- What OH-REF Certification Actually Is
- Who Governs and Administers the Exam
- Exam Format and Scoring
- The Five OH-REF Content Domains
- The Business and Law Companion Exam
- Eligibility to Sit for the Exam
- Fees, Insurance, and Licensing Costs
- How to Approach Preparation
- Renewal and the Compliant Contractor Program
- Who Actually Needs This Credential
- Frequently Asked Questions
- OH-REF is the Ohio Refrigeration Contractor trade exam, administered by PSI for OCILB, covering food/product preservation refrigeration, not comfort HVAC.
- The trade exam has 60 scored questions across 5 domains, plus 10 unscored pretest items, with a 70% passing score in 3 hours.
- A separate Business and Law exam (50 scored, 5 pretest, 2 hours, 70% passing) is also required for licensure.
- PSI charges $69 per exam or retake; failed sections require a 60-day wait before retesting, up to five retests per year.
What OH-REF Certification Actually Is
OH-REF refers to the Ohio Refrigeration Contractor License Exam, the trade-specific licensing test that candidates must pass to become a licensed refrigeration contractor in the state of Ohio. This is not a comfort-cooling or general HVAC credential. The scope is specifically refrigeration systems used for food and product preservation - walk-in coolers, commercial freezers, ice machines, refrigerated display cases, and the piping, controls, and refrigerants that keep those systems running safely and efficiently.
Because the acronym "OH-REF" appears elsewhere in unrelated industries, it's worth being precise: everything on this site refers only to the Ohio trade exam administered through the Ohio Construction Industry Licensing Board. If you're researching what this certification means for your career, start with our plain-language breakdown at What Is OH-REF? or the terminology primer at OH-REF Meaning.
Who Governs and Administers the Exam
The Ohio Construction Industry Licensing Board (OCILB), part of the Ohio Department of Commerce's Division of Industrial Compliance, sets the licensing rules and requirements for refrigeration contractors. Actual test delivery is handled by PSI, a third-party testing provider that administers the exam on computer at approved test centers.
PSI publishes an official candidate information bulletin that lists reference materials, scoring rules, and administrative policies. The most recent version referenced by this site was updated February 7, 2024. If you want the full regulatory backstory - statutes, administrative code citations, and how OCILB structures the license - see OH-REF Certification and OH-REF Requirements 2026.
Exam Format and Scoring
The Ohio Refrigeration Contractor trade examination consists of 60 scored questions plus 10 unscored pretest questions, for 70 total items administered in a single sitting. Candidates have a 3-hour time limit and must score 70% or higher to pass. The unscored pretest questions are mixed in without being identified, so every question should be treated as if it counts.
Only PSI's onscreen calculator is permitted during the test - outside calculators, phones, and other devices are not allowed. For a deeper walkthrough of exactly what "passing" requires and how the scoring works, read OH-REF Passing Score 2026.
| Exam Component | Scored Questions | Pretest Questions | Time Limit | Passing Score |
|---|---|---|---|---|
| Refrigeration Trade Exam | 60 | 10 | 3 hours | 70% |
| Business and Law Exam | 50 | 5 | 2 hours | 70% |
The Five OH-REF Content Domains
The 60 scored questions on the trade exam are distributed across five official domains. Understanding this weighting is the single most important step in building a study plan, because it tells you exactly where your preparation hours will have the greatest payoff.
Domain 1: General Knowledge & Requirements - 18 questions
The largest domain on the exam, covering Ohio-specific licensing rules, code references, safety practices, and general trade knowledge that applies across refrigeration work.
- Ohio Mechanical Code provisions relevant to refrigeration
- Safety procedures and jobsite requirements
- General trade terminology and administrative rules
Domain 2: Refrigeration Piping - 12 questions
Covers proper piping practices for refrigerant lines, including sizing, materials, and installation methods specific to commercial refrigeration systems.
- Suction, discharge, and liquid line configurations
- Pipe sizing and material selection
Domain 3: Refrigerants - 6 questions
Focuses on refrigerant types, handling, and properties as they apply to food and product preservation equipment.
- Refrigerant classifications and characteristics
- Safe handling and recovery practices
Domain 4: Refrigeration Systems & Controls - 15 questions
The second-largest domain, testing knowledge of how refrigeration systems and their controls function together, including troubleshooting logic.
- Compressors, condensers, evaporators
- Control systems and component interactions
Domain 5: Testing & Inspection - 9 questions
Covers procedures for testing installed systems and preparing for inspection, ensuring work meets code and safety standards.
- System testing procedures
- Inspection readiness and documentation
For a domain-by-domain study breakdown with more detail on subtopics and question style, see OH-REF Exam Domains 2026: Complete Guide to All 5 Content Areas.
Key Takeaway
General Knowledge & Requirements (18 questions) and Refrigeration Systems & Controls (15 questions) together make up more than half the exam - prioritize these two domains first.
The Business and Law Companion Exam
Passing the trade exam alone does not earn a refrigeration contractor license in Ohio. Candidates must also pass a separate Business and Law examination, which covers contracts, liability, insurance, and general business practices required of licensed contractors. This exam has 50 scored questions plus 5 pretest questions, a 2-hour time limit, and the same 70% passing requirement as the trade exam.
