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ES Windows Home Additions & ADU: The San Antonio Owner’s Guide
Planning a home addition or ADU in San Antonio with ES Windows products already in place, or planning to spec them into the new build, comes with a specific set of questions about compatibility, cost, and timeline. A full home addition in San Antonio typically runs $45,000 to $130,000, while an ADU construction project lands between $90,000 and $220,000, depending on square footage, foundation work, and the window package you choose. We stock and install ES Windows-compatible units for additions and ADUs, and we’ll match the existing glass, frame color, and hardware so the new space doesn’t look like an afterthought.
The way most San Antonio homeowners realize their ES Windows plan has a problem is mid-project, when they discover the original window specs don’t match the new addition’s structural requirements, the frames they ordered won’t pass local code, or the ADU needs a different energy rating than the main house. The good news is these are solvable problems if you catch them before drywall goes up. The bad news is they’re expensive to fix after inspection fails.
Key Takeaways:
- We install ES Windows-compatible units for additions and ADUs across San Antonio
- Full addition work: $45,000 – $130,000; ADU construction: $90,000 – $220,000
- Written price before any work starts, per The Relay Visibility Guarantee
- Luca Romano and our crew handle the window spec, framing, and install as one job
Which ES Windows Models This Applies To
ES Windows makes several product lines, and the compatibility question depends on which one you’re working with. The key lines for San Antonio additions and ADUs are the ES 900 Series, the ES 700 Series, and the ES 400/450 Series. The 900 Series is their heavier aluminum thermally broken frame, which shows up a lot in custom homes and higher-end additions. The 700 Series is a mid-range aluminum frame that works well for ADUs and garage conversions. The 400/450 Series is the budget-friendly aluminum line, and it’s common in older San Antonio homes from the 1990s and 2000s.
Here’s the compatibility gotcha most people miss: ES Windows changed their frame extrusion profiles around 2016. Older units (pre-2016) use a narrower mullion with a different glazing bead than the current production. So if you’re adding onto a house built in 2010 and you order current-model ES Windows to match, the sightlines won’t line up. We verify the actual extrusion profile before ordering, because matching “close enough” windows on an addition looks wrong from the street and it’s the first thing a sharp-eyed buyer notices when you eventually sell. For OEM versus aftermarket, we recommend OEM ES Windows frames for additions where the new windows will sit adjacent to existing ones. For a standalone ADU, a quality aftermarket equivalent with matching U-factor and SHGC ratings works fine and can save 15 to 20 percent.
Styles & brands we work with
Signs Your ES Windows Home Additions & ADU Is Failing
If you’re reading this because you already have an addition or ADU with ES Windows and something’s off, here’s what we see most often in San Antonio:
- Condensation between the panes. The seal has failed and the insulating gas has leaked out. Once that happens, the unit’s energy performance drops and the only real fix is glass replacement or a new sash. San Antonio’s heat makes this worse because the temperature differential between inside and outside is extreme from May through September.
- Frames that won’t close flush against the jamb. This usually means the frame has shifted due to foundation movement. San Antonio’s clay soil expands and contracts with moisture, and additions built on slab foundations are especially prone to this. The window isn’t the problem; the structure under it is.
- Rollers that grind or skip when you slide the window. ES Windows uses nylon rollers that wear down over time, especially on larger slider units. Once the roller wheel flattens, the sash drags on the track and eventually scores the aluminum.
- Foggy glass in the morning, clear by afternoon. This is early-stage seal failure. It means moisture is getting into the airspace but hasn’t condensed permanently yet. Don’t wait; once the desiccant inside the spacer saturates, the fog becomes permanent.
- Water stains on the interior drywall under the window. This is either a failed exterior seal or improper flashing during the original install. We see this a lot on ADUs where the builder rushed the window flashing to hit a deadline. Water intrusion around windows in San Antonio’s heavy spring rains leads to mold and rot fast.
