How Much Does Blown-In Insulation Cost in San Francisco?
Blown-in insulation in San Francisco typically costs between $1,900 and $5,800 for a standard attic of 1,000 to 1,500 square feet. Most homeowners in neighborhoods like the Sunset, Richmond, and Noe Valley pay around $3,400 for a complete attic job using fiberglass or cellulose at an R-38 to R-49 depth. The final number depends on your attic’s current R-value, access, and whether air sealing is included.
Blown-In Insulation Cost Breakdown (2026)
The table below reflects what we charge and what we see across the San Francisco market as of 2026. These are real ranges, not national averages – local labor rates, permit requirements, and the age of San Francisco’s housing stock all move the needle.
| Line Item | Cost Range | Notes |
|---|---|---|
| Fiberglass blown-in (attic, R-38) | $1.50 – $2.80 per sq ft | Most common choice; works well in fog-belt microclimates |
| Cellulose blown-in (attic, R-38) | $1.60 – $3.00 per sq ft | Denser; better air-blocking in drafty 1920s-1940s homes |
| Air sealing (can lights, top plates, penetrations) | $400 – $900 | Strongly recommended before blowing insulation; we do this on most jobs |
| Attic prep / removal of old or wet insulation | $800 – $2,200 | Common in older San Francisco homes with original rock wool or vermiculite |
| Rodent droppings cleanup / sanitization | $300 – $700 | We see this often in Richmond and Sunset attics |
| Insulation removal (full tear-out) | $1.50 – $3.50 per sq ft | Required if old insulation is wet, moldy, or compressed below R-19 |
| Dense-pack blown-in (walls, closed cavities) | $2.50 – $4.50 per sq ft of wall | For uninsulated wall cavities in pre-1940 homes |
What moves the price up or down in San Francisco specifically? Three things stand out. First, access: many of the city’s older homes have tight attic hatches, some as small as 18 by 24 inches in the Marina and Inner Richmond, which slows the crew down. Second, existing insulation condition: if the previous owner let a roof leak go, the old material has to come out before anything goes in. Third, R-value target: San Francisco sits in climate zone 3C, which technically requires R-30 to R-38 at the attic floor, but because of the city’s damp, fog-driven winters we commonly recommend R-49, especially for flat-roof homes in the Outer Sunset where moisture settles on interior ceilings.
Bryce Holloway, who leads blown-in insulation in San Francisco for Alden, puts it plainly: “The cheapest bid usually skips air sealing, and the homeowner pays for that in the first fog season.” Every Alden job includes a written price before work begins, and that number is the number on the invoice.
What Affects Blown-In Insulation Pricing in San Francisco
Five factors do most of the work on your final price. Understanding them means you can compare bids fairly.
- Attic square footage and depth. A 1,200 sq ft attic in a Noe Valley single-family home costs more to insulate than an 800 sq ft attic in a Bernal Heights bungalow. Depth matters more than area: going from R-19 to R-49 nearly doubles the material cost.
- Current R-value and insulation condition. Homes built before 1978 in the Richmond and Sunset often have original R-11 batts or loose rock wool that has settled to nothing. If material is wet, moldy, or full of rodent droppings, removal and sanitization add a line item that national pricing guides ignore.
- Air sealing scope. Older San Francisco homes leak air through can light housings, top plates, plumbing stacks, and the chimney chase. Sealing these before blowing insulation is the single highest-return step and typically runs $400 to $900 on its own.
- Attic access. If your access hatch is in a closet and measures 20 by 30 inches, a tech works in a confined space and production slows. Some flat-roof Victorians have no attic at all – just a shallow cavity between ceiling and roof deck – and require dense-pack from outside, which changes the method and the cost.
- Material choice. Fiberglass is typically the lower-cost option and handles the city’s damp air well. Cellulose costs slightly more per square foot but blocks airflow better in drafty pre-war framing. Rockwool runs at the top of the range and adds real fire resistance, which some homeowners in the hills above Glen Park request given the wildfire-season exposure.
One more thing worth understanding: San Francisco does not require a permit for adding attic insulation in most single-family homes, but if your job includes removal of vermiculite or other suspect material, testing and abatement rules come into play. We flag this early, before any price is written.
What You Get With Alden Insulation San Francisco
Alden Attic Insulation is the insulation specialist of the Garrison Partners family, which has been operating since 2002. Each location is independently owned and operated, but every crew works under The Garrison Standard: written prices, written guarantees, and a background-checked technician in uniform who arrives inside the scheduled window.
Here’s what that means in practical terms on a San Francisco job:
- Written price before work starts. The number you approve is the number on the invoice. No door revisions, no surprise line items.
- 365-Day Done Right Promise. Every job carries a written guarantee valid for one full year. If the work fails within that window – say a settled spot drops below R-value, or air sealing pulls away – we come back at no charge. That includes a free second visit if the repair fails.
- Background-checked, uniformed technicians. You know exactly who is walking into your home, and they arrive inside the window we gave you, not a vague half-day range.
- Live answer, 24/7. When you call (559) 245-9792, a real person picks up. Not a voicemail, not a web form, a human being.
- Brand-name materials you can research yourself. We install products from Owens Corning, Johns Manville, Knauf, Rockwool, CertainTeed, Icynene, Demilec, and GreenFiber. Look them up before committing – we want you to know exactly what goes into your attic.
The Garrison Code governs how we run every appointment: show up, be honest about what the job needs, write the price down, and stand behind it. That is not marketing language. It is the operating rule at every Garrison Partners location, including our home base.
