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Sanitizing & deodorizingWhole-system duct and dryer vent check with before-and-after photos - you see exactly what came out of your vents
That "$99 whole-house special" is a bait ad - the real number appears once they are in your hallway, or the "clean" is a shop-vac at the register. We photograph the inside of your ducts before and after instead.
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AfterHow Much Does Duct Repair & Sealing Cost in San Francisco?
Duct repair and sealing in San Francisco typically costs between $350 and $1,400 for most jobs, with a citywide average around $750. Small, accessible leaks run $200 to $450, while extensive repairs across multiple runs or replacement of damaged sections can reach $2,500 or more. Duct Repair & Sealing in San Francisco pricing depends on access, duct material, and how much of the system needs attention.
Key Takeaways:
- Average duct repair and sealing job in San Francisco: $350 – $1,400
- Simple accessible leak sealing: $200 – $450
- Full-system sealing with multiple repairs: $1,500 – $2,800
- Most jobs take 3 to 6 hours on-site
- Written price before any work starts, every time, here at home base for Linden Air Duct San Francisco
Duct Repair & Sealing Cost Breakdown (2026)
Here’s what we’re seeing across San Francisco neighborhoods right now, from the Sunset to Bernal Heights. These are real ranges from jobs we’ve priced in this market, not national averages squeezed into a San Francisco zip code.
| Job Type | Typical Cost Range | What’s Included |
|---|---|---|
| Single accessible leak seal | $200 – $450 | One visible joint or small tear, mastic or foil tape, under 60 minutes |
| Multiple leaks / moderate sealing | $450 – $900 | 3 – 6 joints or small holes, access panels as needed, 2 – 3 hours |
| Duct section replacement (5 – 10 ft) | $600 – $1,300 | Remove damaged flex duct, install new, seal both ends, check airflow |
| Full-system sealing | $1,500 – $2,800 | All accessible joints and seams sealed, pressure test, before/after airflow check |
| Emergency repair (same-day, off-hours) | $500 – $1,200 | Priority scheduling, typically after-hours or weekend arrival |
Several things push a job toward the higher end. Crawlspace access in older Richmond and Sunset District homes, where clearance is under 18 inches, adds labor time. Homes built before 1950 often have asbestos-wrapped ducts in San Francisco, which requires assessment before any repair work can begin. And if your ducts run through finished walls or ceilings in a condo in SoMa or Mission Bay, access alone can add $200 to $400 to the final number.
Not every job needs full replacement. In many San Francisco homes, we find that 70 to 80 percent of duct leakage comes from a handful of failed joints. Sealing those specific points with professional-grade mastic, applied to a clean, dry surface, often drops leakage dramatically without touching the rest of the system.
What Affects Duct Repair & Sealing Pricing in San Francisco
- Access to the ducts. San Francisco basements, crawlspaces, and attics are notoriously tight. A duct run in a stand-up attic takes half the labor of the same run in a 16-inch crawlspace, and labor is the biggest single line item in any repair quote.
- Duct material. Flexible duct is faster and cheaper to replace, typically $12 to $18 per linear foot installed. Rigid galvanized duct runs $25 to $40 per linear foot, and San Francisco’s older Victorians and Edwardians often have rigid runs that need custom fabrication.
- Number of leaks and their location. One leak at an accessible boot fitting is a 45-minute fix. Ten leaks spread across a three-story Noe Valley home is a full day. The math is straightforward: more leaks, more hours, higher invoice.
- Age and condition of the system. Ducts in homes built before 1980 frequently have failing tape, rusting collars, or compressed flex. If the duct itself is degraded, sealing is a bandage, not a fix. Repair costs rise when sections need replacement rather than sealing.
- Testing and verification. We include a before-and-after airflow check on every repair. If you want a full duct leakage test with a calibrated fan and pressure gauges, that adds $150 to $300. It’s the only way to quantify improvement in CFM terms, and worth it for whole-system jobs.
- Permit requirements. Most duct repair and sealing in San Francisco doesn’t require a permit, but if the work touches a mechanical system in a multi-unit building, SFDBI may require a mechanical permit. That’s $180 to $400 in fees, plus inspection time. We’ll tell you upfront if your job needs one.
How to Save on Duct Repair & Sealing
The biggest money-saver in this trade is catching leaks early. A small accessible leak costs a few hundred dollars to fix. The same leak left for two years pulls dust, moisture, and unconditioned air through the system, often causing secondary damage that triples the repair cost.
Here are practical ways to keep your bill down:
- Know where your ducts run before you call. Mark the access points. Show us the attic hatch, the crawlspace entry. Each minute we spend hunting for access is billable time.
- Clear the path. If we need to reach a duct behind stored boxes or furniture, that’s labor you’re paying for. Clear what you can.
- Bundle repairs. If you have two or three known problem areas, do them in one visit. Mobilization is a real cost. One trip for three fixes is always cheaper than three trips for one fix each.
- Ask for a written price first. Never accept a verbal estimate. A written price before work begins tells you exactly what the job costs, with no surprise line items at the end. Linden Air Duct San Francisco does this on every job, with no exceptions.
- Get a free estimate and an exact scope. Call (951) 527-6259 before you commit to anything. We’ll walk the system with you, explain what’s actually leaking, and put a number in writing. Estimates are free.
Is It Cheaper to Repair or Replace Ductwork?
For most San Francisco homes, repair and sealing is significantly cheaper than replacement. A full duct replacement in a typical 1,800-square-foot home runs $4,500 to $9,000, while comprehensive repair and sealing lands between $350 and $2,800. If the ductwork is under 25 years old and structurally sound, sealing is almost always the right financial call.
