Mississippi Residential HVAC

Mississippi Residential HVAC Exam: Complete 2026 Study Guide

If you're working toward your Mississippi HVAC contractor license, the Mississippi residential HVAC exam is the checkpoint standing between you and the ability to take on jobs worth $10,000 or more. Pass it, and you're authorized to work statewide under a state license. Skip it, and you're limited to smaller jobs — or relying entirely on local permit rules. This guide covers everything: exam format, topic weights, sample questions, required references, and proven study strategies.

Want a quick feel for what you're up against? Start with our free practice exam — no account needed.

Exam Overview: Format, Time, and Passing Score

The Mississippi residential HVAC exam is administered by PSI and delivered on a computer at approved test centers. Here's what to expect:

• Questions: 80 scored questions
• Time limit: 240 minutes (4 hours)
• Passing score: 70% — you need at least 56 correct answers
• Format: Multiple-choice, open-book
• Delivery: Computer-based at PSI test centers

The open-book format is a significant advantage — but don't let it create a false sense of security. Four hours sounds like plenty of time, but you'll spend real minutes flipping through references if you haven't pre-tabbed and highlighted them. Knowing your books cold is what separates passing on the first attempt from running out of time.

Your score appears on screen immediately after you finish. Pass, and you get a performance summary. Fail, and you get a diagnostic report showing exactly where you struggled — useful information for your next attempt.

Who Needs This License?

• Projects $10,000 or more: A residential HVAC license from the Mississippi State Board of Contractors (MSBOC) is required.
• Projects under $10,000: No state license required, but check with your local city or county permit office.
• Commercial work or projects over $50,000: A commercial Certificate of Responsibility with a mechanical classification is required — a different credential entirely.

Visit the state licensing website for current application requirements.

Exam Topics and What They're Worth

The exam draws from 19 topic areas. The heaviest-weighted topics deserve the most study time — here's how the 80 scored questions break down:

Ducts alone accounts for 14 questions — nearly 18% of your score. Nail duct construction, sealing, pressure classification, and support requirements and you've got a real head start.

Sample Questions

These are representative of what you'll see on the Mississippi HVAC PSI exam. Try answering them before checking — then take our free practice exam to see how you really stack up.

Question 1 — Insulation (Hard)
When performing a Manual J residential load calculation, upgrading duct wall insulation from R-6 to R-8 in unconditioned spaces typically produces what approximate reduction in the sensible duct load?
- A) 15 to 20 percent
- B) 3 to 6 percent
- C) Less than 1 percent
- D) 10 to 15 percent

What it tests: Whether you understand how R-value increments translate to actual load reductions — a calculation-based judgment question.

Question 2 — Fuel Oil (Medium)
On a two-pipe buried tank installation, what is the recommended termination point for the suction line inside the tank?
- A) Approximately 12 inches from the bottom
- B) At the very bottom of the tank
- C) At the midpoint of the tank
- D) Approximately 6 inches from the bottom

What it tests: Fuel oil system installation details — a code and component knowledge question.

Question 3 — Insulation (Medium)
For duct board, duct liner, and factory-made rigid ducts not normally subjected to compression, which thickness value is used to determine the insulation R-value?
- A) Installed compressed thickness
- B) Nominal insulation thickness
- C) 75 percent of nominal thickness
- D) Aged thickness after 90 days

What it tests: Precise knowledge of insulation measurement standards — easy to miss if you're guessing.

Question 4 — Furnaces and Heaters (Medium)
You are replacing a 5 kW electric heating element in a residential electric furnace. What is the approximate heat output in Btu/hr that this single element produces?
- A) 10,000 Btu/hr
- B) 34,000 Btu/hr
- C) 51,000 Btu/hr
- D) 17,000 Btu/hr

What it tests: Unit conversion between kilowatts and Btu/hr — a math question that rewards knowing your conversion factors cold.

