Tennessee CMC-C Mechanical HVAC/Refrigeration Contractor

Tennessee CMC-C HVAC/Refrigeration Contractor Exam: Complete 2026 Study Guide

You've got the field experience. Now you need the license. The Tennessee CMC-C exam is the gateway to operating as a licensed mechanical HVAC/refrigeration contractor in Tennessee — and passing it opens doors to bigger jobs, better contracts, and the ability to pull your own permits. This guide covers exactly what's on the Tennessee CMC-C exam, what books to bring, how to study smart, and what to expect on test day. Take a free practice exam right now if you want to see where you stand before reading another word.

Tennessee CMC-C Exam Overview

The Tennessee HVAC refrigeration contractor exam is administered by PSI. Here are the numbers you need to know:

• Questions: 100 scored questions
• Time limit: 260 minutes (4 hours, 20 minutes)
• Passing score: 73 correct out of 100 (73%)
• Format: Open book — you bring your own approved references
• Location: PSI testing centers

The exam is open book, but don't let that fool you into thinking you can wing it. You'll spend too much time hunting through unfamiliar pages. The candidates who pass have their books tabbed, highlighted, and memorized well enough that they only open them to confirm a number — not to learn a concept on the spot.

Register through the exam registration page or check the official exam bulletin for the full candidate handbook. You can also reach PSI at (855) 868-1882, Monday–Friday 6:30 am–9:00 pm CT, Saturday–Sunday 8:00 am–4:30 pm CT.

Topics Covered on the Tennessee CMC-C Exam

The exam covers ten topic areas. Here's how they break down by question count — this tells you where your study hours should go.

Piping and Ducts carry the most weight at 14 questions each — together that's 28% of your exam. Know those cold. The six topics at 10 questions each are all equally important. Electrical and Load Calculation are lighter, but five easy points on Load Calculation can make the difference between passing and retaking.

Sample Questions from the Tennessee CMC-C Exam

Here are five real-style questions from the TN mechanical contractor license test. Work through them — then check your answers with our free practice exam.

Question 1 — Piping (Medium)
You are selecting pipe for a hydronic heating panel system where the piping will be embedded in a concrete floor slab. Which of the following is an approved piping material for this application?

• A) Type M copper tubing
• B) Schedule 40 PVC pipe
• C) Type L copper tubing
• D) ABS plastic pipe

Question 2 — Piping (Medium)
In a two-pipe steam heating system, what device is installed in the return piping to block the flow of steam while allowing condensed water to pass back to the boiler?

• A) Backflow preventer
• B) Zone valve
• C) Steam trap
• D) Air vent

Question 3 — Combustion Air, Chimneys, Flues and Vents (Medium)
During a safety inspection of an existing non-direct-vent appliance installation, the inspector finds that the upper horizontal combustion air duct slopes downward toward the air supply source. What action is required?

• A) Add a condensate drain to the duct
• B) Install a booster fan in the duct
• C) Correct the duct slope direction
• D) Increase the duct diameter by one size

Question 4 — Ducts, Ventilation and Exhaust (Hard)
You are building an air handling unit casing. The drain line from the coil section operates under negative static pressure. The water seal on the drain must be at least how much greater than the maximum operating negative pressure in the chamber?

• A) 3 in. wg
• B) 1 in. wg
• C) 4 in. wg
• D) 2 in. wg

Question 5 — Fuel and LP Gas (Hard)
When sizing a venting system for a single draft-hood-equipped appliance using Type B vent, and the vent system includes three 90-degree elbows, by what percentage must the maximum vent capacity listed in the tables be reduced?

• A) 15 percent
• B) 20 percent
• C) 10 percent
• D) 5 percent

Know the answers? Try the free practice exam to test yourself across all ten topic areas.

What Types of Questions to Expect

Here's what the exam actually asks you to do, topic by topic — along with the practice questions we offer in each area.

Electrical Knowledge, Motors, and Controls (71 practice questions): Ohm's Law calculations, horsepower and kVA conversions, reading ladder and pictorial circuit diagrams, motor sizing, and control circuit logic.

Piping – Refrigeration, Hydronic, Steam and Process (58 practice questions): Material selection for embedded piping, steam trap identification, ACR tubing applications, brazing and flaring requirements, hydronic piping design, and process piping specifications.

Heating and Cooling Principles and Theory (73 practice questions): Compression refrigeration cycle operation, gas laws, pressure-temperature relationships, heat transfer fundamentals, and psychrometrics.

Heating and Cooling Equipment and Components (75 practice questions): Compressor types and configurations, condenser and evaporator selection, metering device operation, and refrigeration cycle component functions.

Refrigerants and Refrigeration (68 practice questions): Refrigerant classification (CFC, HCFC, HFC, HFO, HC), ODP and GWP, gauge manifold use, vacuum pump procedures, recovery and charging, and service valve operation.

Fuel and LP Gas (36 practice questions): Gas piping material selection, pipe sizing calculations, combustion air requirements, pressure requirements, and venting system design including elbow derating.

Combustion Air, Chimneys, Flues and Vents (30 practice questions): Vent connector materials and clearances, combustion air duct slope requirements, chimney sizing, and venting methods for various appliance categories.

Ducts, Ventilation and Exhaust (78 practice questions): Duct pressure classifications, material selection, gauge and reinforcement requirements, sealing and leakage testing, drain seal sizing, and exhaust system design.

Load Calculation (27 practice questions): HTM and U-value calculations for windows and walls, CLTD for opaque panels, infiltration estimation methods, duct load adjustments, and Manual J design conditions.

Safety, Fire and Smoke Protection (51 practice questions): Fire and smoke damper ratings, placement requirements, lockout/tagout (LOTO) procedures, and OSHA 29 CFR 1926 compliance.

