Nevada's C-21 is the full refrigeration and air-conditioning classification, issued by the Nevada State Contractors Board (NSCB) and covering every C-21 subclassification. Getting it means a qualified individual with four years of experience in the classification, an application with a financial statement, two PSI exams — the C-21 trade exam and the Construction Management Survey (CMS) — and a bond set by the Board. This guide uses only what the NSCB, Nevada law and PSI's current bulletin publish, including exactly which HVAC exam PSI offers in Spanish.
NRS 624.020 defines a contractor broadly: anyone who undertakes or offers to construct, alter, repair, add to, subtract from, improve, move, wreck or demolish any building or other structure, including subcontractors and specialty contractors, and construction managers paid a professional fee. The Board requires the license before you contract — before you bid, offer to engage or negotiate a price. The small-job exemption in NRS 624.031(6) is narrow: work to repair or maintain property worth less than $1,000 in labor and materials, and only if no building permit is required, the work is not the type done by plumbing, electrical, refrigeration, heating or air-conditioning contractors or by another classification the Board treats as significantly affecting public health and safety, and it is not part of a larger project worth $500 or more or split into smaller contracts to evade the law.
NAC 624.380 grants classification C-21 in refrigeration and air-conditioning. A C-21 holder may perform any work authorized for its subclassifications: C-21a Refrigeration, C-21b Air-Conditioning, C-21c Sheet Metal, C-21d Maintenance, C-21e Solar Air-Conditioning, C-21f Chilled and Hot Water Systems and C-21g Industrial Piping. The regulation adds that C-21 work is not incidental or supplemental to the work of any other specialty contractor. PSI's bulletin summarizes the scope: refrigeration below 50°F in refrigerators, refrigerated rooms and insulated spaces; equipment that uses evaporation, refrigeration, boilers or combustion to control air temperatures where people live, work or assemble or animals are kept, with its ductwork and controls; sheet-metal work such as ducts, flashings, gutters and metal flues; the gas line from the unit to the existing line at or after the meter; and the electrical service from the unit's overcurrent device to the main panel — but not other gas or electric services.
The subclassifications are separate, narrower licenses with their own PSI exams. The one most often weighed against the full C-21 is C-21b Air-Conditioning — installing, repairing, servicing and maintaining equipment and ductwork that use evaporation, refrigeration, boilers or combustion to control air temperatures in structures, with their humidity and thermostatic controls. HVAC work never fits the small-job exemption above: NRS 624.031(6) excludes refrigeration, heating and air-conditioning work at any price.
Nevada licenses the business — the license belongs to the business, not to the qualifying person — but every license rests on a trade qualified individual. Under NRS 624.260, as the Board's requirements page explains, that person can be an owner, officer, member, manager or employee, must be a bona fide member or employee of the company, and must be actively engaged in its contracting business. The experience rule is specific: within the fifteen years immediately before the application is filed, at least four full years as a journeyman, foreman, supervising employee or contractor in the specific classification requested — here, the C-21 classification. The application also lets one company split the role: a management qualifier, who must pass the construction management exam, and a trade qualifier, who meets the experience and trade-exam requirement — or one person who does both.
The Board accepts three kinds of proof: four Certification of Work Experience forms for each trade qualifier, filled out by current or former employers, general contractors, subcontractors or customers — one per company, and relatives only if they were your employer — which together must add up to at least four full years (1,460 days), though no single certificate has to cover all four; a current master's certification issued by a government agency in a substantially similar discipline; or proof of transferable military experience and training. Every qualifier also files a Resume of Experience, and self-employed experience needs a list of customers with their addresses and phone numbers. There is no education requirement, but training in a program at an accredited college, university or equivalent program accepted by the Board can count for up to three of the four years, documented with apprenticeship certificates or transcripts.
The application goes to the NSCB with a nonrefundable $300 application fee and a principal's signature, together with the experience documents, a resume, copies of government IDs, and a background disclosure and fingerprint form for every person listed; PSI's bulletin adds that each applicant submits fingerprints for a state and national fingerprint-based criminal history check. Examination fees are separate and are paid to PSI, not to the Board.
A financial statement is required whatever the size of your work, because the Board puts a monetary limit on every license — under NRS 624.220, the maximum contract you may undertake on one or more construction contracts on a single construction site or subdivision site for a single client. The limit you request decides the kind of statement: at $25,000 or less, a CPA-prepared statement, the Board's own business or personal financial statement form, or an accounting-software balance sheet with an affidavit; above $25,000 and below $500,000, a CPA-compiled statement current within six months, or a reviewed or audited one current within a year; from $500,000 to below $1,000,000, a compiled statement with full disclosures, or a reviewed or audited one; at $1,000,000 or more, reviewed or audited by an independent CPA. A Bank Verification Form completed by your bank goes with it.
The bond comes last. The Board fixes the amount at license approval — anywhere from $1,000 to $500,000, depending on the type of license, the monetary limit, financial responsibility, experience and character — and you post it as a surety bond or a cash deposit before the license issues. A cash deposit carries a $200 biennial administrative fee and is held for two years after the license ends.
The NSCB requires every applicant to pass the CMS business-and-law exam and a trade exam for the classification, both administered by PSI. PSI's “C” Classification bulletin (updated 3/25/2026) sets the C-21 Refrigeration and Air Conditioning Contractor exam at 85 questions, 3 hours and a minimum passing score of 60. It is open book with two references allowed in the room: the 2018 Uniform Mechanical Code and NFPA 54, the National Fuel Gas Code, 2012 edition. Code questions follow the listed edition only.
