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 Mill Valley
Window replacement in Mill Valley runs $900-$2,800 per opening for most homes, depending on whether you need a full frame replacement or an insert, and on the fire-rated glazing Marin County requires. Full frame work on an average 12-window Mill Valley house lands between $14,000 and $34,000. We’re TruePane Windows & Doors, and we’ve been setting windows in this canyon town long enough to know what the redwood drip does to a fir jamb and what the WUI inspector will look for before he signs off. Call (888) 635-0804 for a free estimate, and we’ll walk your windows with you before we quote anything.
Why TruePane Windows & Doors Is Mill Valley’s Preferred Window Replacement Company
Dale Kessler founded TruePane in 2008 after years of watching out-of-true installs void warranties and leave homeowners holding fogged glass. We’ve spent the years since doing things the way a glazier should: measuring every opening twice, quoting manufacturer lines side by side on paper, and registering both warranty layers in writing before the truck leaves the driveway. Mill Valley homeowners call us because the Done Right Promise means what it says. If the work isn’t right, we make it right. No paperwork fight, no “that’s not covered.”
Our technicians are background-checked, uniformed, and trained to work the way they’d work in their own mother’s house. We sponsor county fairs and church roof funds around Marin because we plan to be here in thirty years. A live person answers our phone 24 hours a day, seven days a week. That matters in Mill Valley, where a failed window on a hillside contemporary can let the marine layer into the wall cavity overnight.
We know the Cascade Canyon fog pattern, the Blithedale drainage, and the Old Mill bungalows with original fir sashes that have been holding on since the Coolidge administration. We don’t send a different crew every time. We send people who know the ground.
Our Window Replacement Services in Mill Valley
Full Frame Replacement
Full frame replacement in Mill Valley means pulling the entire existing window down to the rough opening, repairing or rebuilding the jamb, flashing the new unit correctly, and setting a window that will hold its line for decades. On older Mill Valley stock, especially the early-1900s Craftsman bungalows around the Old Mill area and downtown flatlands, the original fir frames are often compromised by a century of redwood drip and marine-layer damp. We replace the frame, flashing, and trim, not just the sash. A full frame replacement on a standard double-hung in Mill Valley typically runs $1,200-$2,800, including the fire-rated dual-pane tempered glass Marin County requires.

Insert Window Replacement
Insert replacement, sometimes called retrofit, fits a new window into the existing frame when that frame is still square and sound. In Mill Valley, we see fewer truly sound frames than homeowners expect. The same canyon moisture that keeps the redwoods green is rough on wood frames. Before we quote an insert, we probe the sills and jambs for rot with a screwdriver and a moisture meter. If the frame won’t hold another decade, we tell you straight and quote the full frame instead. An insert replacement in Mill Valley typically runs $900-$1,700 per opening.

Storm Window Replacement
Storm windows aren’t just for coastal weather. Mill Valley’s canyon thermal cycling is hard on glazing seals. A storm window adds an air pocket that buffers the temperature swing between morning fog and afternoon heat that cracks older sealants. We install exterior storm windows on historic bungalows where full frame replacement would strip the home’s character, and interior storm panels on newer homes where the homeowner wants better sound and thermal isolation without disturbing the original window. Storm window replacement in Mill Valley typically runs $450-$1,100 per unit. For historic properties under Mill Valley’s preservation review, we coordinate with the design review board before ordering.

Energy-Efficient Upgrade
Mill Valley homes spend more on heat than people expect. The fog that parks in the canyon until late morning keeps interiors cool and damp, and when the afternoon heat pushes toward 90°F up in the Sycamore and Tamalpais foothills, the thermal swing drives up cooling costs. An energy-efficient upgrade replaces single-pane sash with dual-pane tempered low-E glass that cuts that swing. We carry lines from PGT, CGI, and ES Windows, all of which offer low-E options that qualify for Marin County’s efficiency incentives. An energy-efficient upgrade on a Mill Valley home typically adds $200-$500 per opening over a code-minimum unit, paid back in comfort long before the warranty runs out.