Question 5 — Ducts (Medium)
When a designer does not designate a pressure class on the contract drawings, what is the default basis of compliance for all duct upstream of variable air volume (VAV) boxes?
- A) ½ in. wg (125 Pa)
- B) 1 in. wg (250 Pa)
- C) 2 in. wg (500 Pa)
- D) 3 in. wg (750 Pa)

What it tests: Default pressure classification rules from the IMC — a code-lookup question that rewards tabbed references.

Don't guess and move on. Use these to identify gaps now, before exam day.

What Types of Questions to Expect (By Topic)

Here's a topic-by-topic breakdown of the kinds of problems you'll face — and how many practice questions we offer for each area:

• Insulation (16 practice questions): R-value requirements for unconditioned spaces, vapor retarder rules for cooling ducts, flame spread and smoke index limits under IMC Section 604
• Hangars and Supports (15 practice questions): Hanger spacing by duct shape, trapeze load calculations, upper attachment methods, riser support intervals
• Sound, Vibration & Seismic Control (6 practice questions): Vibration isolation requirements, seismic anchorage per IMC 301.18, oil canning and cross-breaking techniques
• Heating and Cooling Principles (36 practice questions): Conduction, convection, and radiation; sensible vs. latent heat; refrigeration cycle stages; Manual J fundamentals
• Refrigerants (37 practice questions): CFC/HCFC/HFC/HFO classifications, ODP and GWP, EPA Section 608 requirements, ASHRAE 34 safety classifications, cylinder color codes
• Load Calculations (61 practice questions): HTD/CTD design conditions, R-value, U-value, K-value, HTM calculations for fenestration and opaque surfaces, heating and cooling loads
• Testing, Adjusting and Balancing (7 practice questions): Anemometers, pitot tubes, flow hoods; duct leakage testing; blower door ACH50 results; psychrometric chart use
• Controls (50 practice questions): Thermostat types and sensing elements, heat and cooling anticipators, programmable thermostat setup, oil burner primary controls and cad cell operation
• A/C and Heat Pump Equipment (32 practice questions): Compressor types, metering devices (TXV, EEV, capillary tube, fixed orifice), reversing valve operation, filter-driers, accumulators
• Furnaces and Heaters (23 practice questions): Ignition system types, oil burner components, electric resistance heating calculations, combustion efficiency testing, furnace configurations
• Chimneys, Flues and Vents (15 practice questions): Appliance venting categories I–IV, vent sizing tables, connector slope and length limits, chimney termination height requirements
• Combustion Air (16 practice questions): Indoor volume method, two-permanent-openings method, duct materials and sizing, primary vs. excess air
• Ducts (93 practice questions): Rectangular duct gauge and reinforcement, spiral and longitudinal seam requirements, leakage classes, sealant application, supply/return layouts, hanger spacing
• Ventilation and Exhausts (15 practice questions): Dryer exhaust duct length limits, Type I and Type II kitchen hoods, minimum ventilation rates by occupancy, natural ventilation calculations
• Safety (10 practice questions): PPE selection, fall protection systems, ladder safety, hazardous substance exposure limits
• Fuel Gas (50 practice questions): CSST bonding, pipe sizing by longest-length and branch-length methods, allowable pressure drop, gas piping materials
• LP Gas (40 practice questions): LP piping materials and sizing tables, single- and two-stage regulators, burial depth, pressure testing, leak detection
• Fuel Oil (14 practice questions): Fuel grades and properties, tank installation, two-pipe system suction line placement, nozzle selection and spray patterns
• Piping (25 practice questions): Steel, copper, CSST, and polyethylene standards; shutoff valves and regulators; pressure testing and purging procedures

Total: 561 practice questions across all topics.

Required Study Materials

The Mississippi residential HVAC exam is open book — but only these approved references are allowed. Get them, tab them, and highlight them before exam day.

• OSHA 29 CFR 1926 — Safety standards for construction; covers PPE, fall protection, and hazardous materials
• International Mechanical Code 2021 — The primary code reference for duct construction, venting, combustion air, and equipment requirements
• Manual J - Residential Load Calculation — Essential for load calculation questions; know how to navigate it quickly
• Modern Refrigeration and Air Conditioning — Covers refrigerants, equipment types, refrigeration cycle, and controls in depth
• 2018 International Fuel Gas Code (IFGC) — Required for fuel gas, LP gas, combustion air, and piping questions
• Residential Oil Burners — Covers oil-fired equipment, fuel grades, storage tanks, and nozzle selection

Tab every major topic area. Highlight formulas, tables, and code section numbers. Permanent tabs only — Post-It notes are not allowed in the exam room.