The outline spreads 85 items over 22 areas. The heaviest are Fuel Systems 10 and Refrigerants and Refrigeration 7, then Piping, Load Calculations and Ducts at 6 each, Chimneys, Flues and Vents and Controls at 5, and A/C and Heat Pump Equipment, Furnaces and Heaters, Solar and Safety at 4; the rest — hangers and supports, testing and balancing, heating and cooling principles, chillers, ventilation and exhausts, combustion air, hydronics, evaporative cooling, insulation, machine room, and sound, vibration and seismic control — carry one to three each. The books behind many of those items may not be brought in: 29 CFR Part 1926, Modern Refrigeration and Air Conditioning, SMACNA's HVAC Duct Construction Standards, ACCA Manual N for commercial load calculation, a solar water and pool heating manual and an evaporative air-conditioning handbook. Bring your own copies of the allowed books. You may highlight, underline and index them before the exam and use permanent tabs, but you may not write in them, sticky notes must come out, and loose papers are confiscated. A silent, non-printing, non-programmable calculator is allowed.
The CMS is 60 scored questions plus 3 unscored, 120 minutes, 45 correct (75 percent) to pass, open book with PSI's Construction Business and Law Manual for Nevada — see our Nevada CMS guide.
NAC 624.600 lets the Board waive the exam for someone who passed an exam offered by an endorsing state the Board has approved, or a NASCLA-accredited exam the Board finds substantially equivalent. Endorsement requires active licensure in the endorsing state for the past four years with no discipline, a Request for Verification of Licensure completed by that state, and a match on the Board's State Equivalency Chart; if that state has no equivalent trade exam, you take Nevada's. The Board's pages also describe a waiver for qualifiers who recently served on another Nevada license in the same classification, but they state the look-back period differently from page to page, so confirm yours with the Board. It reserves the right to require an exam of any applicant.
In a news release dated December 9, 2025, the NSCB announced that PSI offers Spanish-language exams for 13 classifications and the Construction Management Survey, and PSI's current bulletin lists the same exams. The HVAC entry on that list is C-21b, Air Conditioning — not the full C-21 exam and not the other C-21 subclassifications. So, as published today, the full C-21 trade exam is taken in English; the C-21b subclassification exam and the CMS can be taken in Spanish. To switch a listed exam from English to Spanish, PSI's bulletin says to call PSI at (855) 205-5827 or email examschedule@psionline.com.
If you are weighing C-21b for that reason, know what it is: a narrower license — air-conditioning only, without the refrigeration, sheet-metal, chilled-water and other subclass scopes — with its own exam of 60 questions, 42 to pass, 2 hours, open book with the same 2018 UMC and 2012 NFPA 54. Every subject area on the C-21b outline also appears on the C-21 outline, but the weights differ.
You cannot book an exam until the Board has your application and has verified the experience. It then issues an Examination Eligibility form with a Candidate ID — the application packet says it is mailed to the business's mailing address, not the qualifier's home — and you register with PSI online at test-takers.psiexams.com/nvcon or by phone. PSI charges $95 for one examination portion and $140 for two when the second one is the CMS (two trade exams are $95 each); registration fees are not refundable or transferable and expire with your eligibility. Cancel or reschedule at least two days before the appointment, arrive 30 minutes early, and bring one valid, unexpired government photo ID whose name matches your registration — otherwise the fee is forfeited.
Tests run on computer at PSI centers in Las Vegas, Reno and Elko, and PSI's Nevada exams can also be taken at PSI sites in other states. Your score is given when you finish; a failing report shows strengths and weaknesses by area. After a failure you wait two weeks before retaking that portion. NAC 624.600 allows three attempts and requires the qualifier to pass within six months after the application is filed; a third failure voids the application, and you may apply again with a new application and fee 30 days or more after the last exam.
NAC 624.130 sets the Board's fees: $600 to issue or renew a license, and $150 for filing an active license's renewal late. Under NRS 624.283 a license expires two years after it is issued, and a license not renewed on or before its renewal date is automatically suspended. The bond must stay continuous the whole time: a surety can cancel only on 60 days' notice to the Board, and failing to keep the bond in force is cause to suspend or refuse to renew the license.
A Nevada license does not replace EPA Section 608 certification. Under 40 CFR Part 82, Subpart F, technicians who maintain, service, repair or dispose of appliances that could release refrigerant into the atmosphere must be certified, and the licensed contractor's technicians need it regardless of the state license. Our EPA 608 guide and free EPA 608 practice test cover Core and all three types.
The Board is plain about preparation: it does not recommend or endorse any licensing school, it offers no practice exams of its own, and it points candidates to the reference list in each content outline. For C-21 the two books in the room — the 2018 UMC and NFPA 54 — carry the code side, so tab them for venting, combustion air, gas piping and duct rules; Fuel Systems alone is 10 items. Refrigeration cycle, load calculation and duct sizing come from study, because their source books stay outside.
LICENA's Nevada C-21 practice bank is 500 questions in five blocks mapped to PSI's 22 C-21 subject areas, every answer explained, in English, Spanish and Russian, with a free sample and no sign-up. It follows the full C-21 outline, not the C-21b one. The Nevada CMS bank covers the business-and-law exam.
Ready to practice for the exams? The Nevada C-21 Refrigeration & AC practice bank on LICENA: 500 questions mapped to PSI's C-21 subject areas, with a written explanation on every answer, in English, Spanish and Russian. The sample is free — no sign-up.
Try the free practice test → Nevada CMS practice