Oklahoma HVACR Unlimited Contractor Exam Prep - Live Virtual + Self Study Training

Prepare for the Oklahoma HVACR Unlimited Contractor examination with a comprehensive combination of live virtual instruction and structured self-study training. This program is built around the technical subjects, calculations, HVACR concepts, code requirements, safety standards, and contractor business topics associated with Oklahoma HVAC/R Unlimited Contractor licensing.

The Oklahoma HVAC/R Unlimited Contractor license is regulated by the Oklahoma Construction Industries Board and represents the highest HVAC/R mechanical contractor category in the state. The license authorizes qualifying contractors to install, alter, modify, service, maintain, or repair cooling products, systems, and equipment, including process piping; heating equipment and associated process piping; sheet metal; natural gas piping; and refrigeration systems.

Unlike the HVAC/R Limited Contractor classification, the Unlimited license is not restricted to systems of 25 tons or less or heating equipment of 500,000 Btu/h or less per appliance. Candidates preparing for this examination therefore need broad knowledge of commercial and residential HVACR systems, refrigeration, heating, ventilation, duct systems, natural gas, electrical controls, load calculations, piping, equipment installation, troubleshooting, and safety.

Live Virtual + Self Study Training combines organized instructor-led preparation with the flexibility to review technical material independently. Live instruction helps candidates work through major examination topics and understand how the references connect with the tested material. Self-study provides additional opportunities to practice calculations, review code requirements, navigate reference books, and reinforce challenging HVACR concepts.

The examination is open book, making reference navigation an important part of preparation. Candidates should become comfortable using the International Mechanical Code, International Fuel Gas Code, HVACR technical references, load-calculation materials, mathematics reference, Ductulator, and OSHA construction-safety material before examination day.

Additional Oklahoma mechanical and business-law references support preparation for the contractor licensing process. These materials address licensing requirements, bidding and estimating, project management, contracts, finances, labor and personnel, workers’ compensation, insurance, bonds, liens, payroll, and other responsibilities associated with operating a mechanical contracting business.

Exam Details

The Oklahoma HVACR Contractor Unlimited examination is administered by PSI after the Oklahoma Construction Industries Board determines that an applicant meets the qualifications to proceed with testing.

• Exam: Oklahoma HVACR Contractor Unlimited
• Number of Questions: 90
• Passing Score: 70%
• Passing Raw Score: 63 correct answers
• Time Allowed: 240 minutes
• Testing Provider: PSI

The technical examination covers six major subject categories:

• Electrical Knowledge and Controls: 15 questions
• Natural Gas: 12 questions
• Air Distribution Systems: 25 questions
• Refrigeration and Air Conditioning Systems: 20 questions
• Heating Systems: 15 questions
• Safety: 3 questions

Air Distribution Systems is the largest portion of the examination with 25 questions. This area can include duct definitions, sizing and design, assembly and installation, hangers and supports, duct materials and shapes, insulation, fire and smoke control, hoods and exhaust systems, testing and balancing, ventilation requirements, and plans and symbols.

Refrigeration and Air Conditioning Systems account for another 20 questions. Candidates should prepare for refrigeration theory, refrigerants, equipment sizing and design, equipment and components, piping, installation, system operation, troubleshooting, and maintenance.

Heating Systems account for 15 questions and include heating theory, system types, combustion air, vents and chimneys, equipment sizing, equipment installation, operation, troubleshooting, maintenance, and hydronic systems and piping. Electrical Knowledge and Controls also contains 15 questions, including electrical theory, motors, DC circuits, AC circuits, and controls.

With 90 questions and 240 minutes available, candidates have an average of approximately two minutes and forty seconds per question. Efficient use of the permitted references can be particularly important for calculations, equipment-sizing questions, duct problems, electrical questions, and detailed code requirements.

Mechanical contractor candidates also prepare for the Oklahoma Mechanical Business and Law examination. That examination contains 50 questions, requires a 70% passing score with 35 correct answers, and allows 120 minutes.

