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ES Windows Home Additions & ADU: The Santa Clarita Owner’s Guide
If you’re planning a home addition or ADU in Santa Clarita with ES Windows specified, expect the window package for a full addition to run between $45,000 and $130,000 installed, depending on the number of openings, glass package, and whether the project involves structural changes. We help Santa Clarita homeowners match the right ES Windows series to their addition, order correctly, and get them installed so the house stays comfortable through our hot summers and cool canyon nights. Most owners come to us after realizing their existing window package won’t extend cleanly into the new space, or when a builder-grade window in an older addition has failed and they want to upgrade to something that holds up better in the Santa Clarita Valley sun.
This page covers what you need to know before spending money on ES Windows for a home addition or ADU in Santa Clarita, including compatibility, pricing, and what actually fails first. We stock and install ES Windows-compatible products for additions and ADUs throughout Santa Clarita, Valencia, Saugus, Canyon Country, and Newhall.
Which ES Windows Models This Applies To
ES Windows are built in Thailand and distributed through select dealers in the U.S. The product line splits into several series: the ES70, ES65, ES60, and the heavier commercial-grade ES90 and ES100 lines. For Santa Clarita additions and ADUs, the ES70 and ES65 are the most common choices because they balance cost against the thermal performance you need when daytime temperatures push past 100°F in Stevenson Ranch or Sand Canyon. The frames are thermally broken aluminum with polyamide strips, which matters more than people expect in our climate because the temperature differential between the outside glass and inside air is extreme from June through September.
One compatibility gotcha we run into regularly: ES Windows’ mullion and clip systems changed between older production runs and current stock. If you’re trying to match windows in an existing addition, the exterior sightline may not align perfectly with windows bought five years apart, even in the same series. We always recommend pulling the label from the jamb or head of an existing window and photographing it before ordering anything. That label carries the series, glass spec, and production batch. Without it, guesswork gets expensive.
On the OEM-versus-aftermarket question: glass units for ES Windows are replaceable by local glass shops that stock matching low-E and spacer options, but the frames, hardware, and weatherstripping should be OEM ES product. Aftermarket hardware often fits, but the lock geometry and weatherseal compression change, and you’ll feel the draft or hear the rattle within a season. We also work with other brands on addition and ADU projects where the homeowner wants flexibility, including KraftMaid for cabinetry in the new space, and Cambria or Silestone for countertops in an ADU kitchenette.
Styles & brands we work with
Signs Your ES Windows Home Additions & ADU Is Failing
- Condensation between the glass panes. The desiccant in the spacer has saturated, and the sealed unit has lost its argon or krypton fill. In Santa Clarita’s dry climate, this usually means a failed edge seal, not high indoor humidity. The fix is a new insulated glass unit, not a whole window.
- Fogging that comes and goes with the weather. Intermittent fogging is often the start of seal failure. It clears on cool mornings and fogs on hot afternoons because the trapped air expands and contracts. Once you see it more than twice, the unit is on borrowed time.
- Visible moisture or mineral staining on the lower inside corner of the frame. This points to weep hole blockage or a failed corner seal on the frame itself, which is more serious than a glass unit issue. We see this most often on ADU windows that face sprinkler overspray in Santa Clarita.
- Hard-to-turn handles or latches that won’t catch. ES Windows hardware wears with repeated use, particularly on casement and awning windows. If you have to lift the sash or push from outside to get the lock to engage, the hinge or locking mechanism is failing and should be evaluated.
- A draft you can feel on windy days, especially along the top rail. Weatherstripping loses compression over time. Santa Clarita’s Santa Ana winds will find any gap. Replacing weatherstripping is inexpensive; ignoring it drives up cooling costs and lets dust and insects in. If the draft persists after new seals, the frame may have racked or the sash needs adjustment, which means a window pro, not a DIY fix.
Replacement Cost & What’s Included
For a home addition or ADU in Santa Clarita, the full project cost with ES Windows and all associated framing, drywall, electrical, flooring, and finish work runs $45,000 to $130,000 for the addition side, with ADU construction ranging from $90,000 to $220,000 depending on site conditions, utility connections, and the level of finish. If the scope is narrower, like replacing windows in an existing addition rather than building new, the window package alone typically runs $8,000 to $25,000 for impact-rated product, which matters in parts of Santa Clarita where wind-driven debris is a real concern.
We give you a written price before any work starts, every time. That price breaks down materials, labor, and any permit or engineering line items. You’ll see the ES Windows series and glass spec named on the quote, so you can verify pricing with another dealer if you want. The workmanship warranty on our installs covers the labor, and the ES Windows product warranty covers the frames and glass per their published terms. That’s how it should work: you know exactly what’s on the paper before the first board goes down.
See the difference
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AfterDIY or Call Us?
There are things you can safely check yourself: look for the manufacturing label on the jamb or head, document any condensation pattern with photos, and test each lock and hinge gently. Understanding what you have before you call saves everyone time and helps us give you a straight answer over the phone. What you should not do is remove an ES Windows sash from its frame without marking the hardware positions, force a stuck lock, or try to reseal a glass unit with silicone from the outside. Once a sealed unit has failed, no caulk or film on the market will restore the thermal performance. And on a second-story addition window, the risk of a fall while trying to work from a ladder is not worth the money you’d save. Call us at (661) 542-4056 and we’ll come take a look, measure what’s there, and give you a written price.
FAQs
In our experience, the frames on ES Windows hold up 20 to 30 years with basic cleaning and occasional hardware lubrication. The glass units themselves typically last 12 to 20 years in Santa Clarita’s heat and UV exposure, with anything facing south or west losing its seal first. We’ve replaced glass units in otherwise perfect ES frames after 15 years.
Yes, in many cases: glass units, weatherstripping, locks, hinges, and handles can all be repaired or replaced individually without removing the frame. That’s the advantage of ES Windows’ construction. A full frame replacement is only needed when the frame itself is damaged or racked. We’ll tell you which one you’re dealing with before any money changes hands.
Most single-window part replacements, like a lock, handle, or weatherstrip, take under two hours on site. A glass unit replacement takes one to two weeks from measurement, because the unit is ordered to the exact size and spec. New construction for an addition or ADU follows the schedule we lay out in the written estimate, which you’ll have before work begins.
We keep common ES Windows hardware and weatherstripping on the truck for the most frequent failure points. Glass units are drop-shipped directly to the shop with the original ES spec stamped on the packing list. Frames and sashes for new construction are ordered per project and delivered to the Santa Clarita job site once the opening dimensions are confirmed.
Talk to Us Before You Order Anything
If you have an ES Windows product that’s failing, or you’re planning a home addition or ADU in Santa Clarita and want windows that hold up to the valley heat, call us. We’ll walk through what you have, what you need, and what it will cost, in writing, before you commit to anything. That’s the way Graham Stein runs every job. Call (661) 542-4056 for a free estimate.
Written by Graham Stein, Owner, Elmstead Remodeling Santa Clarita at Elmstead Remodeling Santa Clarita, serving Santa Clarita and nearby areas.
