CSLB HVAC (C-20): Online Practice Exam

What this exam covers

Practice questions for the California CSLB HVAC (C-20) license exam, delivered online and graded instantly. Per the state's classification, a C-20 contractor installs, services, and repairs forced-air heating, ventilating, and air conditioning systems, including ductwork, equipment, and refrigeration components. Works on any device, including iPad. See the official CSLB C20 classification.

Updated July 2026 · 2022 CA Codes · 653 Questions · Topic Practice

• Content Last Updated: July 24, 2026
• Code Basis: 2022 California Codes
• Question Count: 653 practice questions
• Organized By: CSLB study-guide topic categories
• Includes: This practice exam has been updated using Peerless’s vetted usable question set. Questions are organized by CSLB study-guide topic categories and include answer explanations to support full-exam review and focused topic practice. Each topic has a mini-exam to help you develop mastery.

Sample questions — Try our free practice test

1. A three pipe water system has which of the following?
   A. 1 return, 1 supply and 1 reserve · B. 1 supply, 2 returns · ✓ C. 2 supplies, 1 return · D. 2 returns, 2 supplies
2. A compressor in which compression is attained in a cylinder by rotation of a semiradial member is known as which of the following?
   A. Compressor · ✓ B. Rotary compressor · C. Hermetic compressor · D. Open type compressor
3. Which of the following describes series heating cooling circuits?
   A. Single circuits · ✓ B. Combination circuits · C. 3 way circuits · D. 4 way circuits
4. Which type of blade will produce the most pressure on air conditioning centrifugal blowers?
   A. Propeller fan · B. Forward pitched blade · ✓ C. Backward pitched blade · D. Axial flow
5. Which of the following will require the most tonnage of air conditioning?
   A. A warehouse · B. A two story apartment building · C. A residence · ✓ D. A restaurant and cocktail lounge