HVAC Permits, Codes & Inspections in CA: What You Need to Know

HVAC Permits, Codes & Inspections in CA: What You Need to Know

Most San Francisco homeowners only learn the permit rules after something goes wrong. A buyer’s inspector flags an unpermitted furnace during escrow. An insurance adjuster asks for documentation that was never pulled. A failed rough inspection voids a manufacturer warranty. What costs a few hundred dollars and a few weeks of waiting can, if skipped, turn into a retrofit that costs thousands. This guide lays out exactly which HVAC projects in San Francisco require a permit, which California Title 24 and local code requirements apply, and what happens during each inspection. For HVAC Warning Signs: A San Francisco Homeowner’s Reference Guide, see our companion resource. By the end, you’ll know more about the process than many contractors who claim they handle it.

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Quick Answer

In San Francisco, any HVAC work that involves replacing a furnace, air conditioner, or heat pump requires a permit from the Department of Building Inspection (DBI). Minor repairs like swapping a capacitor, contactor, ignitor, or thermostat do not. California’s Title 24 energy code sets minimum efficiency, duct sealing, and airflow standards that affect which equipment qualifies for installation, while San Francisco’s local amendments to the California Mechanical Code add requirements around seismic strapping, ventilation, and condensate discharge that a statewide contractor may not know. Inspections happen in stages: rough, duct, and final. Each stage must pass before the next begins.

Table of Contents

• Which HVAC Projects Need a Permit in San Francisco – and Which Don’t
• How California Title 24 Affects Which Equipment You Can Install
• San Francisco’s Local Amendments to the California Mechanical Code
• The Inspection Sequence: Rough, Duct, and Final – What the DBI Inspector Actually Checks
• How Permit Records Protect You: Insurance, Resale, and the DBI File
• How to Pull Your Own San Francisco Permit History
• What Permits Cost and How Long They Take in San Francisco
• Common Mistakes to Avoid
• When to Call a Professional
• Frequently Asked Questions

Which HVAC Projects Need a Permit in San Francisco – and Which Don’t

San Francisco follows the California Mechanical Code, which requires permits for any installation, alteration, or replacement of a furnace, air conditioner, heat pump, or duct system. But the line between a repair and a replacement is drawn more precisely than most people realize, and contractors get it wrong in both directions.

Here’s the practical breakdown, based on what we’ve seen in San Francisco homes across Noe Valley, the Richmond, the Sunset, and Bayview:

Work that requires a permit in San Francisco:

• Replacing a furnace, air handler, heat pump condenser, or evaporator coil
• Installing new ductwork or replacing more than a short connector run
• Adding a new supply or return register, which means modifying the duct system
• Changing out a gas line connection to a furnace (gas work triggers its own inspection requirements)
• Upgrading an electrical circuit, breaker, or disconnect for AC equipment
• Relocating an indoor unit or outdoor condenser to a new spot on the property
• Converting from a furnace to a heat pump or vice versa

Work that does NOT require a permit in San Francisco:

• Replacing a capacitor, contactor, thermostat, ignitor, flame sensor, or pressure switch
• Charging or topping off refrigerant on an existing system
• Cleaning coils, condensate lines, or blower assemblies
• Replacing an air filter or belt
• Tightening electrical connections inside the unit
• Any AC maintenance in San Francisco that restores existing equipment to working order without changing the system layout

The governing principle is simple: if you’re swapping a component, it’s a repair. If you’re changing the equipment, the duct design, the gas connection, the electrical load, or the installed location, it’s an alteration and the DBI wants to see it. A good contractor will tell you which category your job falls into before work starts, and the written estimate should state explicitly whether a permit is included. If the estimate says “permit extra” or doesn’t mention it at all, ask directly. We put permit status in the written price, every time, no exceptions.

How California Title 24 Affects Which Equipment You Can Install

California’s Title 24 energy code is the reason you can’t just buy any furnace or AC and have it bolted in. Title 24 sets minimum efficiency ratings, and more importantly, it sets duct and airflow requirements that affect the entire installation. A furnace that meets federal efficiency standards can still fail Title 24 compliance in San Francisco if the ducts leak or the airflow doesn’t match the unit. Our Seasonal HVAC Care for San Francisco: Year-Round Homeowner’s Guide covers how to keep your system compliant between inspections.

