Free in-home measure and quote - PGT, CGI and CWS impact lines compared on your actual openings, style by style
Fast, Reliable Window Replacement Across Larkspur
Replacing windows in Larkspur means solving two problems at once: fog that never quite leaves the canyon and a fire code that doesn’t care what the fog does. We’ve worked both sides of that equation on Magnolia Avenue Victorians and post-war hillside sliders above Baltimore Canyon. Most full-frame replacements in Larkspur run $1,400 to $3,100 per window installed, and insert replacements typically land between $850 and $1,800 per opening, depending on glazing requirements and frame condition. Owen Satterfield built Window Replacement at Westlight to handle the coastal-spec work the cheap quotes skip. Call (903) 354-7134 and we’ll walk you through what your specific house actually needs.

Why Westlight Windows & Doors Is Larkspur’s Preferred Window Replacement Company
We’re an independently owned and operated Kingswell location, and we’ve been installing windows since 2009. What that means on a Larkspur job is a written price before any work starts, a real arrival window, and a written guarantee on the completed work. If something fails within the guarantee period, we come back and fix it at no charge. That’s the 365-Day Done Right Promise, and it’s in writing on every job.
Larkspur homeowners call us after another contractor no-showed or quoted inland-spec hardware on a canyon-side house. The difference shows up in the details: background-checked, uniformed technicians who tell you exactly what they’re doing, and a real person who answers the phone 24/7, not a voicemail tree. Our Larkspur customers regularly mention that the job site was cleaner when we left than when we arrived. That’s the Kingswell Way: say the price before the work, show up in the window we gave, leave the place cleaner than we found it, put the guarantee in writing, and come back if it fails.
Window Sash Replacement in Larkspur
Window Sash Replacement in Larkspur means rebuilding the moving panel that holds the glass, not swapping the whole frame. In the canyon neighborhoods, original fir and redwood sash from the 1890s to 1920s absorb the year-round humidity that funnels through the Corte Madera Creek valley. The wood swells, seizes in the jamb, and eventually rots at the sill where fog water collects. You’ll see it on Magnolia Avenue Victorians and Craftsman bungalows: sashes that won’t lift, visible rot at the bottom rail, and weight pockets soft enough to push a probe through.
Canyon-Spec Sash Rebuilds
When we rebuild a sash for a hillside home in the Very High Fire Hazard Severity Zone, the glazing spec changes. California Building Code Chapter 7A requires multi-pane glazing with at least one tempered lite on exterior openings. A standard annealed single-pane sash won’t pass permit on those parcels. Our sash rebuilds start around $700 to $1,400 per window depending on sash size and condition, including marine-grade exterior trim and stainless hardware. It costs more than a paint-and-pray patch, but the alternative is redoing the work in three years when the fog wins again.
Rot Repair Before Re-Sash
If the jamb or sill is soft, the sash isn’t the whole story. We cut back rotted wood, treat the remaining frame, and rebuild the opening before the new sash goes in. Skipping that step is how a “replacement” goes drafty within two seasons. On Larkspur’s older homes this adds $200 to $500 per opening, and it’s the only way the new sash actually seals.
Window Glass Repair in Larkspur
Window Glass Repair in Larkspur covers cracked or fogged panes, failed seals, and single-pane originals that need to become tempered, multi-pane units. The fog that keeps Larkspur green also finds its way into failed insulated glass units. Once the seal goes, condensation builds between the panes and the window’s thermal performance drops to nearly nothing. On canyon-side parcels, that also means the unit is no longer meeting the Chapter 7A fire-zone glazing requirement.
IGU Replacement vs. Full Sash Swap
When the frame is sound, we can replace just the insulated glass unit. In Larkspur, that typically runs $350 to $800 per window for standard sizes, more for tempered or fire-rated glass. If the sash itself is rotted or the frame has moved, a full sash replacement is the better spend. We’ll tell you which one your window actually needs rather than defaulting to the bigger ticket. That’s the whole point of a written, honest price before the work starts.
Fogged Glass and Seal Failure
Fogged glass isn’t a cleaning problem; it’s a seal failure. Once moisture is inside the unit, no amount of wiping fixes it. In Larkspur’s marine air, we recommend low-e insulated glass with a warm-edge spacer that resists the thermal cycling that drives seal failure. A low-e coating is a thin layer that reflects heat back into the room in winter and back out in summer. It’s the single best upgrade for a fogged unit that’s coming out anyway.

