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CGI Windows & Doors: The Sunnyvale Owner’s Guide
We stock and install genuine CGI-compatible windows and doors in Sunnyvale, with most replacement projects running $4,500-$15,000 for full window replacement and hardware-specific repairs starting around $400-$1,800. Most CGI hardware failures, track issues, and sash problems can be diagnosed and quoted same-day, with parts sourced through our fifty-plus brand network including direct CGI channels. Sunnyvale homeowners usually discover a problem when the window won’t stay open, the lock won’t engage, or they feel a draft along the sill after a Santa Ana wind cycle - signs that the balance mechanism, multipoint lock, or weatherstrip has reached its service limit.
Which CGI Models This Applies To
CGI operates in three main series that you’ll see across Sunnyvale: Estate Collection (aluminum impact), Sentinel (vinyl impact), and WinGuard (the older PGT-integrated line). The part you need depends on which series is installed, and the difference matters - Estate balances are coil-spring assemblies with a 5/8-inch shoe width, while Sentinel uses a block-and-tackle system with a 3/8-inch shoe that looks similar but won’t seat in the opposite jamb.
Check the edge of the sash or the top of the frame for a stamped series mark, or measure the visible glass width and height - Estate frames run 3 1/4 inches deep, Sentinel runs 2 7/8. For hardware, the multipoint lock faceplates are not cross-compatible between series; the Estate uses a 45-degree locking cam, Sentinel uses 90-degree. We source OEM CGI parts where the series is still active, and for discontinued WinGuard hardware we spec quality aftermarket equivalents from Truth or Amesbury that match the mounting pattern and load rating. The decision between OEM and aftermarket comes down to whether the original part is still manufactured and whether the warranty transfer matters for your home’s records.
Signs Your CGI Windows & Doors Is Failing

- The sash drops or won’t stay open. This points to a failed balance mechanism - the coil spring or block-and-tackle that counterweights the sash has lost tension. In Sunnyvale’s dry summers, the lubricant dries and the spring fatigues faster than in humid climates.
- The lock lever turns but doesn’t engage. The multipoint lock’s internal gearbox has stripped, often from forcing the lever when the sash is misaligned. CGI’s Estate series uses a stainless gearbox that corrodes slowly but will eventually bind if the keepers are out of adjustment.
- Visible daylight or air movement at the sash perimeter. The bulb weatherstrip has compressed past recovery or the fin seal has torn at the corner. Santa Clara County’s UV exposure hardens EPDM rubber faster than the manufacturer rates for.
- The rolling screen sticks or derails. The nylon rollers have flattened or the track has accumulated grit and corrosion. Coastal moisture from the Bay, even inland at Sunnyvale’s elevation, accelerates aluminum track oxidation.
- Condensation between the glass panes. The insulated glass unit (IGU) seal has failed, breaking the argon fill and fogging the interior surface. This is not a hardware part but a full sash replacement, and it’s the most common call we get for older WinGuard units in the Lakewood Village area.
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For Sunnyvale, CGI window replacement falls within our standard window replacement range of $4,500-$15,000 for full-frame projects, with hardware-specific repairs at $400-$1,800 depending on the part and access. A balance replacement on an accessible double-hung runs toward the lower end; a failed IGU in a fixed picture window with stucco returns runs higher due to the trim repair and finish matching.
Our written quote breaks out parts, labor, and any subcontractor scope separately - material costs for the CGI-compatible part, labor hours at our standard rate, and a line for permit handling if the replacement triggers Title 24 documentation. Under Clause 1 of the Haven Standard, that price is fixed once signed; no change proceeds without a signed change order. The 365-Day Done Right Promise covers the installation and the part, and you receive a documented photo record of the condition we found and the completed work before we leave.
DIY or Call Us?

There’s a safe middle ground for most CGI hardware issues. An owner can check the series mark, clean the track with a dry brush, and verify that the sash is fully seated in the jamb before calling - about half the “broken” locks we see are simply misaligned sashes that need reseating.
Where DIY goes wrong is the balance replacement. The coil spring in an Estate series carries significant tension, and the block-and-tackle in a Sentinel must be wound to the exact inch-pound rating for that sash weight. Incorrect tension stresses the frame and can release suddenly. We don’t recommend homeowner removal of any spring-tensioned component. Call (650) 405-3637 and we’ll diagnose it, quote it in writing, and handle the replacement with the right tooling and the CGI part or verified equivalent.
FAQs
CGI aluminum frames last 25-30 years with normal maintenance; hardware components typically need attention at 12-18 years in this climate. The Santa Clara Valley’s UV exposure and seasonal humidity swings accelerate weatherstrip and balance fatigue compared to the manufacturer’s baseline. Call (650) 405-3637 for an exact quote on your specific model - estimates are free.
Some multipoint lock gearboxes can be rebuilt, but CGI’s current warranty structure favors complete hardware replacement for anything under fifteen years old. For balances and IGUs, replacement is the only reliable fix - rebuilt balances don’t hold calibration. We stock common CGI hardware on our trucks and can quote both options where rebuilding is viable. Call (650) 405-3637 for an exact quote - estimates are free.
A hardware swap - balance, lock, or roller - takes 1-2 hours per opening once the part is on-site. Full sash or IGU replacement runs 3-4 hours including trim repair and seal verification. We carry common Estate and Sentinel hardware in Sunnyvale; specialty or discontinued WinGuard parts typically arrive in 3-5 business days. Call (650) 405-3637 for an exact quote - estimates are free.
We stock the most common failure items for Estate and Sentinel series: coil balances, block-and-tackle assemblies, multipoint lock sets, and roller kits. IGUs and custom sash components are ordered to spec after measurement. Our sourcing depth across fifty-plus brands, including KraftMaid, Cambria, and Silestone in other trades, means we don’t inflate parts prices to cover uncertainty - the number on the quote is the number we pay. Call (650) 405-3637 for an exact quote - estimates are free.
Rowan Construction Group Sunnyvale is an independent service provider and is not affiliated with CGI Windows & Doors. We source genuine and compatible parts through authorized distribution channels.
Ready to get the number in writing? Call (650) 405-3637 to schedule your free estimate. We’ll identify your CGI series, spec the right part, and deliver a flat written price before any work starts - measure it twice, write it down, then build it.
Written by Grant Rowan, Owner, Rowan Construction Group Sunnyvale at Rowan Construction Group Sunnyvale, serving Sunnyvale and nearby areas.







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