services in the year immediately preceding your application.
These aren't formalities - the Board checks documentation, and gaps in your employment or hours can delay your eligibility to sit for the exam. If you're still confirming whether you qualify, the full breakdown lives in MD-MHVACR Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Key Takeaway
Gather your three years of documented employment history and your most recent 1,875-hour log before you schedule your PSI appointment, not after.
What You Can (and Can't) Bring Into the Room
Because this is an open-book exam, reference management is a skill in itself. Approved references include the 2012 or 2018 International Mechanical Code, Modern Refrigeration and Air Conditioning (editions 19 through 21), Manual J 2006 eighth edition, OSHA 29 CFR Part 1926, and an ACCA Ductulator.
You're allowed to permanently tab, highlight, and underline these references - but you cannot bring handwritten notes, loose papers, or any outside study guide into the testing room. PSI proctors check books at check-in, so a reference with slip-in sticky notes or margin scribbles can get flagged.
Reference Prep Checklist
Build your open-book kit weeks in advance, not the night before.
- Tab the IMC by chapter, focusing on mechanical ventilation and equipment sections
- Highlight Manual J load calculation tables you reference most often
- Mark the Ductulator's static-pressure and friction-rate scales for quick reads
- Flag OSHA 1926 sections on ladders, confined spaces, and electrical safety
The Six Domains at a Glance
The exam draws its 100 questions from six content areas. Knowing the relative weight of each helps you allocate study hours instead of spreading yourself evenly across topics that don't deserve equal time. A full domain-by-domain walkthrough is available in the MD-MHVACR Exam Domains 2026 Complete Guide, but here's the condensed version for quick review.
| Domain | Focus Area | Reference to Lean On |
|---|---|---|
| Domain 1 | Electrical Knowledge, Motors, and Controls | Modern Refrigeration and Air Conditioning |
| Domain 2 | Piping | IMC, Modern Refrigeration and Air Conditioning |
| Domain 3 | Refrigeration and Air Conditioning | Modern Refrigeration and Air Conditioning, Manual J |
| Domain 4 | Heating Systems | IMC, Modern Refrigeration and Air Conditioning |
| Domain 5 | Air Distribution Systems | Manual J, ACCA Ductulator |
| Domain 6 | Safety | OSHA 29 CFR Part 1926 |
Refrigeration and Air Conditioning is the largest domain on the exam, so it deserves the biggest share of your review time. Don't let the other five domains slide, but don't treat them as equals to Domain 3 either.
Domain 3: Refrigeration and Air Conditioning
As the largest domain, this section covers refrigerant cycles, compressor operation, condenser and evaporator performance, and system troubleshooting drawn largely from Modern Refrigeration and Air Conditioning.
- Superheat and subcooling calculations
- Refrigerant charging and recovery procedures
- Diagnosing common AC system faults
Domain 6: Safety
Safety questions pull directly from OSHA 29 CFR Part 1926, so this is one of the few domains where the source material is a single, tabbable document.
- Fall protection and ladder safety rules
- Confined space entry procedures
- Electrical lockout/tagout requirements
For candidates who want a granular study sequence built around these weightings, the MD-MHVACR Study Guide 2026: How to Pass on Your First Attempt walks through a domain-by-domain plan in more depth than a cheat sheet can.
Retest Waits, Fees, and Insurance Minimums
If you don't pass on the first try, Maryland enforces a mandatory 30-day wait before you can request a retest. If you fail again after that, subsequent retest requests require a 60-day wait. Plan your study calendar around these windows rather than assuming you can walk back into a testing center the next week.
Once you pass, the current Master license fee is $94.50. But passing and paying isn't the finish line for everyone - Master Contractors subject to the insurance requirement must maintain $300,000 in general-liability insurance and $100,000 in property-damage insurance before the license becomes fully active for contracting work.
Reciprocity and Post-Pass Licensing
Maryland maintains HVACR reciprocity with Delaware and Virginia. If you already hold an equivalent license in one of those states, or if you plan to work across state lines after earning your Maryland Master credential, this reciprocity arrangement can simplify the paperwork on the other side of the border.
Employers across residential, commercial, and light-industrial HVACR contracting look for candidates who hold this specific license because it signals you can legally pull permits and supervise work as a Master Contractor in Maryland. If you're weighing whether the credential is worth pursuing given your career goals, Is the MD-MHVACR Certification Worth It? Complete ROI Analysis 2026 covers that decision in more detail, and MD-MHVACR Jobs outlines where license holders typically find work.
Final-Week Review Timeline
A cheat sheet works best as a last-mile review tool, not a replacement for months of preparation. In your final stretch before test day, sequence your review around the domain weighting instead of reviewing chapters in the order they appear in your textbooks.
Refrigeration and Air Conditioning Deep Dive
- Rework superheat/subcooling problems until they're automatic
- Review Modern Refrigeration and Air Conditioning chapters on system diagnostics
Electrical, Piping, and Heating Systems
- Drill motor and controls wiring diagrams
- Cross-check piping code requirements against the IMC
Air Distribution and Safety
- Run duct-sizing practice with the ACCA Ductulator until it's second nature
- Read OSHA 1926 sections on fall protection and confined spaces
Full-Length Timed Practice
- Simulate the 4-hour, 100-question format with tabbed references at hand
- Review missed questions by domain to spot remaining weak spots
This kind of spaced review - tackling your weakest domain first while it's fresh, then rotating through the rest - works far better for a domain-weighted exam like this one than reviewing material in random order. For more on structuring the weeks leading up to your test date, including how it interacts with scheduling deadlines, check MD-MHVACR Exam Dates 2026: Testing Windows, Deadlines & Scheduling.
If you want to gauge your readiness quantitatively rather than just qualitatively, run full-length timed simulations on our practice test platform and track your score against the 70% passing threshold before you ever sit at a PSI center. Repeating timed sets on the main practice site is one of the fastest ways to convert open-book familiarity into actual speed under the clock.
FAQs
The exam has 100 multiple-choice questions with a 4-hour time limit, delivered by computer through PSI in an open-book format.
You need a 70% passing score. For a detailed explanation of how that threshold is applied, see MD-MHVACR Passing Score 2026: Exactly What You Need to Pass.
No. You may bring approved references that are permanently tabbed, highlighted, and underlined, but handwritten notes, loose papers, and outside study guides are prohibited.
Your first retest request requires a 30-day wait after a failed attempt. If you fail again, later retest requests require a 60-day wait.
Maryland has HVACR reciprocity with Delaware and Virginia, which can streamline licensing if you plan to work in those states as well.