Replacement makes sense when we’re seeing corroded metal, collapsed flex, mold growth inside the duct liner, or asbestos-wrapped ducts that can’t be safely repaired. In those cases, continued patching is throwing money at a system that needs to go. We’ll tell you plainly which category you’re in, and we’ll never recommend replacement when sealing would do the job.
How Long Does Duct Repair & Sealing Take?
A single accessible leak is typically sealed in under an hour on-site. Multi-point sealing jobs run 3 to 6 hours. Full-system sealing with testing takes 6 to 8 hours, occasionally split across two days for large homes. Emergency same-day repairs, where we fit you into the schedule, still follow the same written-price process: you get the number before we start, every time.
Can You Do Duct Sealing Yourself?
You can seal an exposed, accessible duct joint with foil tape or mastic from a hardware store. That’s honest. But here’s what we see in San Francisco homes after DIY attempts: gaps sealed with the wrong product, ducts partially crushed from insufficient support, and leaks that were never actually reached because most of the system hides inside walls, floors, and crawlspaces.
If you’re sealing a visible seam in an unfinished basement, go ahead. If the leak is in a crawlspace, inside a chase, or you’re not sure where the air is actually escaping, call a professional. Duct work also involves sharp sheet metal edges and, in some older San Francisco homes, potential asbestos wrap. Cutting into an asbestos-wrapped duct without testing is dangerous. We test before we touch anything that predates 1980.
FAQs – Duct Repair & Sealing Cost
How much does it cost to seal ductwork in San Francisco?
Sealing existing ductwork in San Francisco costs $350 to $2,800 depending on scope. Simple accessible leaks run $200 to $450, while whole-system sealing with pressure testing lands between $1,500 and $2,800. Call (951) 527-6259 for an exact written quote. Estimates are free.
Can you fix a leaking duct the same day?
Yes, in most cases we can arrive same-day or next-day for urgent duct repairs in San Francisco. Emergency repairs run $500 to $1,200 depending on scope and timing. We answer the phone with a live person 24/7, so you’ll speak to a human immediately, not a voicemail loop.
What does duct mastic sealing cost per vent or joint?
Sealing a single accessible duct joint or vent boot typically costs $40 to $90 in San Francisco when done as part of a larger job. Standalone single-joint visits run $200 to $300 due to the minimum service call. Most homes have 10 to 20 joints, which is why whole-system pricing starts around $1,500.
Is duct sealing worth the cost?
For most San Francisco homes, yes. The U.S. Department of Energy estimates that typical duct systems lose 20 to 30 percent of conditioned air through leaks. Sealing those leaks means your furnace and AC stop heating and cooling the crawlspace, which typically reduces energy bills by 10 to 20 percent annually. On a $2,500 annual heating and cooling bill, that’s $250 to $500 back every year.
What’s included in Linden’s duct repair price?
Every Linden Air Duct San Francisco repair price includes a written quote before work starts, the repair itself using professional-grade materials, a before-and-after airflow check, and a written 365-Day Done Right Promise. If the repair fails within 365 days, we come back at no charge. Your technician’s name and photo arrive before the visit, and they’ll show a photo ID badge at your door. No exceptions.
Does duct sealing require a permit in San Francisco?
Most single-family duct sealing does not require a permit in San Francisco. Multi-unit buildings or jobs that modify mechanical systems may need an SFDBI mechanical permit, which adds $180 to $400 in fees. We’ll tell you upfront if your specific job needs one, and we’ll never start work without the right paperwork in place.
Who You’ll See at Your Door in San Francisco
Hiring a duct repair company means inviting someone into your home, often into tight, hidden spaces. We take that seriously. Every Linden technician is background-checked and identity-verified under the Threshold Standard, the verification protocol we’ve operated under since 2004 as part of the Threshold Group family. You receive the technician’s name and photo before the visit. They arrive in a clean, marked uniform. They show a photo ID badge at your door, every single time. Marcus Veale, who leads Linden Air Duct San Francisco, built the local operation around these protocols because he believes you should never wonder who’s in your home.
We run professional-grade equipment from Rotobrush and Nikro, and we work with air-quality products from Honeywell, Aprilaire, Abatement Technologies, and Guardsman where a job calls for them. But the equipment matters less than the person running it. That’s why we screen, verify, and introduce every technician by name before they ever step inside.
Get a Written Price Before You Decide
Duct repair and sealing in San Francisco costs $350 to $1,400 for most jobs. Your specific system may be simpler or more involved. The only way to know is a look at the actual ductwork, and we’re glad to do that without charge or pressure.
Call (951) 527-6259 and you’ll speak with a live person, any hour, any day. We’ll schedule a free estimate, walk the system with you, and put a written price in your hand before any work begins. If the repair doesn’t hold, the 365-Day Done Right Promise means we come back and make it right at no charge. That commitment is in writing on every job, and it’s been our standard since day one.
Written by Marcus Veale, Owner at Linden Air Duct San Francisco, serving San Francisco since 2004.
Pricing reflects the San Francisco market as of 2026. Linden Air Duct San Francisco offers free estimates – call (951) 527-6259.
What Our Customers Say
"Had a dryer vent clog that was making towels take two cycles. Cleared a huge lint wad from the roof end. Dryer is back to one cycle."
- Ben K."Tech arrived with a badge and a printed sheet of what he'd be doing. Ran a camera through the main trunk before and after so I could see the dust difference. Vents smell cleaner already."
- Gina R."He showed me the debris from the blower motor housing, which I'd never have seen otherwise. The furnace runs quieter now."
- Jasmine T.