Here’s what matters in practice:

1. Minimum efficiency, not just the unit’s rating. Title 24 requires a minimum SEER2 rating for air conditioners (currently 14.3 for split systems in most of California, higher in some climate zones) and a minimum AFUE for furnaces. San Francisco sits in climate zone 3, which is milder than inland areas, but the same equipment rules apply statewide.
2. Duct leakage testing. Title 24 requires that new or altered duct systems be tested for leakage. In San Francisco, the standard is that ducts must leak no more than 5% of total airflow. A contractor who doesn’t know this number will seal ducts until they “look fine,” which isn’t the same as passing a duct test. The inspector may ask to see the test results.
3. Refrigerant charge verification. For any new AC or heat pump, Title 24 requires that the refrigerant charge be verified against the manufacturer’s specifications using a superheat or subcooling method. This is not optional paperwork. Failed verification means a failed final inspection.
4. Airflow rate. New systems must have airflow measured and verified against design specifications. An oversized furnace on undersized ducts will fail. This is one of the most common reasons San Francisco installations fail their final inspection: the homeowner’s old ducts were fine for the old 80% furnace, but they can’t move enough air for the new high-efficiency unit.

Brands like Carrier, Trane, and Bryant all manufacture equipment that meets Title 24 minimums, but the equipment is only half the equation. The installation as a whole – ducts, refrigerant, airflow – is what passes or fails. When we price a system replacement in San Francisco, the load calculation and duct assessment happen before we quote the equipment, because we don’t want to sell you a unit that can’t pass inspection.

San Francisco’s Local Amendments to the California Mechanical Code

San Francisco is one of a handful of California cities that amends the state mechanical code with its own local rules. The San Francisco Mechanical Code, adopted and amended by the DBI, includes requirements that a contractor licensed in Sacramento or San Jose may have never encountered. If your contractor only knows the California Mechanical Code, they may not know the San Francisco amendments. That’s a real problem when it’s your furnace at stake.

The local amendments that come up most often in San Francisco HVAC work:

• Seismic strapping and bracing. San Francisco’s code has stricter earthquake-resistant bracing requirements for water heaters and, in some configurations, for furnaces and air handlers in garages or basements. The DBI inspector will check strapping. A contractor who does work in Concord or Walnut Creek may never have seen San Francisco’s specific bracing detail.
• Gas piping and flex connector length limits. San Francisco restricts the length and location of flexible gas connectors on furnaces and water heaters. The state code allows up to 6 feet; San Francisco’s amendments are more restrictive in certain installations, and the inspector will measure.
• Condensate discharge rules. Where condensate lines terminate – into a drain, outside, into a pump – is regulated differently in San Francisco than in many other California cities. Discharging onto a sidewalk or into a neighbor’s property line gets flagged.
• Ventilation requirements for gas appliances. San Francisco requires specific makeup air provisions for gas furnaces in enclosed spaces, especially in older homes with sealed-up garages or closed basements. The required vent size is sometimes larger than what the statewide mechanical code calls for.
• Permit posting and worksite documentation. The DBI expects the permit card visible on site, and inspectors can and do stop work if it isn’t posted.

The takeaway: hire a contractor who pulls permits in San Francisco regularly, not one who “has done HVAC for 20 years” but files most of their permits in other counties. The difference shows up at inspection time. We’ve seen furnace repairs in San Francisco that became furnace replacements because the original unpermitted installation failed on seismic strapping and the homeowner had no recourse against the contractor who’d left town. Permit. Every. Time.

The Inspection Sequence: Rough, Duct, and Final – What the DBI Inspector Actually Checks

San Francisco HVAC permit inspections happen in three stages. Not every project requires all three, but a full furnace or AC replacement with duct work does. Each stage must pass before the next is scheduled, and a failed inspection stops the project and requires a re-inspection fee.

Stage 1: Rough Inspection

The rough inspection happens after the equipment is set and the ducts are connected, but before walls, insulation, or drywall cover anything. The DBI inspector is checking:

• That the furnace, air handler, or coil matches what’s on the permit documents
• Gas line size, connections, sediment trap, and shutoff valve placement
• Electrical connections, disconnect switch, and conduit
• Seismic strapping and bracing, especially in garages and basements
• Clearance to combustibles around the furnace
• Condensate drain slope and termination

A failed rough inspection usually comes down to one of three things: wrong gas line size, missing seismic strapping, or a condensate line that doesn’t slope. All three are preventable with a contractor who knows the San Francisco amendments.

