Nevada licenses refrigeration and air conditioning contracting through the Nevada State Contractors Board under NRS Chapter 624. The full C-21 classification — all seven subclassifications in one license — is examined by PSI in an open-book trade examination of 85 questions in 3 hours, keyed to the Uniform Mechanical Code 2018, alongside the Contractor Management Survey. The PassProfessor Nevada C-21 Refrigeration & A/C program prepares qualifying individuals for that trade examination and its companion survey.
This program is part of the expanding PassProfessor catalog — join the notify list and we’ll email you when enrollment opens.
What the full C-21 license authorises
The credential is C-21 Refrigeration and Air Conditioning under NAC 624.380, issued by the Nevada State Contractors Board (NSCB) under NRS Chapter 624, with examinations administered by PSI. Nevada licenses the contractor: there is no individual HVAC technician license category in the state’s system, and technicians work under a licensed contractor. Federal EPA Section 608 certification remains separately required for refrigerant work; it is not this examination.
The full classification’s scope, as the PSI bulletin quotes it, has three strands. First, refrigeration: construction, erection and installation of devices, machinery and units controlling air temperatures below 50°F in refrigerators, refrigerated rooms and insulated spaces, with related insulation, ducts, blowers, registers and controls — plus natural-gas lines from the unit to the existing gas line at or after the meter, and electrical service from the unit’s overcurrent device to the main panel, and not other gas or electric services. Second, air-conditioning: installation, repair, service and maintenance of equipment, devices, machinery, units and related ductwork using evaporation, refrigeration, boilers or combustion to control air temperatures in occupied structures. Third, sheet metal and repair: sheet metal selection, cutting, shaping, fabrication and installation — cornices, flashings, gutters, leaders, downspouts, pans, kitchen equipment, ducts, louvers, patented chimneys and metal flues — and repair of parts of existing units and systems.
A full classification C-21 license authorises all subclassification work, and C-21 work is not incidental or supplemental to other work.
The examinations at a glance
| Item | Verified position |
|---|---|
| Program | Nevada C-21 Refrigeration & A/C — the full C-21 trade examination plus the Contractor Management Survey |
| Regulator | Nevada State Contractors Board (NSCB), under NRS Chapter 624 and NAC 624 |
| Vendor | PSI — classification and management bulletins, both updated March 25, 2026 |
| Trade examination | 85 questions · 3 hours (180 minutes) · OPEN BOOK |
| Trade passing standard | A minimum passing score of 60 of 85, stated as a raw count in the bulletin |
| Contractor Management Survey | 60 scored items · 120 minutes · OPEN BOOK |
| Survey passing standard | 45 of 60 / 75% |
| Tested code | Uniform Mechanical Code, 2018 — examination layer only; no statewide field edition |
| Experience gate | At least 4 years within the 15 years immediately preceding application |
| Administrator note | PassProfessor is independent and is not affiliated with the Nevada State Contractors Board |
Seven subclassifications under one license
NAC 624.380 divides C-21 into seven subclassifications; the roster below maps what the full license covers.
C-21a Refrigeration — control of air temperatures below 50°F in refrigerators, refrigerated rooms and insulated spaces, with the related connections described above. C-21b Air-Conditioning — equipment using evaporation, refrigeration, boilers or combustion to control air temperatures in structures, including related ductwork and controls. C-21c Sheet Metal — sheet-metal fabrication and installation, including metal roof systems, but not equipment using refrigeration as an integral part. C-21d Maintenance — repair and replacement of parts of existing units, such as compressors, motors, relays, coils and heat exchangers, but not complete condenser assemblies on remote systems, air handlers, or work altering a system’s design. C-21e Solar Air-Conditioning — collectors, piping and storage for converting solar energy to temperature-control energy. C-21f Chilled and Hot Water Systems — boilers, chillers, coils, cooling towers, piping, pumps, storage tanks and valves for producing and transferring water for temperature control. C-21g Industrial Piping — piping and equipment transmitting water, steam, gas, chemicals, food and other substances for industrial uses.
This program prepares candidates for the full C-21 examination, not for any single subclassification sitting.
Two examinations, two different kinds of standard
The C-21 trade examination carries 85 scored questions in 3 hours (180 minutes), open book. Its published outline runs: Piping 6; Insulation 1; Hangers and Supports 3; Sound, Vibration and Seismic Control 1; Heating and Cooling Principles 3; Refrigerants and Refrigeration 7; Load Calculations 6; Testing, Adjusting and Balancing 3; Controls 5; Machine Room 1; A/C and Heat Pump Equipment 4; Furnaces and Heaters 4; Hydronics 2; Chimneys, Flues and Vents 5; Combustion Air 2; Fuel Systems 10; Ducts 6; Evaporative Cooling 2; Chillers 3; Solar 4; Ventilation and Exhausts 3; Safety 4. Separately from the scored 85, non-scored experimental items, between one and ten, may be added and count against the examination time; the two counts are never merged into one total.