Open Book Test

The Oklahoma HVACR Contractor Unlimited examination is an open-book test. Candidates are responsible for bringing permitted reference materials to the examination center and complying with PSI's rules concerning those references.

The current examination reference list includes the ACCA Ductulator, International Mechanical Code, 2018 edition with Oklahoma revisions, International Fuel Gas Code, 2018 edition with Oklahoma revisions, Manual N - Load Calculation for Small Commercial Buildings, Fifth Edition, Mathematics for Plumbers and Pipefitters, 8th Edition, and Code of Federal Regulations - 29 CFR Part 1926 (OSHA) with applicable amendments.

Modern Refrigeration and Air Conditioning is also used for examination preparation. PSI's current transition schedule permits the 22nd edition beginning August 13, 2026. The 20th and 21st editions are accepted under the current transition rules, with the 20th edition scheduled to be discontinued as an allowed reference beginning November 1, 2026.

Approved reference materials may be highlighted, underlined, and indexed before the examination. Permanent tabs are permitted for indexing. Temporary tabs such as Post-it notes are not allowed. Candidate-added writing is not permitted in the references before or during the examination session.

For an open-book HVACR examination, simply having the books available is not enough. Candidates should repeatedly practice choosing the appropriate reference, locating the relevant section or table, interpreting the information, and applying it to the question being asked.

Licensing Steps

The Oklahoma Construction Industries Board regulates mechanical contractor licensing and determines eligibility for the HVAC/R Unlimited Contractor category.

1. Gain qualifying mechanical experience. Build and document verifiable experience in the mechanical trade.
2. Meet journeyman-level qualifications. Oklahoma mechanical contractor applicants must first satisfy the applicable requirements associated with journeyman qualification.
3. Complete the additional contractor experience requirement. Mechanical contractor applicants must meet the journeyman requirements plus an additional year of qualifying mechanical trade experience.
4. Maintain the required relationship with the mechanical firm. A mechanical contractor must be a permanent employee, owner, partner, or officer of the mechanical firm.
5. Submit the mechanical contractor application. Provide the Oklahoma Construction Industries Board with the required application and supporting experience documentation.
6. Receive authorization for examination. The Board reviews eligibility before an applicant proceeds to testing.
7. Schedule examinations through PSI. Approved applicants arrange their HVACR Contractor Unlimited and applicable Mechanical Business and Law examinations.
8. Prepare with the exam references. Study HVACR theory, codes, calculations, duct design, refrigeration, heating, natural gas, electrical controls, and safety.
9. Complete the required examinations. Achieve the required passing scores for the contractor licensing process.
10. Address active contractor requirements. Complete applicable insurance, bond, and other requirements before operating under an active Oklahoma mechanical contractor license.

State Requirements

Oklahoma requires mechanical contractor applicants to meet the applicable journeyman qualifications plus an additional year of mechanical trade experience. Oklahoma defines one year of verifiable experience as 2,000 hours.

All mechanical contractors must also be a permanent employee, owner, partner, or officer in the mechanical firm associated with the contractor license.

The HVAC/R Unlimited Contractor license authorizes the contractor to install, alter, modify, service, maintain, or repair cooling products, systems, and equipment, including process piping; heating equipment, including process piping; sheet metal; natural gas piping; and refrigeration.

The Unlimited category is important for contractors performing HVAC work beyond the limitations of the HVAC/R Limited classification. Oklahoma identifies the Limited category as applying to cooling systems of no more than 25 tons and heating equipment with an input of no more than 500,000 Btu/h per appliance. Work beyond those limitations requires the applicable Unlimited HVAC/R license.

After satisfying examination requirements, contractors must also address the requirements necessary to maintain an active Oklahoma mechanical contractor license, including applicable bond and insurance obligations.