Stage 2: Duct Inspection

Not every jurisdiction does a separate duct inspection, but San Francisco does when ductwork is new or substantially altered. The inspector checks:

• Duct connections are sealed with approved mastic or foil tape (not cloth duct tape)
• No ducts are kinked, crushed, or undersized for the equipment
• Insulation on ducts in unconditioned spaces meets San Francisco’s R-value requirement
• Duct leakage test results, when required under Title 24

A failed duct inspection can void a manufacturer warranty. Carrier, Trane, and American Standard all condition their compressor and heat exchanger warranties on proper installation, and an unpermitted or failed installation gives the manufacturer a reason to deny a claim. We tell San Francisco homeowners this plainly: the permit isn’t bureaucracy, it’s the document that keeps your warranty alive. Our AC Repair Maintenance Checklist for San Francisco Homeowners shows what to verify before each inspection.

Stage 3: Final Inspection

The final inspection happens after everything is complete and the system runs. The inspector verifies:

• The system starts, heats, and cools correctly
• Refrigerant charge is verified (for AC and heat pump installations)
• Airflow is within the manufacturer’s specified range
• All safety devices – limits, pressure switches – function
• The permit card is signed and the inspection is recorded with DBI

Once the final passes, the permit is closed, the inspection is on file with the city, and your manufacturer warranty is clean. It’s the difference between a system with documented history and one with a question mark hanging over it.

How Permit Records Protect You: Insurance, Resale, and the DBI File

A closed permit is a piece of paper, but it’s the piece of paper that stands between you and a fight you don’t want. In our experience in San Francisco, the permit file matters in three specific situations:

1. Insurance claims. If your furnace causes a fire, a gas leak, or water damage, your insurer will ask for the installation and maintenance history. An unpermitted installation is a reason to deny a claim or reduce a payout. Insurers don’t need proof that the unpermitted work caused the damage. They just need the fact that it was unpermitted. A closed DBI permit with passed inspections is your strongest evidence that the work was done to code.

2. Resale and escrow. San Francisco’s real estate market is famously tight, and buyers here are more likely than average to pull a permit history before closing. If the permit history shows a furnace replacement in 2021 with no permit, the buyer’s inspector will flag it. You may be asked to obtain a retroactive permit (which requires opening walls back up for inspection) or credit the buyer for the cost of remediation. The permit costs about $250. The retrofit after the fact can cost $3,000 to $10,000 depending on what’s hidden behind drywall.

3. Contractor disputes. A permit record proves what work was done, when, and by whom. If a repair fails a year later, the permit file establishes the timeline. Under our 365-Day Done Right Promise, if a repair we performed fails within the guarantee period, we return at no charge – and the permit and inspection documentation makes the chain of responsibility easy to follow. That’s how documentation protects you, not just the city.

How to Pull Your Own San Francisco Permit History

You don’t need to be a contractor or a lawyer to see what permits exist for your property. San Francisco’s Department of Building Inspection keeps permit records searchable online, and pulling your own history takes about ten minutes.

Here’s the step-by-step:

1. Go to the San Francisco DBI website and open the “Permit Tracking” or “Permit & Property Information” portal.
2. Search by your street address, not your name. Permit records are filed by property, so the address is the reliable key.
3. Look at the list of permits associated with the address. Each permit will show a type (mechanical, electrical, plumbing), a status (issued, finaled, expired), and dates.
4. For HVAC work, look for “mechanical” permits that correspond to the years you know work was done. A furnace replacement will be a mechanical permit. An AC install may also show an electrical permit.
5. If you see a permit with status “issued” but not “finaled,” that means work was started or a permit was pulled but the final inspection never passed. That’s a red flag if you’re buying the property.

You can also call DBI directly or visit the permit center at 49 South Van Ness Avenue, but for most homeowners the online portal is faster and searchable at any hour. If you’re the seller, do this before you list. If you’re the buyer, do it before you remove contingencies. We tell every AC repair in San Francisco customer the same thing: know what’s on file before you need it in a dispute.

What Permits Cost and How Long They Take in San Francisco

Permit fees in San Francisco are modest compared to the cost of the equipment they cover, but the timeline is where we see homeowners get frustrated. Plan for it.