The passing standard for the trade examination is published as a raw count: a minimum passing score of 60 of 85. The bulletin states it in that form, and this page states it in that form only. Candidates should distrust any source that restates it in another form.
The Contractor Management Survey (CMS) is the companion examination every qualifier takes. It carries 60 scored items plus 3 non-scored items, stated separately in exactly that form, in 120 minutes plus 6 minutes for the non-scored items, open book; Financial Management and Licensing are its largest outline areas, and the companion guide sets out its full outline. Its passing standard is published in its own form: 45 of 60 / 75%. The two portions keep their own standards; no combined figure governs them together.
Both sittings share PSI’s administration rules. Arrive 30 minutes early with one form of photo identification; scores are reported immediately, with a diagnostic report by subject area on failure. Cancelling without forfeiture requires notice 2 days before the appointment, and voicemail is not an acceptable cancellation. References may be highlighted, underlined and indexed beforehand but never written in, with permanent tabs only, and a silent, non-printing, non-programmable calculator is allowed. Fingerprints are required with the application, accompanied by a cashier’s check payable to the Nevada Highway Patrol equal to the Central Repository and FBI charges — the rule sets no fixed dollar amount for that check.
The tested layer: UMC 2018, and no statewide field edition
Nevada’s code position must be stated exactly. There is no statewide field-code edition for this trade in Nevada: nothing in NRS Chapter 624 or NAC 624 adopts a single statewide mechanical code, and local jurisdictions adopt their own editions. No adopted-edition statement appears on this page, because none exists to state.
What exists is an examination layer. The trade examination keys the Uniform Mechanical Code, 2018 (IAPMO), and code questions are based only on that listed edition regardless of which edition a candidate’s local jurisdiction enforces. Preparation built on a different UMC edition must be re-keyed to UMC 2018 before it can be trusted here.
The allowed references for the trade examination are: the Uniform Mechanical Code, 2018; NFPA 54 National Fuel Gas Code, 2012; Modern Refrigeration and Air Conditioning, 19th or 20th edition; HVAC Duct Construction Standards, Metal and Flexible, 2005 (SMACNA); Manual N Commercial Load Calculation, 5th edition, 2008 (ACCA); Solar Water and Pool Heating Design and Installation Manual, 1997 (Florida Solar Energy Center); and Evaporative Air Conditioning Handbook, 3rd edition, 1997 (Watt & Brown). OSHA 29 CFR Part 1926 is not an allowed reference for this examination. For the CMS, the only allowed reference is PSI’s Construction Business and Law Manual for Nevada. No NASCLA edition serves Nevada.
Who may sit: experience, the qualifying person, and the application
The experience gate is set by NRS 624.260: within the 15 years immediately preceding the filing of the application, the applicant must have at least 4 years of experience as a journeyman, foreman, supervising employee or contractor in the specific classification applied for. Training in an accredited program, or a Board-accepted equivalent, may satisfy not more than 3 years of that requirement.
The qualifying person must be a bona fide member or employee of the applicant, make the technical and administrative decisions, hold authority to hire, superintend, promote, transfer, lay off, discipline and discharge, and devote himself or herself solely to the business. If the qualifying person ceases to be connected with the licensee, the Board must be notified in writing within 10 days; the license remains in force for a Board-set period not exceeding 30 days, and failure to notify brings automatic suspension.
The application is filed separately for each classification under NAC 624.590: experience documented by four or more certificates of work experience on the Board’s form (or the rule’s alternatives), a financial statement under NAC 624.593 with bank-confirmed information, and fingerprint cards with background authorisation. An application is deemed withdrawn if not completed within 6 months, and the qualifying person must pass the examinations within 6 months after filing. Examination waivers exist through the Board’s endorsement mechanism, worked through in the companion guide. This page names no endorsing states; the Board publishes that list.
The monetary limit and the edges of the license
Every Nevada license carries a monetary limit: the maximum the licensee may undertake on one or more construction contracts on a single construction site or subdivision site for a single client, set on statutory factors. A bid or contract outside the scope of the license or exceeding the monetary limit is void, and the license number and the monetary limit must appear in all bids and contracts. Single-project increases follow their own request-and-approval rule, set out in the companion guide.
Nevada’s small-work exception has a carve-out that decides this trade’s boundary: work in a classification the contractor is not licensed in can be excepted only where it is worth less than $1,000 including labour and materials and no permit is required — and that exception never applies to plumbing, electrical, refrigeration or air-conditioning work.