What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Mill Valley
TruePane is an authorized installer for more than a dozen manufacturer lines, and we service all of them in Mill Valley. We quote PGT, CGI, ES Windows, Andersen, Pella, Marvin, and others side by side on paper so you can see exactly what each dollar buys. We stock common replacement parts locally for Mill Valley jobs-standard IGUs, balance springs, weather stripping, threshold caps-so we’re not waiting on a regional warehouse when a window fails mid-season. If you’re replacing a full window set in the hills above Cascade Canyon, we can bring brand samples to your living room and talk through fire-rating, U-value, and condensation resistance before you commit.
Common Window Replacement Problems We See in Mill Valley Homes
Before you spend money on replacement windows, it helps to know what the next contractor will actually find. These are the problems we see most often in Mill Valley:
- WUI fire-code compliance failures. Mill Valley sits entirely within California’s Very High Fire Hazard Severity Zone. Marin County’s WUI ordinances require dual-pane tempered glass, tight-seal frames with no combustible gaps, and ember-resistant construction on any window or door replacement. Out-of-town contractors who quote standard inserts are quoting a failed inspection. We pull the Mill Valley permit on every job and build to the local ordinance, not the state minimum.
- Redwood drip rot in original fir and redwood frames. The dense canopy above homes in Cascade Canyon and the downtown groves drips moisture onto window sills and jambs for hours after a fog burns off. Original fir and redwood frames rot from the inside out. We see sills where a screwdriver sinks in like wet cardboard. You can’t set a new IG unit in a rotted frame and expect it to hold true. The frame gets rebuilt first.
- Canyon thermal cycling cracking old glazing seals. The same canyon that holds fog until late morning can push afternoon temperatures past 90°F while Sausalito stays in the 60s. That daily swing is brutal on old dual-pane units. Hardened butyl and aging aluminum spacers crack, argon leaks out, and the window fogs from the inside. A fogged unit can’t be cleaned; the IGU gets replaced, and the new one needs a frame that can handle the next twenty years of temperature swings.
- Hillside sliding door threshold failures. On steep lots throughout Cascade Canyon and the upper Tamalpais neighborhoods, the downhill face of the house often has a sliding glass door at or near soil contact. Original thresholds rot through from constant moisture and redwood duff contact. We probe that threshold with a moisture meter as a matter of course. When we find rot, we cut it out, frame out the opening with pressure-treated blocking, and set the new door on a properly flashed pan before re-hanging the slider.
Pricing for Window Replacement in Mill Valley, CA
Mill Valley window replacement pricing tracks three things: the size and style of the opening, whether the frame needs a full rebuild, and the fire-rated glazing Marin County requires. Our ranges are honest, based on what we’ve actually billed for similar work in 94941.
| Service | Typical Mill Valley Price Per Opening |
|---|---|
| Insert window replacement | $900-$1,700 |
| Full frame replacement | $1,200-$2,800 |
| Storm window replacement | $450-$1,100 |
| Energy-efficient upgrade (low-E tempered) | $1,300-$2,900 |
| Historic window restoration (per sash) | $600-$1,400 |
What moves the number is the opening’s condition, not the contractor’s mood. A square frame with solid sills and a standard double-hung is the low end of the range. A hillside sliding door with a rotted threshold and a fire-rated assembly requirement is the high end. We quote in writing, line by line, before ordering anything. A fixed price with no change orders. Call (888) 635-0804 to schedule a free estimate. We’ll measure, probe, and give you numbers on paper in a day or two.
We Also Serve Cities Near Mill Valley
TruePane’s Window Replacement in Mill Valley team also covers Corte Madera, Larkspur, Sausalito, and Kentfield. If you’re in a flatland neighborhood across the freeway, our Window Replacement crews work across Marin County. Same standards, same Done Right Promise, same live person on the phone at 3 a.m. if it matters.
Serving Mill Valley, CA - Our Local Coverage Area
We’re based in the Mill Valley 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 - Window Replacement in Mill Valley
Yes. Mill Valley sits entirely within California’s Very High Fire Hazard Severity Zone, and Marin County’s WUI ordinances require dual-pane tempered glass, ember-resistant frames with no combustible gaps, and specific door hardware on any replacement window or door that opens onto a yard or hillside. Flatland Corte Madera and Larkspur rarely face the same requirement at the same scale. We pull permits and build to Mill Valley’s ordinance on every replacement, so nothing gets red-tagged at inspection. Call (888) 635-0804 if you want an exact quote on a fire-rated replacement.
Two reasons: the marine layer that stalls in Blithedale and Cascade Canyons keeps wood damp well into late morning, and the redwood canopy above those canyons drips moisture onto sills and jambs for hours after the fog burns off. That sustained dampness penetrates original fir and redwood frames, and rot starts from the inside. Homes in open neighborhoods like parts of Kentfield or Sausalito’s sunny hillsides don’t face the same load. In Mill Valley, we probe every frame before we quote. If there’s rot, we rebuild the frame before we set new glass.
Fog between panes means the insulated glass unit’s seal has failed. In Mill Valley, the biggest driver is canyon thermal cycling: the daily temperature swing from cool marine-layer mornings to 90°F-plus afternoons stresses the sealant and spacer bars until they crack, argon leaks out, and humid outside air gets drawn between the panes. The fix is a new IGU. We replace it and check the frame for the moisture damage that usually accompanies a blown seal. For an exact price on a fogged Mill Valley window, call (888) 635-0804.
Plan on 6-12 weeks for custom windows from order to install, plus a few days for Mill Valley permit review. The lead time is set by the manufacturer’s line, not our labor. On a mid-century contemporary in Cascade Canyon with a failed sliding glass door at soil contact, we locked the price in writing before ordering so the 9-week Andersen lead time didn’t change the final bill. If you need something faster, we keep a stock of common insert sizes and standard IGUs for quicker turnaround. Call (888) 635-0804 and we’ll tell you honestly what the timeline looks like for your project.
Yes, in most cases. Historic window restoration in Mill Valley preserves the original sash, muntins, and trim, replaces the glazing, installs new weatherstripping, and brings the window as close to modern comfort as the original design allows. For homes under Mill Valley’s preservation review, restoration is often the only path that keeps the home’s character intact. We’ve rebuilt original fir sash on bungalows throughout the Old Mill area. Restoration typically runs $600-$1,400 per sash, plus any WUI glazing requirement. For a free site review of your Craftsman windows, call (888) 635-0804.
Text or call (888) 635-0804 for your free Mill Valley window replacement estimate. We’ll measure every opening, probe the frames, and give you honest numbers in writing. The price doesn’t move once we’ve shaken hands.
Written by Dale Kessler, Owner at TruePane Windows & Doors, serving Mill Valley and Marin County.



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