Reference Books

• Ductulator
  A practical duct-sizing reference used to support air-distribution calculations and duct-system preparation for the HVACR Contractor Unlimited examination.
• International Mechanical Code, 2018
  This code reference supports preparation for mechanical system installation, ventilation, duct systems, equipment, exhaust, combustion air, and other mechanical-code requirements. The examination uses the 2018 edition with Oklahoma revisions.
• International Fuel Gas Code, 2018
  This reference supports preparation for natural gas piping, sizing, materials, valves, connectors, supports, testing, combustion-related requirements, and fuel-gas installations. The examination uses the 2018 edition with Oklahoma revisions.
• Modern Refrigeration and Air Conditioning, 22nd Edition
  This HVACR technical reference supports preparation in refrigeration theory, air conditioning, refrigerants, equipment, electrical controls, troubleshooting, installation, maintenance, heating, and other trade knowledge. PSI permits the 22nd edition beginning August 13, 2026.
• Manual N - Commercial Load Calculation for Small Commercial Buildings, 5th Edition
  This ACCA reference supports commercial load-calculation and equipment-sizing preparation for small commercial buildings.
• Mathematics for Plumbers and Pipefitters, 8th Edition
  This mathematics reference supports trade calculations involving measurements, piping, formulas, geometry, and other mathematical concepts useful in mechanical exam preparation.
• Code of Federal Regulations - 29 CFR Part 1926 (OSHA)
  This construction-safety reference supports preparation for personal protective equipment, safety training, ventilation, first aid, hazardous materials, fall protection, lockout/tagout, ladders, scaffolds, and related workplace safety requirements.
• Oklahoma Mechanical Licensing Act, Oklahoma Statutes, Title 59, Chapter 43A
  This statutory reference covers Oklahoma mechanical licensing authority, requirements, contractor responsibilities, and regulated mechanical activities.
• Oklahoma Mechanical Industry Regulations, Oklahoma Administrative Code, Title 158, Chapter 50
  This Oklahoma regulatory reference covers mechanical license classifications, contractor qualifications, firms, apprentices, licensing requirements, insurance, bonds, and other industry rules.
• Oklahoma Fine Schedule of the Construction Industries Board, Oklahoma Administrative Code, Title 158, Chapter 10
  This reference supports preparation for Oklahoma Construction Industries Board compliance and enforcement topics.
• Oklahoma Lien Law, Oklahoma Statutes, Title 42, Chapter 3
  This statutory material supports contractor business-law preparation involving construction liens and project-related payment rights and responsibilities.
• NASCLA Contractors Guide to Business, Law and Project Management, Basic 14th Edition
  This contractor business reference supports preparation for bidding, estimating, project management, contracts, financial topics, labor, risk management, insurance, and business operations.
• Oklahoma Workers’ Compensation Act, Oklahoma Statutes, Title 85A, Chapter 1
  This Oklahoma statutory reference supports preparation for workers’ compensation, personnel, employment, and risk-management topics associated with contractor business operations.

Test Information and Study Materials

A productive HVACR Unlimited Contractor study plan should reflect the weighting of the examination. Air Distribution Systems and Refrigeration and Air Conditioning Systems together account for 45 of the 90 questions, making these two categories especially important.

For air distribution, candidates should practice duct sizing and design, duct assembly, installation, supports, insulation, ventilation, hoods and exhaust systems, fire and smoke control, testing, balancing, and plans and symbols. Use the Ductulator and Manual N regularly rather than waiting until the final stages of preparation.

Refrigeration and air-conditioning review should include refrigeration theory, refrigerants, equipment components, system sizing, piping, installation, troubleshooting, maintenance, and system operation. Modern Refrigeration and Air Conditioning can support both technical review and reference-navigation practice.

Heating preparation should include equipment sizing, combustion air, vents and chimneys, heating theory, hydronic systems, piping, installation, troubleshooting, and maintenance. Natural gas study should include piping, valves, connectors, sizing, materials, hangers, supports, and testing.

