A bad HVAC hire gets expensive fast - missed permits, poor airflow, refrigerant mistakes, and a quote that changes after the work starts. When your furnace, heat pump, or AC is down in the Bay Area, the low bid can be tempting. Ask these questions before you approve the work.
Start with the license and insurance
Question 1: Do you hold an active California C-20 HVAC contractor license?
In California, HVAC work requires a CSLB contractor license when the total labor and materials are $500 or more. The HVAC classification is C-20, Warm-Air Heating, Ventilating and Air-Conditioning Contractor.
Do not just take the tech's word for it. Look up the company on the CSLB Check a License tool before you approve a repair, replacement, or diagnostic job. The record can confirm:
- License status
- Business name
- License classification
- Bond status
- Workers' compensation status
The name on the quote should match the licensed business name. If the estimate has one name, the truck has another, and the license belongs to a third, slow down.
This matters in Pleasanton, Dublin, Livermore, San Ramon, and the rest of the Tri-Valley. If the contractor is not properly licensed, you may be the one dealing with failed inspections, unsafe work, or no real warranty support.
If you want licensed HVAC service in the Bay Area, start by checking the C-20 license before approving the work.
Question 2: Can you provide current insurance and workers' compensation coverage?
A California contractor license bond is not the same as insurance. California contractor license bonds are $25,000, and they are mainly there to protect consumers from certain contractor violations. They do not replace general liability insurance if property damage happens.
Workers' compensation matters too. Under California SB 216, C-20 HVAC contractors must carry workers' compensation insurance even if they have no employees. You can see workers' comp status on the CSLB license record.
Why should you care? If someone gets hurt in your attic, on your roof, or while moving equipment, you do not want a coverage fight at your address. If a furnace, condenser, duct system, ceiling, or electrical component is damaged during the job, you want the contractor's insurance to respond.
Check the people doing the work
Question 3: Are your technicians trained and certified for this equipment?
NATE stands for North American Technician Excellence. It is a third-party HVAC certification, not a California contractor license. A contractor still needs the proper CSLB license, but NATE can be a useful sign that the technician has tested technical knowledge beyond basic field exposure.
Training matters because equipment has changed. A tech who only knows old single-stage gas furnaces may struggle with newer variable-speed heat pumps, inverter systems, communicating controls, and ductless mini splits.
Bay Area homes are mixed. You may have a 1970s ranch in Pleasanton with undersized returns, a Fremont home with a tight furnace closet, or a Livermore house that added square footage after the original AC was installed. The person working on the system needs to understand both the equipment and the house.
Question 4: Are technicians EPA Section 608 certified for refrigerant work?
EPA Section 608 certification is required for technicians who service, maintain, repair, or dispose of equipment that could release regulated refrigerants. That includes AC and heat pump work where refrigerant circuits are opened, charged, recovered, or repaired.
If someone is adding refrigerant without checking for leaks, pressures, temperature readings, airflow, and manufacturer charging procedures, that is not proper service. It is guessing with expensive parts.
A refrigerant issue should be diagnosed. Low charge usually means there is a leak or another fault. Topping off the system without finding the cause can waste money and leave you with the same problem on the next hot day.
Make them explain the diagnosis and sizing
Question 5: What did you actually test before recommending repair or replacement?
A real diagnosis is more than pointing at the age of the unit. Before recommending a major repair or replacement, the contractor should be able to explain what was tested and what the readings showed.
For cooling and heat pump calls, that may include:
- Thermostat operation
- Air filter condition
- Supply and return airflow
- Static pressure
- Refrigerant pressures and temperature readings
- Electrical readings at capacitors, contactors, motors, and boards
- Condensate drainage
- Outdoor coil and indoor coil condition
For gas furnaces, the tech should also consider combustion safety, venting, ignition, flame sensing, gas pressure where needed, and safety controls.
If the answer is just "it's old" or "you need a new one," push for more detail. Old equipment can fail, but the recommendation should be tied to findings.
Question 6: If replacing equipment, will you perform a load calculation and check the ductwork?
Replacing a 3-ton AC with another 3-ton AC sounds simple, but it can be wrong. Homes change. Windows get upgraded. Attics get insulation. Rooms get added. Ducts get crushed, disconnected, or altered.
A contractor should check more than the metal box outside. They should look at the duct system, return sizing, supply layout, equipment location, electrical requirements, thermostat compatibility, and airflow needs.
This is especially true with heat pumps and variable-speed systems. These systems can run well in the Bay Area climate, but they need proper sizing, setup, and commissioning. Professional HVAC service should include testing, sizing, and written recommendations before you spend money on a major repair or replacement.
Get the quote and permit plan in writing
Question 7: Will the quote list model numbers, labor, permit handling, warranties, and exclusions?
A complete HVAC quote should be specific enough that you know what you are buying. If the quote just says "install new AC" or "replace furnace," it is too vague.
Ask for the written quote to include:
- Scope of work
- Equipment brand and model numbers
- Efficiency ratings
- Thermostat included or excluded
- Duct changes, sealing, or transitions
- Electrical work included or excluded
- Condensate work
- Refrigerant line work
- Equipment disposal
- Startup and testing
- Permit handling
- Warranty terms
- Labor warranty
- Payment schedule
- Exclusions
Compare scope, not just price. One quote may include permit handling, duct sealing, electrical coordination, startup testing, and warranty labor. Another may leave those items out and look cheaper on day one.
Bay Area permit and inspection requirements can also affect the schedule. Some small repairs may not require a permit, but equipment replacements often do. A good contractor should explain who pulls the permit, what inspection is expected, and what happens if the inspector asks for a correction.
Be careful with large deposits before you have a clear written scope. You should know what system is being installed, what work is included, and what could change the price.
Ask for local proof and accountability
Question 8: Can you explain who is responsible after the job is sold?
Ask for local proof, especially for larger jobs. A contractor doing heat pump replacements in Pleasanton, ductwork in Dublin, furnace swaps in Livermore, or AC service in San Ramon should be able to talk about similar work nearby.
You do not need a staged sales story. You need basic accountability. Ask:
- Who manages the job?
- Who will be on site?
- Who pulls permits?
- Who schedules inspection?
- Who handles callbacks?
- What happens if the system fails inspection?
- What happens if the same problem returns after repair?
- How are warranty claims handled?
A contractor should answer these questions before asking for a deposit. If the answers are rushed, vague, or annoyed, that tells you something.
For repairs, ask how long the recommended part is expected to last and whether other parts are likely to fail soon. For replacements, ask what can wait and what cannot. Sometimes duct upgrades are needed for performance. Sometimes they are optional. You want that explained clearly before work starts.
The right HVAC contractor will not be bothered by these 8 questions. Licensed, insured, trained contractors answer them every day because the details protect both sides.
Talk to an Onzone tech
If you want a licensed Bay Area HVAC contractor to inspect the system, explain the quote, or answer these questions directly, call Onzone Heating & Cooling at (650) 698-7979.
We will tell you what we found, what it costs, and what can wait. If you are ready to book a visit, use this link to schedule HVAC service.