In total, we offer 567 practice questions across all ten topics. The full practice exam mirrors the real Tennessee CMC-C exam — 100 questions, 260-minute limit, same topic breakdown — with a detailed score report so you can see exactly where you're weak.

Required Study Materials

This is an open-book exam, so you need the right books — and you need to know them well.

Required references:

• Modern Refrigeration and Air Conditioning — Your primary source for refrigeration principles, compressor types, refrigerant classification, and charging procedures. Know this book.
• IMC 2021 — Covers ducts, mechanical equipment, and piping. Tab Chapters 5, 6, 12, and 13.
• IFGC 2021 — All fuel gas and venting questions pull from here. Tab the pipe sizing tables, combustion air sections, and vent tables before you walk in.
• Manual J – Residential Load Calculation — Used for the five Load Calculation questions. Work a few examples so the format is familiar.
• HVAC Duct Construction Standards — SMACNA duct gauge and reinforcement tables. Tab them.
• Pipefitter's Handbook — Hydronic and steam piping reference.
• Ugly's Electrical References 2020 — Fast lookup for motor and wiring questions.
• OSHA 29 CFR 1926 — LOTO procedures and construction safety rules.

Recommended tools:

• Sharpie Highlighters — Highlight key tables, code sections, and formulas. The ink resists smearing, which matters when you're working fast.
• Redi-Tag Permanent Colored Tabs — Permanent adhesive, color-coded by topic. The exam allows tabbed books; use this to your advantage.
• ACCA Ductulator (Duct Slide Rule) — An air duct sizing calculator is on the approved reference list. Bring one.

Study Tips for the Tennessee CMC-C Exam

Lead with the heavy topics. Piping and Ducts are 14 questions each. Get those right and you've already built a strong foundation toward 73.

Tab your books before test day. Use Redi-Tag permanent tabs on every major table you'll need: IFGC pipe sizing, combustion air methods, vent tables, SMACNA gauge tables, and IMC Chapters 5 and 6. Color-code by code book so you're not hunting.

Refrigeration, equipment, and refrigerants are 30 questions from Modern Refrigeration. Learn the refrigeration cycle, metering devices, compressor types, and refrigerant classifications well enough that you don't need to open the book. Confirm numbers, don't look up concepts.

Fuel and LP Gas plus Combustion Air are straight code lookup — 20 questions total, all in the IFGC. If your book is tabbed right, these are fast points.

Do a few Manual J examples. Load Calculation is only 5 questions, but they require a specific process. Run through HTM calculations and infiltration methods once so the format isn't new on exam day.

Bring a silent, non-programmable calculator. No paper tape, no alphabetic keyboard. You'll need it for electrical formulas and load calc math.

Pace yourself. 260 minutes for 100 questions is 2 minutes 36 seconds per question. Flag anything that requires long code lookups, answer what you know, and come back.

Frequently Asked Questions

How much does the Tennessee CMC-C exam cost?
The Trade exam costs $57, and the Business & Law portion is also $57 — each charged separately. Fees are not refundable or transferable, so make sure you're ready before you register.

How many questions are on the CMC-C exam and how long do I have?
The CMC-C Trade exam has 100 scored questions. You have 260 minutes to complete it.

What is the passing score?
You need to answer 73 out of 100 questions correctly — that's 73%. Every point counts, so don't leave anything blank.

How do I register for the exam?
Register online at the exam registration page or call PSI at (855) 868-1882. Phone support runs Monday–Friday 6:30 am–9:00 pm CT and Saturday–Sunday 8:00 am–4:30 pm CT.

Is the CMC-C exam open book?
Yes. You bring your own approved references to the testing center. Books may be highlighted, underlined, and tabbed with permanent tabs, but no writing in the margins.

What reference books are allowed?
Approved references include the IMC 2021, IFGC 2021, Manual J (Eighth Full Edition), Pipefitter's Handbook (3rd Edition), Modern Refrigeration and Air Conditioning (21st or 22nd edition), HVAC Duct Construction Standards (2020), Ugly's Electrical References (2011, 2014, or 2020), Carrier System Design Manual Part 3, an air duct sizing calculator wheel or slide, and OSHA 29 CFR Part 1926.

Can I use a calculator?
Yes — a silent, nonprinting, non-programmable calculator is allowed. No paper tape, no alphabetic keyboard.

What ID do I need?
One valid, unexpired, government-issued photo ID that also has your signature — a state driver's license, state ID, U.S. passport, U.S. military ID, U.S. Alien Registration Card, or Canadian government-issued ID. Must be a permanent physical card; temporary or paper versions are not accepted.

How soon can I retake the exam if I fail?
You can't schedule a new appointment the same day you tested. If you fail on a Monday, call Tuesday and you could potentially retest as early as Wednesday, depending on seat availability.

What if I miss my appointment or cancel late?
If you don't cancel at least 2 days before your scheduled exam, fail to appear, arrive late, or can't provide proper ID, your registration is invalid and you forfeit your fee. You also forfeit the fee if you don't test within one year of PSI receiving your payment.

Get Your Tennessee CMC-C License

The Tennessee CMC-C exam is 100 questions, 260 minutes, open book, and requires 73 correct to pass. It's achievable — with the right books, tabbed and highlighted, and enough practice that you're confirming answers instead of learning material under the clock.

Start now with our free practice exam — 10 questions, no account required, no cost. See where you're strong and where you need work. When you're ready to do a full timed simulation with all 100 questions and a detailed topic breakdown, upgrade to the full practice exam.

Check the state licensing website for application requirements, and register for the exam at the official exam bulletin when you're ready to schedule your date.