Study Tips That Actually Work

Prioritize by exam weight. Ducts (14 questions), plus Heating/Cooling Principles, Load Calculations, A/C and Heat Pumps, Furnaces, Fuel Gas, and Piping (5–6 questions each) make up the bulk of your score. Master these first.

Work through answer choices systematically. Read every option in order. If one looks right, treat it as your current best. Each remaining choice must beat that selection to replace it. Don't stop at the first answer that seems correct — check all four, then confirm your final pick actually answers the question as written.

Don't skip unfamiliar words. On hard questions, you may not recognize several answer choices. That doesn't mean they're wrong or made up — exam writers only use real terminology. If you can firmly evaluate just one choice, start there. Eliminate what you can; every elimination improves your odds.

Manage your nerves on the day. Some anxiety is normal and expected. If you start spiraling on a tough question, stop, take a few slow breaths, and reset. The clock keeps running during breaks, so use them strategically — but a 30-second mental reset can save you from a string of careless errors.

Practice before exam day. Start with our free practice exam to gauge your baseline. When you're ready to simulate the real thing — 80 questions, 4 hours, full topic coverage — upgrade to the full practice exam for detailed score breakdowns by topic.

Frequently Asked Questions

How many questions are on the Mississippi Residential HVAC exam and how long do I have?
The exam has 80 scored questions and you have 240 minutes (4 hours) to complete it.

What is the passing score?
You need 70% — at least 56 correct answers out of 80.

How much does it cost?
The exam fee is $120 per attempt, whether it's your first time or a retake. The fee is non-refundable and non-transferable.

How do I register?
First, apply with the Mississippi State Board of Contractors and wait for PSI to notify you of eligibility. Then register through the exam registration page (available 24/7) or call PSI at (855) 557-0619.

How long do I have to pass, and what if I fail?
You have 6 months from your eligibility date. During that window, you can retake the exam an unlimited number of times. If you don't pass within 6 months, you must reapply with the MSBOC.

Is the exam open book? What references can I bring?
Yes, it's open book. Approved references include: OSHA 29 CFR Part 1926, Manual J, IMC (2021), ACCA Ductulator, Modern Refrigeration and Air Conditioning (20th, 21st, or 22nd edition), HVAC Duct Construction Standards 4th edition (2020), Fuel Gas Code (2018), and Residential Oil Burners 4th Edition (2018). You must bring your own copies and cannot write in them.

Can I highlight or tab my books?
Yes — highlighting, underlining, and permanent index tabs are all permitted. You cannot write notes in the books, and temporary tabs (like Post-It notes) must be removed before the exam begins.

What ID do I need?
One valid, non-expired, government-issued photo ID that also includes your signature — driver's license, state ID, U.S. passport, military ID, alien registration card, or Canadian government ID. The name must exactly match your registration.

Are calculators allowed?
Yes — a silent, battery-operated, non-programmable calculator with no paper tape and no alphabetic keyboard.

When do I get my score?
Immediately after finishing. Pass, and you see a successful notification plus a performance summary. Fail, and you receive a diagnostic report showing your strengths and weaknesses by topic area.

Ready to Start Preparing?

The Mississippi HVAC contractor license test is thorough, but it's designed to be passed. Eighty questions, 4 hours, open book — the structure is fair if you put in the preparation. Focus hardest on Ducts, Load Calculations, Fuel Gas, and Equipment topics, get your references tabbed and highlighted, and practice under realistic conditions.

Start today with our free practice exam — 10 questions, no account required, instant results. When you're ready for a full simulation, the paid exam mirrors the real test exactly, with a detailed topic breakdown so you know exactly where to keep studying. Check the official exam bulletin for current scheduling and testing center locations.