Trusted Brands We Service in Larkspur
We carry eight manufacturer lines, which means we can match the product to the job instead of forcing the job to fit one brand. For Larkspur canyon homes, PGT and CGI impact-rated windows get specified frequently because they carry the multi-pane tempered assemblies Chapter 7A demands. ViewLux and CWS work well on the flatland Victorians and Craftsman homes where style matters as much as the fire rating. Quick turnaround happens because we stock local parts for Larkspur jobs, not because we’re guessing from a catalog.
Common Window Replacement Problems We See in Larkspur Homes
- Seized aluminum sliders on the hillside builds. The post-war homes above Baltimore Canyon were often framed with single-pane aluminum sliders. Decades of canyon fog corrode the tracks and the sashes bind, then summer north winds off the bay tear past the hardened weatherstripping. We replace these with marine-grade vinyl or thermally broken aluminum frames rated for the exposure.
- Swollen, rotted fir sashes on Magnolia Avenue. The original single-pane wood windows in the late-Victorian and Craftsman homes absorb the valley’s humidity year-round. Sills rot, sashes seize, and weight pockets go soft. A sash replacement that doesn’t address the moisture path is temporary by definition.
- Permit holds on canyon-side parcels. Homeowners on streets backing up to Baltimore Canyon Open Space Preserve get flagged when the glazing doesn’t include a tempered lite. The window was fine except for the part where it won’t pass inspection. We quote the Chapter 7A-compliant spec from the start.
- Failed seals on original and early-replacement double-panes. Fog between the panes, hazy glass, drafts that weren’t there five years ago. Larkspur’s marine air accelerates seal failure once the edge seal goes. The fix is a new low-e IGU, not a silicone bead over the crack.
Pricing for Window Replacement in Larkspur, CA
Here’s the honest range. Full-frame replacement in Larkspur runs $1,400 to $3,100 per window installed, including disposal of the old unit and new interior and exterior trim. Insert replacement, where a new window fits inside the existing sound frame, runs $850 to $1,800 per opening. Window glass repair, meaning a new IGU in an existing sash, lands between $350 and $800 per unit. Sash rebuilds run $700 to $1,400 per window. The coastal-spec premium over an inland quote is real: tempered fire-rated glazing, stainless hardware, and marine-grade trim add 15 to 30 percent to the material cost, and skipping them guarantees a re-buy within a decade. Every Westlight quote is a written, no-surprise price before any work starts. Call (903) 354-7134 for your free estimate.
We Also Serve Cities Near Larkspur
Westlight schedules crews into Larkspur from our San Francisco Bay Area office, and we regularly take on work in Kentfield, Corte Madera, San Rafael, and Mill Valley. The canyon spec changes block by block, but the standard doesn’t: written price, real arrival window, clean job site, written guarantee. If you’re up the hill or down in the flats, the window problems follow the fog line more than the city boundary.
Serving Larkspur, CA - Our Local Coverage Area
We’re based in the Larkspur area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About Window Replacement in Larkspur
Yes, if your parcel falls inside the Very High Fire Hazard Severity Zone boundary, California Building Code Chapter 7A requires exterior glazing to be multi-pane with at least one tempered lite. The Marin County Building Department enforces that on hillside parcels above the canyon, even if the home itself predates the code. Confirm your lot’s zoning before you sign a quote that skips the fire-rated spec; a permit hold wipes out any savings from the cheaper glazing. Call (903) 354-7134 and we’ll check the map for your address.
The coastal-spec window runs 15 to 30 percent more than an inland-spec quote, and the difference lands in three places: tempered fire-rated glazing, stainless or hot-dip hardware instead of painted steel, and marine-grade exterior trim that won’t swell and rot in the fog. A cheaper quote that misses these items gets flagged at permit or fails within a few seasons, and you pay for the correct work anyway. We quote the coastal spec from the first visit so the number you see is the number you pay.
It’s the fog. Larkspur isn’t right on the ocean; the moisture that rots your fir sashes is the marine layer that funnels up the Corte Madera Creek valley and sits in the canyon neighborhoods. The redwood canopy holds that humidity against the wood, which swells the sashes, seizes the hardware, and rots the sills and jambs. We see this constantly on Magnolia Avenue originals from the 1910s and 1920s. The fix is a sash rebuild with stainless hardware and a marine-grade frame treatment, not a quick sash sanding.
Low-e is an energy upgrade; impact-rated is a structural one. For most Larkspur homes outside the fire zone, a low-e insulated glass unit with a warm-edge spacer is the right specification. If your house sits in the Very High FHSZ above Baltimore Canyon, the fire code requires multi-pane tempered glazing, and PGT or CGI impact-rated units are the cleanest way to satisfy that requirement while getting the energy performance. We’ll spec the right glass based on your parcel, not on what’s easiest to stock.
We stock parts and glass for PGT, CGI, CWS, ES Windows, ECO Window Systems, Mr-Glass, Therma-Tru, and ViewLux. That’s eight manufacturer lines, which means a Larkspur canyon job doesn’t stall for three weeks while we order a sash lock from a distributor. When your double-hung needs a new balance or a tempered IGU for the Chapter 7A spec, we pull it from inventory and schedule the install. Call (903) 354-7134 for a written quote on anything from a single fogged pane to a full canyon-side replacement.
West light is the late-afternoon sun that pours through a good window: bright, warm, and worth doing right. If your Larkspur windows are fighting the fog or failing the fire code, call us at (903) 354-7134. We’ll give you a written price before any work starts, show up when we said we would, and put the guarantee in writing. The estimate is free.
Written by Owen Satterfield, Owner at Westlight Windows & Doors, serving Larkspur since 2009.










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