how to get your C61 contractors license in california for air and water balancing

Air and Water Balancing Contractor: C-61/D-62 License

Table of Contents

What is a C-61/D-62 Air and Water Balancing Contractor?

A pictograph of a smart house. Energy efficiency is the ultimate goal of air balancing contractors. Air and water balancing are a critical aspect of ensuring that a home is maximize is energy usage

“An air and water balancing contractor installs any device and performs any work related to providing a specified flow of air in all types of existing heating and cooling systems and/or related to providing a specified flow of water in water piping systems” – CSLB.GOV

The D-62 is the classification required in the state of California for all persons looking to contract for air and water balancing services where the cost of labor and materials exceeds $500

Typical duties associated with water and air balancing

Five nozzles connected to a heating unit. air balancing contractors maintain various energy efficiency methods within a home

Air and water balancing are two areas of expertise often offered together but are sometimes referred to separately.

Water balancing is commonly known as hydronic balancing and air balancing is known as HVAC balancing

Hydronic balancing is a method of optimizing a building's heating and cooling system to operate at an intended indoor climate.

Some of the duties associated with water and air balancing include:

  • Air balancing and Water balancing
  • Sound and vibration testing
  • Air velocity and HEPA filter testing
  • Duct leakage inspection
  • Maintaining specified flows of water through piping systems
  • HVAC system surveying 
  • Fan performance analysis
  • HVAC Commissioning
  • Duct Pressure Testing
  • Smoke Ventilation and Extraction System Analysis
  • Door fan testing and controls calibration
  • Bidding, estimation and preparing invoices
  • Maintaining personal and job site safety

The ultimate goal of water and air balancing is to maximize optimum energy efficiency and operating cost. 

Hospital Air Conditioning Systems

Contractors that specialize in HVAC balancing can work in a variety of settings including:

  • Offices
  • Hospitals
  • Commercial Apartment Buildings
  • Restaurants

Their goal is often to achieve energy efficiency but also to help clients comply with air and water balancing standards.

So that medical facilities meet their Hospital Accreditation standards, contractors that hold the D-62 license must assess an existing HVAC system and ensure that it meets temperature requirements.

contractors applying for the hvac balancing license must know how to asses hospital air conditioning systems

However, they may function as a subcontractor under a General B as part of a larger project that calls for their specialized services.

General Contractors oversee that the subcontractor has executed their duties in adherence to code and to the specific requests of a client.

Learn more about the General Contractor License!


Logo of the contractors state license board. illustration features a paint brush, hand saw and cement truck with the letter CSLB above in white

The Contractors State License Board (CSLB) is the governing body for all contractors in the state of California. Their sole responsibility is to protect the consumer public.

They ensure that anyone charging over $500 for construction services is qualified and registered with the state. 

  • State wide task force that engages in sting operations to stop un-licensed construction activity. 
  • Getting caught contracting without a license in California is punishable with fines up to $15,000 and 6 months in the the county jail.
  • The CSLB issues the garage doors contractor license to contractors in the state of California.

C-61/D-62 License Requirements

To get the air balancing contractor license in California, you must meet the following requirements:

  • Be at least 18 years of age
  • Have a valid Driver's License or USA Issued Identification
  • Have a Social Security or ITIN #
  • Not Currently be on probation or parole

You must also have:

  • 4 Years Journey Level Experience
  • A Qualifying Individual to sign off on your experience
  • A way to prove your experience if the state asks for documentation

What is a Journey level experience?

Journeyman level experience means that you have worked unsupervised full time for an HVAC balancing company, or for a contractor that holds the D-62 License.

  • A journeyman can perform all of the duties associated with his or her trade.

The CSLB will want to see four full-time years over the last ten years.

The years do not need to be consecutive, but they do need to be four years in total. 

Signature of a Qualifying Individual

The following people may be used as Qualifying Individuals to sign off on your experience when applying for the air balancing contractor license:

  • Licensed General Contractor
  • C-61/D-62 License Holder
  • Fellow Employee (within the last 10 years)
  • Former Supervisor (within the last 10 years)
  • Business Associate
  • Fellow Journeyman
  • Union Representative

Filling out the Contractor License Application

Your Qualifying Individual will also need to provide a brief but detailed description of your knowledge and skillset.

The way this description is written will be critical to whether or not your application is accepted. For example:

“Ed is a nice guy and very experienced” is not descriptive enough for the CSLB.

The people reviewing your application will want to see something more like:

“Ed has experience conducting air velocity testing, hydronic balancing, air balancing, and fan performance analysis. 

He has tested, balanced, and calculated air circulation with adherence to OSHA standards” etc.

The description written by your qualifying individual will need to include the core skills required for the air balancing contractor license.

HVAC Balancing Work Experience

Air and water balancing contractors may need to prove their work experience when applying for the air balancing license. photo features a construction worker holding a red hat wearing a gold tool belt

You must be prepared to submit documentation supporting the experience you claim to have. 

The Contractors State License Board gives you a few ways that you can prove your experience.

They include:

  • Tax Returns
  • Check Stubs
  • Contracts
  • Material Order Invoices or Receipts

The CSLB  receives thousands of applications per month so there is a good chance they won’t document your experience.

However, if you are one of the applicants that get reviewed you will need to be ready to submit something. 

The CSLB does not accept pictures of projects.

Online Practice Exams and Study Guides

Application Processing, Fees and Criminal History

The time it takes to get your application processed and assigned a test date fluctuates throughout the year.

Typically you can expect:

  • 6-8 Week Application Processing Time
  • 3-4 Week wait for an Exam date

I have seen some situations where applicants got their test date sooner and somewhere they got their test date much later.