Electrical Knowledge and Controls deserves dedicated study as well. Review motors, basic electrical theory, AC and DC circuits, controls, and electrical troubleshooting associated with HVACR equipment.

For Mechanical Business and Law, organize preparation around estimating, project management, contracts, financial matters, labor, workers’ compensation, insurance, bonds, payroll, liens, licensing requirements, and Oklahoma mechanical regulations.

Live Class Schedule

The live training schedule is organized around the books and technical references used on the exam. Click Here to View the Current Live Class Schedule.

Live virtual instruction gives Oklahoma HVACR Unlimited Contractor candidates a structured opportunity to work through complex technical subjects with organized guidance. Students can then reinforce those subjects independently through code review, calculation practice, book navigation, and practice-oriented study.

Combining live classes with self-study can help candidates maintain a consistent preparation schedule across refrigeration, heating, air distribution, natural gas, electrical controls, safety, calculations, and contractor business-law topics.

How 1 Exam Prep Helps You Reach Your Goal

1 Exam Prep supports Oklahoma HVACR Unlimited Contractor candidates through organized study guidance, HVACR trade-focused review, practice-oriented preparation, reference navigation, and a structured approach to technical and contractor business-law preparation.

Live virtual instruction helps organize the 90-question technical examination into manageable study categories. Self-study gives candidates the repetition needed to reinforce HVACR theory, practice load and duct calculations, review equipment requirements, and become more comfortable using the permitted references.

Reference navigation is especially important for this open-book examination. Students can practice identifying whether a question requires the International Mechanical Code, International Fuel Gas Code, Manual N, Ductulator, mathematics reference, refrigeration text, or OSHA material and then locate the required information efficiently.

Trade-focused preparation addresses air distribution, refrigeration, air conditioning, heating, natural gas, electrical controls, equipment sizing, system installation, troubleshooting, maintenance, and safety. Contractor business-law review adds preparation for estimating, project management, contracts, finances, employees, insurance, bonds, liens, and licensing responsibilities.

By combining instructor-led training with independent preparation, 1 Exam Prep gives candidates a structured way to build technical knowledge, improve reference-navigation skills, practice calculations, and prepare for the Oklahoma HVACR Unlimited Contractor licensing examinations.

Is the Oklahoma HVACR Unlimited Contractor exam open book?

Yes. The Oklahoma HVACR Contractor Unlimited examination is open book and allows the approved technical references identified for the examination, subject to PSI's reference-material rules.

How many questions are on the Oklahoma HVACR Unlimited Contractor exam?

The examination contains 90 questions. Candidates need a 70% passing score, corresponding to 63 correct answers, and have 240 minutes to complete the examination.

What is the largest subject on the HVACR Unlimited exam?

Air Distribution Systems is the largest individual category with 25 questions, followed by Refrigeration and Air Conditioning Systems with 20 questions.

Does the exam include electrical and natural gas questions?

Yes. Electrical Knowledge and Controls accounts for 15 questions, while Natural Gas accounts for 12 questions on the current examination outline.

What books should I study?

The provided technical references include the Ductulator, 2018 International Mechanical Code, 2018 International Fuel Gas Code, Modern Refrigeration and Air Conditioning, 22nd Edition, Manual N, Mathematics for Plumbers and Pipefitters, 8th Edition, and 29 CFR Part 1926 OSHA construction regulations.

Does an Oklahoma HVACR contractor also prepare for Business and Law?

Yes. Oklahoma mechanical contractor candidates also prepare for the Mechanical Business and Law examination, which contains 50 questions, allows 120 minutes, and requires a 70% passing score.

Does this course include live virtual and self-study training?

Yes. This program combines live virtual instruction with independent self-study preparation covering technical HVACR subjects, code navigation, calculations, safety, and contractor business-law material.

Where can I view the current live class schedule?

Visit the Live Class Schedule to view current class dates. The live training schedule is organized around the books and technical references used on the exam.