Typical permit costs for HVAC work in San Francisco:

• Furnace replacement permit: typically $200 to $350, depending on valuation
• AC or heat pump install permit: typically $200 to $400
• Full system replacement (furnace + AC + duct alterations): $400 to $800
• Re-inspection fee after a failed inspection: usually $100 to $200 per visit

The permit fee is based on the declared valuation of the work, not a flat charge, so a high-efficiency system with new ductwork will push toward the top of the range. These are the numbers we see on San Francisco jobs, and they should be listed separately on your written estimate so you know exactly what the city is charging and what the labor costs separately. That’s our practice: written price before any work starts, with the permit line item shown in plain numbers.

Timeline in San Francisco:

• Permit application review for a standard residential mechanical permit: 2 to 5 business days
• Over-the-counter issuance for simple replacements: sometimes same day, depending on DBI staffing
• Scheduling a rough inspection: typically 2 to 10 business days after work is ready for inspection
• Scheduling final inspection: 2 to 5 business days after rough and duct inspections pass

A straightforward furnace swap in San Francisco can be completed, permitted, and finaled in 2 to 3 weeks from the day you accept the estimate. A complex job with duct alterations or electrical upgrades can run 4 to 6 weeks. The timeline is not a reason to skip the permit. It’s a reason to start with a contractor who pulls permits in San Francisco regularly and schedules inspections without the homeowner having to chase anyone.

Common Mistakes to Avoid

• Believing “it’s a repair” when it’s actually an alteration. A contractor who calls a furnace replacement a “repair” to avoid pulling a permit is shifting risk onto you. The city doesn’t care what the invoice says. It cares whether the equipment changed. If the serial number on the permit doesn’t match the serial number on the unit, you have a problem.
• Not checking permit status before buying a home. San Francisco buyers sometimes skip the permit history in a competitive market. Don’t. A $10,000 retroactive remediation wipes out any “savings” from skipping the inspection contingency.
• Using a contractor who only knows the state code. San Francisco’s local amendments on seismic strapping, gas connectors, and condensate lines are specific. A contractor who doesn’t work in San Francisco regularly will learn your local requirements at your re-inspection fee.
• Thinking the permit fee is “extra” and skippable. The permit costs a few hundred dollars. The unpermitted retrofit costs thousands. Short-term savings, long-term liability.
• Not getting the duct leakage test. Title 24 requires it on new or altered ducts. An inspector may not ask for the number on a simple replacement, but if the issue ever comes up in a warranty claim or an insurance claim, the missing test is a hole in your documentation.
• Letting the permit expire. A San Francisco permit expires if work doesn’t start within a set window (often 180 days) or if inspections aren’t scheduled. An expired permit is the same as no permit in the eyes of the DBI – and your buyer’s inspector will see it.
• Assuming the contractor’s word is enough. A good contractor puts the permit number on the written estimate and lets you track it yourself on the DBI portal. If they won’t show you the number, that’s information too.

When to Call a Professional

The permit process is not something to navigate alone, and it’s not something to delegate casually. If you’re replacing a furnace, heat pump, or AC in San Francisco, the contractor you choose is either managing your permit correctly or creating a problem you’ll discover later. Ask for the permit number before work starts. Ask which inspections will happen. Ask if the price includes all permit and inspection fees. If the answers are vague, call someone else.

Brandt HVAC Co San Francisco offers free estimates in San Francisco – call (559) 245-8807. We’ll give you a written price that includes the permit, and we’ll tell you exactly which inspections apply to your job before anything is installed. No surprises at inspection time, no retroactive permits, no warranty fights.

Frequently Asked Questions

The Bottom Line

San Francisco’s HVAC permit process exists at the intersection of three rule sets: California’s Title 24 energy code, the California Mechanical Code, and San Francisco’s local amendments. A contractor who knows all three will get your furnace or AC installed, inspected, and finaled without drama. One who doesn’t will transfer the risk to you. Get the written price. Verify the permit number. Track the inspections. And if you ever have a question about what’s actually required in San Francisco, call us at (559) 245-8807 – we’ll tell you straight, whether or not we do the work.

Written by Devin Marlowe, Owner at Brandt HVAC Co San Francisco, serving San Francisco since 2003.