The most common reasons your application would get held up are:

  1. Time of year (processing time slows down during the holidays) 
  2. Criminal History 
  3. Proving Experience
  4. Mistakes on your application 

State Fees

The current state fees are:

1. $330 State Application Fee (one-time fee per application sent to the state board )

2. $200 License Activation Fee ( paid every two years )

You will also need to pay for live scan fingerprinting.

Construction Bonds 

everything you need to understand about Construction bonds and california contractor licenses

Upon passing the exam, the state board requires you to have a Contractor Bond number. A construction bond is a security deposit issued by a surety company. Bonds are designed to protect the consumer public against contractor default.

They act as protection mechanisms for clients from unethical or illegal actions performed by contractors. Bonds also ensure that subcontractors get paid for their work.

Furthermore, they ensure or that a contractor performs his duties as stated in a contract. Construction bonds protect employees, suppliers, sub-contractors or clients against a contractor's failure to abide by an agreement.

Learn more about look at Construction Bonds!

Can you get a Contractors License with a Felony in California?

a hand filling out a criminal background check form, when applying for a contractor license it is important to be 100% honest about your criminal history

Having a criminal record in no way stops you from getting the garage door license. I have personally helped guys with all types of criminal records obtain multiple licenses.

The key is, to be honest on the application, even if the felony or misdemeanor happened years ago and even if it was expunged.

BE 100% HONEST ON THE APPLICATION, because they will see everything anyway when you do fingerprinting. The CSLB handles criminal records on a case-by-case basis.

Remember, their responsibility is to protect the public.

In my experience, they are primarily concerned with criminal charges associated with Fraud, Embezzlement, or Forgery.

The Contractor License Exam

Contractor licenses are broken down into four categories:

1) A-General Engineering

2) B-General Building

3) C-Specialty classes

4) C-61 / D-Limited Specialty classes

Each category of license except the D-Limited Specialty license class requires that you pass a TRADE exam. C-61 Classification licenses do not have trade portions.

You must only pass a LAW exam.

The exam is:

  • 115 Questions on Contractor LAW
  • 3 Hours to complete
  • Multiple choice, taken on a computer
  • Closed Book

The Law Examination is divided into eight major sections:

1. Business Organization (10%)

  •  Company organization
  •  Project organization

2. Business Finances (15%)

  • Cash management
  • Budget and planning
  • Taxes
  • Financial reporting

3. Employment Requirements (12%)

  • Employment regulations
  • Evaluation and record-keeping
  • Payroll

4. Bonds, Insurance, and Liens (10%)

  • Bonds
  • Workers’ compensation insurance
  • Liens and other remedies
  • Other insurance

5. Contract Requirements and Execution (23%)

  • Bidding
  • Cost control
  • Contracts
  • Payments

6. Licensing Requirements (8%)

  • Business license
  • Contractor’s license
  • Activity regulation

7. Safety (15%)

  • Training and reporting requirements
  • General safety
  • Hazardous/unknown materials

8. Public Works (7%)

  • Prevailing wage requirements
  • Bonding requirements
  • Insurance requirements

Learn about Contractor License LAW!

CSLB Test Locations

Currently, there are CSLB testing locations in the following cities:

  • Berkeley
  • Fresno
  • Norwalk
  • San Jose
  • Oxnard
  • Sacramento
  • San Bernardino
  • San Diego
  • The CSLB will assign you a testing center based on your location. 
  • The test is not available online.
  • The CSLB allows you to bring a pre-approved translator with you.
  • The CSLB will grant you 18 months after your application is accepted to pass the law test.
  • You must wait three weeks before retaking the state exam ( $60 per retake ).

Contractor License Study Guides and Practice Tests

Two open books and a pen laying on a desk with a book shelf in the background

Some things to remember:

  • The questions you will see on the exam may use outdated terms
  • Processes may be completely different from how things are done on the job site
  • You will see questions about things you may have never done before
  • Questions will be presented to you as if you are running a large scale construction business with several employees and jobs happening all at once. 
  • Know all aspects of your trade

I have helped all types of construction professionals from various backgrounds and experience levels get licenses, and most are startled by how different the subject matter on the state exam is from their years of first-hand experience. 

Be as prepared as you possibly can. Studying just 10 minutes a day consistently can dramatically increase your chances of passing the test on your first try.

Focus on and study ONLY the information that you need to pass the Contractor License LAW exam


If you don’t have the 4 years required journeyman level experience to obtain the C-61/D-62 license for air and water balancing, not to worry.

Your journey begins here.

Energy efficiency is a billion-dollar industry with unlimited income opportunities. 

An apprenticeship program may be a great career path for you! Learn more about getting into the industry here: Apprentice vs Journeyman!

EPA Certification

When working in or around structures built before 1978, air balancing contractors may need to contain lead paint if it is present.

Knowing the correct procedures required by the Environmental Protection Agency is critical for tradesmen working in a commercial setting.

Lead paint can travel miles through air, rest on soil, and enter air ducts causing potentially fatal respiratory damage.

All tradesmen must be a source of information for their clients and community if they want referrals and repeat business.

Learn how to get an EPA Certification in 8 hours!

Blue Print Reading Course

A yellow pencil and wooden ruler laying on top of a construction blueprint. Air balancing contractors must know how to identify lines and specs on construction blueprints

Being able to read and understand blueprints is a core skill for anyone working in or around a construction site.

Identifying the structural details and dimensions of a building before making alterations is critical. Construction blueprints communicate an array of information to builders.

Being comfortable with construction blueprints is an invaluable skill for all tradesmen, but especially for an air balancing contractor who may be a part of a larger construction project. Learn how to read Blueprints!