Blown-In Insulation in San Francisco: What Actually Works Here
San Francisco has a specific climate, and generic insulation advice misses it. The city runs cool and foggy year-round, with average indoor-outdoor temperature differences smaller than most of California but humidity levels consistently higher. That changes what matters.
In the Outer Richmond and Outer Sunset, fog creeps into attics through gable vents and soffit gaps. Fiberglass blown-in at R-38 handles this fine as long as air sealing is done first. In the Mission and Potrero Hill, where summers are warmer and attics cook under a hot roof deck, cellulose’s higher density does a better job slowing heat transfer through the ceiling. For hillside homes in Twin Peaks and Diamond Heights, wind exposure pulls conditioned air out of the building shell, and air sealing matters more than the insulation itself.
R-value is the trade’s measure of thermal resistance – higher numbers mean more resistance to heat flow. San Francisco code (California Title 24) requires R-30 minimum at the attic floor for new work, but we usually recommend R-38 to R-49 because the city’s damp air makes moisture management as important as the R-number. Wet fiberglass loses its loft and its performance. An R-49 depth of 14 to 16 inches gives you margin against settling and moisture compression.
Is It Cheaper to Repair or Replace Blown-In Insulation?
Most of the time, topping off thin blown-in insulation costs less than a full removal and replacement. If your attic has dry, intact material at R-19 and you want to reach R-38 or R-49, the top-off route typically runs $1,200 to $2,500 for a standard San Francisco attic. Full removal and replacement runs $2,800 to $5,800 depending on square footage and what has to come out.
The deciding factor is condition. If the existing insulation is wet, moldy, matted down by rodents, or contaminated, blowing new material on top seals in the problem. In that case, removal is the right call and the honest one. We tell homeowners this before writing a price either way. Call (559) 245-9792 and we’ll give you a straight answer about your attic.
How to Save on Blown-In Insulation in San Francisco
You don’t need to chase the lowest bid to get a fair price. You need to avoid paying for work that gets redone, and a few practical moves help.
- Get your attic inspected before you get quotes. Knowing your current R-value, moisture condition, and air-sealing needs means every bid you collect is for the same job – not three different jobs.
- Bundle air sealing with insulation. Doing both in one visit saves a mobilization fee and gets the air-leakage work done while the attic is prepped anyway.
- Time the work outside peak heating season. San Francisco’s mild climate means insulation crews stay busy in December and January. Scheduling for October or March often means faster availability, and while our pricing is stable, a flexible schedule gets you on the calendar sooner.
- Check for existing utility rebates. BayREN and PG&E occasionally offer rebates for attic insulation and air sealing in San Francisco, and while they change year to year, they are worth a quick search before you commit.
- Get a written quote from a contractor that does not revise at the door. A low verbal quote that moves when the crew arrives is the most expensive kind there is. Alden’s price is written, and it is the price.
For a free, no-pressure estimate on Blown In Insulation services in San Francisco, call (559) 245-9792. We’ll answer live and schedule a visit that fits your calendar.
FAQs – Blown-In Insulation Cost in San Francisco
How much does blown-in insulation cost per square foot in San Francisco?
Plan on $1.50 to $3.00 per square foot for attic blown-in insulation at R-38, materials and labor included. Dense-pack wall work runs higher, from $2.50 to $4.50 per square foot. Call (559) 245-9792 for an exact number on your attic – estimates are free.
Can you fix low attic insulation in one day?
Yes. A standard attic top-off or full blow-in on a 1,000 to 1,500 square foot San Francisco home is a one-day job. If removal or sanitization is required, plan for two days. We’ll tell you before scheduling.
How much does it cost to remove old insulation in San Francisco?
Removal alone typically runs $1.50 to $3.50 per square foot, so a 1,200 square foot attic lands between $1,800 and $4,200. The range is wide because rodent contamination, moisture damage, and access can all add labor. Call (559) 245-9792 for a written quote.
Is blown-in insulation worth it in San Francisco’s mild climate?
Yes, but for a specific reason: the city’s fog-born moisture. Properly air-sealed and blown-in insulation at R-38 or R-49 stops the warm-wet-air cycle that causes ceiling staining, mold at the attic sheathing, and drafty rooms in older homes. The comfort difference in a 1920s Richmond District house is immediate, and the moisture protection is the real long-term payoff.
What R-value does my San Francisco attic need?
California Title 24 requires R-30 minimum at the attic floor for new work. We recommend R-38 to R-49 in San Francisco because the damp, foggy air compresses insulation over time and a deeper install holds its performance longer. Call (559) 245-9792 and we’ll assess what your attic needs specifically.
Do you offer free estimates for insulation in San Francisco?
Yes. Every estimate is free, and the price we show you is written down before any work begins. Call (559) 245-9792 any time – a live person answers, day or night.
Written by Bryce Holloway, Owner at Alden Insulation San Francisco, serving San Francisco since 2002.
Pricing reflects the San Francisco market as of 2026. Alden Insulation San Francisco offers free estimates – call (559) 245-9792.
What Our Customers Say
"Tidy crew. Vacuumed the hall and covered the hatch."
- Bea J."Spray foam in the rim joist. Floors above are warmer."
- Iris L."Blown-in insulation in the attic by a veteran crew. They air sealed the top plates first, installed baffles, and marked the depth with rulers. Bills dropped right away."
- Roy H.