The trade exam and the Business and Law exam are charged and scheduled separately, so budget and study time for both. Many candidates underestimate the Business and Law portion because it feels less technical - but it still requires dedicated review, since it's scored independently and must also be passed at 70%.
Eligibility to Sit for the Exam
Standard eligibility to apply for the OH-REF trade exam requires:
- Being at least 18 years old
- U.S. citizenship or lawful resident status
- Five years of documented trade experience immediately preceding the application
There are two recognized alternative paths:
- Holding an Ohio Professional Engineer (PE) license combined with three years of trade construction-business experience
- Five years of experience as an Ohio governmental trade inspector
All applicants must submit experience documentation and complete a BCI/FBI background check as part of the application process. If you're not sure which path fits your background, our detailed breakdown at OH-REF Requirements 2026: Eligibility, Prerequisites & How to Qualify walks through documentation expectations in more depth.
Fees, Insurance, and Licensing Costs
Understanding the full cost picture before you register helps avoid surprises. Here's how the fees break down:
- $69 per PSI examination or retake - trade exam and Business and Law exam are charged separately
- $25 application fee
- $25 initial license issuance fee
- Active contractors must maintain at least $500,000 in liability insurance
- $60 standard annual renewal fee, requiring 10 continuing-education hours
For a complete line-item cost analysis, including how retake fees and renewal cycles add up over time, read OH-REF Certification Cost 2026: Complete Pricing Breakdown.
How to Approach Preparation
Because the OH-REF trade exam weights domains so unevenly - 18 questions in General Knowledge & Requirements versus only 6 in Refrigerants - an effective study plan allocates time proportionally rather than spreading effort evenly across all five domains.
General Knowledge & Requirements + Refrigeration Systems & Controls
- Review Ohio Mechanical Code sections relevant to refrigeration
- Study compressor, condenser, and control system interactions
Refrigeration Piping + Testing & Inspection
- Practice pipe sizing and material selection scenarios
- Review system testing and inspection documentation procedures
Refrigerants + Business and Law Review
- Cover refrigerant handling and classification (smallest domain, 6 questions)
- Begin Business and Law content since it's a separately scored exam
Full Practice and Reference Organization
- Take full-length timed practice sessions on our practice test platform
- Pre-highlight and index your approved reference books, since handwritten notes aren't allowed on test day
This ordering front-loads the heaviest-weighted domains while leaving Refrigerants - the lightest domain at just 6 questions - for a shorter review window. If you want a more detailed methodology, including how to judge your own readiness before scheduling, see OH-REF Study Guide 2026: How to Pass on Your First Attempt and How Hard Is the OH-REF Exam? Complete Difficulty Guide 2026.
Renewal and the Compliant Contractor Program
Passing OH-REF and getting licensed is not a one-time event. Ohio requires ongoing renewal to keep a refrigeration contractor license active:
- Standard renewal: $60 annually, with 10 continuing-education hours required
- Compliant Contractor Program: after a qualifying year, existing licensees may complete 8 hours annually for renewal, or 24 hours for a $180 three-year renewal
This tiered structure rewards contractors with a track record of compliance by reducing the frequency (or per-year cost) of continuing education. It's a detail many first-time candidates overlook while focused on passing the initial exam, but it's worth understanding early since it affects long-term licensing costs.
Who Actually Needs This Credential
The OH-REF license is required for anyone who wants to legally operate as a refrigeration contractor in Ohio - installing, servicing, or maintaining commercial refrigeration systems used for food and product preservation. This includes contractors working with:
- Restaurants and commercial kitchens needing walk-in cooler and freezer installation or service
- Grocery and convenience stores maintaining refrigerated display cases
- Cold storage and warehouse facilities
- Ice machine manufacturers and service companies
Because this is a distinct trade from comfort-cooling HVAC, contractors who only work on residential or commercial air conditioning systems typically do not need this specific license - but those expanding into commercial refrigeration work do. To understand what career paths and employers typically look for this credential, see OH-REF Jobs and OH-REF Salary Guide 2026: Complete Earnings Analysis.
If you're still weighing whether pursuing this license fits your career goals, our analysis at Is the OH-REF Certification Worth It? Complete ROI Analysis 2026 covers the tradeoffs in more depth, and our practice test platform can help you gauge your current readiness before committing to the application fees.
Frequently Asked Questions
No. OH-REF covers refrigeration systems for food and product preservation - coolers, freezers, ice machines, and refrigerated display cases - not comfort-cooling HVAC systems.
The trade exam has 60 scored questions plus 10 unscored pretest questions, for 70 total, administered within a 3-hour time limit with a 70% passing requirement.
Yes. Ohio also requires a Business and Law examination with 50 scored questions plus 5 pretest questions, a 2-hour limit, and the same 70% passing score.
You must wait 60 days before retesting that portion. PSI allows up to five retests per year, and each attempt costs $69.
Standard eligibility requires five years of documented trade experience immediately before applying, or alternative paths through an Ohio PE license with three years of relevant experience, or five years as an Ohio governmental trade inspector.