See the difference
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AfterReplacement Cost & What’s Included
For a home addition or ADU in San Antonio where ES Windows units are going in, here’s the honest price picture. Full home addition work runs $45,000 to $130,000, and that number includes the windows but not as a line item most builders want to talk about. When we tackle a window package as part of an addition, typical ES Windows-compatible window costs run $450 to $1,100 per opening for standard sizes, depending on the series and glass package. An ADU with six to eight windows usually carries a window budget of $3,500 to $9,000 of the overall project cost.
What drives the range: window count and size, whether you’re matching existing ES Windows profiles (which sometimes means custom-ordered mullions and trim), the glass package (double-pane low-E versus triple-pane), and whether the structure needs header work to support larger openings. Every quote we write includes materials, labor, flashing, trim, and disposal. The number on our written estimate is the number you pay, per The Relay Visibility Guarantee. No change orders, no surprise line items at the end. We back the install with our 365-Day Done Right Promise: if the window install isn’t right, we come back and make it right, in writing.
DIY or Call Us?
For window-related work in an addition or ADU, there’s a clear line. You can safely clean tracks, inspect for visible seal cracks, and check caulk beads. You shouldn’t pull a window frame out of a wall yourself. Window removal and reinstallation on a home addition or ADU in San Antonio involves structural headers, flashing that has to be layered correctly, and waterproofing details that fail quietly when done wrong. We’ve seen DIY window swaps where the homeowner sealed everything from the inside and didn’t flash the exterior, and the first hard rain found the gap. That’s a $3,000 repair that started as a $400 window.
If you’re mid-project on a San Antonio addition or ADU and the window package isn’t right, call us at (432) 547-6806. We’ll come look, tell you what you actually need, and put a written price in your hands. As Luca Romano says, the craft comes first. Everything else follows.
FAQs
ES Windows aluminum frames typically last 20 to 30 years in San Antonio, but the glass seals usually fail between 10 and 20 years due to our extreme heat cycling. The frames hold up; the seals are the weak point. If you’re planning an addition or ADU, spec the newer thermally broken frames and budget for glass replacement somewhere around year 15. Call (432) 547-6806 for current pricing on ES Windows-compatible options.
Yes, sometimes. Failed glass seals can be addressed with a new insulated glass unit (IGU) installed into the existing frame, which runs less than full window replacement. But if the frame itself is warped, corroded, or the extrusion profile is the older pre-2016 style, replacement is the better long-term call. We’ll tell you which one makes sense for your San Antonio home before you spend a dime.
For a standard addition or ADU window package, installation takes two to five working days once the windows arrive on site. Custom-ordered ES Windows-compatible frames can add two to four weeks to the timeline, so we order those early in the project. We coordinate with your framing schedule so windows go in as soon as the openings are ready. Call (432) 547-6806 to get a written timeline and price for your specific project.
We stock common ES Windows-compatible hardware, rollers, locks, and weatherstripping on our trucks, and we order full window units directly from ES Windows and vetted aftermarket suppliers for additions and ADUs. We also work with KraftMaid, Cambria, and Silestone for the interior finishes on home additions, so the window package and the cabinetry and countertops all come together under one written price and one schedule.
No. The written price we give you before work starts is the price you pay at the end. If we find an issue mid-project, like a header that needs reinforcement or unexpected framing damage, we document it, show you photos, and get written approval before any additional cost is added. No surprise invoices, no “while we’re here” add-ons. That’s The Relay Standard, and it’s how we’ve operated in San Antonio since 2005.
If you’re planning a home addition or ADU in San Antonio and you need ES Windows-compatible units priced and installed correctly, call (432) 547-6806 or reach out to our team. We’ll give you a free estimate with a written price, a clear timeline, and the name of the technician who’ll be on site before they arrive. That’s the only way we work.
Written by Luca Romano, Owner, Sawyer Remodel San Antonio at Sawyer Remodel San Antonio, serving San Antonio and nearby areas.