Fees, bond and the residential fund — separate instruments
PSI examination fees (vendor layer). One examination portion is $95. Two portions are $140, only when the second examination is the CMS; two trade examinations are $95 each. Fees are non-refundable.
Board fees (rule layer, NAC 624.130). The application for a classification in which the applicant is not licensed is $300. Issuing or renewing a license is $600. Late filing of an active-license renewal application is $150. The same schedule sets ancillary instruments — an inactive license at $300, a $200 cash-deposit administrative fee, a $250 change of qualified person — each charged as its own instrument, never merged into a single licensure total.
Bond (a licensure instrument, not a fee). Before issuance, the licensee must post a surety bond from a surety authorised in Nevada whose long-term debt is rated “A” or better, or a cash deposit in its place. The Board fixes the amount by the contractor’s financial and professional responsibility and the magnitude of operations, at not less than $1,000 nor more than $500,000. The bond is continuous; a surety may cancel on 60 days’ notice by certified mail, and the license is then suspended or revoked unless an equivalent bond or deposit is furnished.
Recovery Fund (residential layer only). Residential work carries a biennial Recovery Fund assessment set by monetary limit — $200, $500 or $1,000 by tier — under NRS 624.470 and following. Those are residential-contractor figures, not C-21 commercial fees; the guide records the tier thresholds.
Renewal, continuing education and retakes
Each license expires 2 years after the date it is issued, under NRS 624.283. Under NAC 624.630 the completed renewal application is due not later than the last day of the month in which the license expires, with the $150 late fee above for late filing. A license not renewed on or before its renewal date is automatically suspended; it may be reinstated within 6 months on a renewal application, the renewal fee and a Board-fixed reinstatement fee. A license not reinstated within that window may be cancelled, after which a license issues only on an original application. Changes in address or personnel must be reported in writing within 30 days.
On continuing education: neither NRS 624.283 nor NAC 624.630 imposes any continuing-education requirement for renewal of this license.
Retakes run in two layers. At the PSI layer, a candidate who fails must wait 2 weeks before retaking each portion. At the rule layer, under NAC 624.600, failing a third time voids the application: the candidate must re-apply directly with the Board 30 days or more after the date of the last examination.
What the PassProfessor program will cover
Our catalog now includes preparation built for the full C-21 sitting: the trade outline weighted as the bulletin weights it, with Fuel Systems at its centre; the Uniform Mechanical Code 2018 as the keyed code, in a state with no statewide field edition; the CMS as a companion sitting with its own reference and its own standard; and the qualifying-person and monetary-limit rules. Every item is written from scratch against the primary sources recorded for this page. The companion guide — Nevada C-21 Refrigeration & A/C Exam Guide — works through the route in full depth.
Independence, stated plainly. PassProfessor is an independent preparation provider, not affiliated with the Nevada State Contractors Board or PSI. The Board alone licenses.
Tell me when enrollment opens. The Nevada C-21 Refrigeration & A/C program is in the works and enrollment is not yet open. Leave an email address to be notified when it is ready — and only about this program.
Frequently asked questions
Who issues the C-21 license in Nevada?
The Nevada State Contractors Board (NSCB), under NRS Chapter 624 and NAC 624.
What does the full C-21 license cover?
All seven subclassifications — refrigeration, air-conditioning, sheet metal, maintenance, solar air-conditioning, chilled and hot water systems, and industrial piping.
How is the trade examination structured?
85 scored questions in 3 hours, open book, across 23 outline areas with Fuel Systems the largest at 10. Between one and ten non-scored experimental items may be added and count against the time.
What score passes the trade examination?
A minimum passing score of 60 of 85 — the raw count in which the PSI bulletin publishes the standard.
What score passes the Contractor Management Survey?
45 of 60 / 75%, on the survey’s 60 scored items.
Which code is examined, and which code applies in the field?
The examination keys the Uniform Mechanical Code, 2018. Nevada has no statewide field-code edition for this trade; local jurisdictions adopt their own editions.
How much experience is required?
At least 4 years as a journeyman, foreman, supervising employee or contractor in the classification, within the 15 years immediately preceding the application. Accredited training may satisfy not more than 3 years of it.
What do the examinations cost?
PSI charges $95 for one portion and $140 for two portions when the second is the Contractor Management Survey. Board fees are separate: a $300 application and $600 to issue or renew a license.
Is PassProfessor affiliated with the NSCB?
No. PassProfessor is an independent preparation provider; the Board alone licenses contractors.
When does enrollment open?
The program is in the works and enrollment is not yet open. Leave an email address on this page to be notified.