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ECO Window Systems Home Additions & ADU: The San Antonio Owner’s Guide
Adding square footage to a San Antonio home with ECO Window Systems products already in place costs between $45,000 and $130,000, and we handle the framing, finishing, and integration of your existing ECO Window Systems windows and doors so everything lines up and seals correctly. Most homeowners discover the need for this work in one of two ways: either they’re planning an addition or ADU and want the new windows to match what’s already on the house, or an existing ECO Window Systems unit has begun to fail after years of Texas sun and they’re wondering whether to patch it or fold the repair into a larger project. We’ll walk you through what’s actually involved, what it costs in San Antonio, and how to know whether your ECO Window Systems windows are worth keeping.
Key Takeaways:
- Home additions in San Antonio run $45,000 – $130,000; ADU construction runs $90,000 – $220,000 depending on size, site conditions, and finish level.
- ECO Window Systems units are not generic replacements. Their frame depths and mullion profiles must be matched to the existing openings, and we measure every unit before ordering anything.
- We give a written price before any work starts. No line items added after demo day. That’s a Cedarwell Care Promise standard.
- We’re an independent San Antonio remodeling contractor. We’re not affiliated with ECO Window Systems, which means we can install or work around their products without pushing you toward any single brand.
Which ECO Window Systems Models This Applies To
The first thing to know is that ECO Window Systems makes a range of vinyl and aluminum window and door products, and the version you have in your San Antonio home dictates how a home addition or ADU project should be planned. We’ve worked on homes across the city, from Alamo Heights to Stone Oak, where ECO Window Systems units were installed in the last ten to fifteen years. The single hung, double hung, sliders, and casements all have slightly different frame depths, and if your addition is going to tie into an existing wall, the new framing has to account for that dimension rather than assuming a standard rough opening.
Here’s the compatibility reality: ECO Window Systems is not carried by every supply house in San Antonio, so we don’t guess. When you call us about a home addition or ADU, we measure the existing ECO Window Systems units on the house, record the frame depth and glass package, and write that into the scope before finalizing the price. If the new space calls for more windows, we can order ECO Window Systems-compatible units or use a quality equivalent from another manufacturer. The decision comes down to glass package, warranty coverage, and lead time, and we show you the line-item costs for each option before you commit.
We also stock and install window brands like KraftMaid, Cambria, and Silestone for the interior finishes that often accompany an addition, so the entire project can move through one written scope rather than three separate contracts.
Styles & brands we work with
Signs Your ECO Window Systems Home Additions & ADU Is Failing
- Condensation between the glass panes. The seal in the insulated glass unit has failed. In San Antonio’s humidity swings, a failed seal means permanent fogging that cannot be wiped away. The fix is replacement of the glass unit or the sash, not the entire window frame, but the longer it sits the more likely the frame absorbs moisture and warps.
- Visible daylight around the sash when closed. The weatherstripping or the sash itself has sagged. This is common in west-facing windows in San Antonio where afternoon heat cycles stress vinyl. The result is a steady AC leak that shows up on your CPS Energy bill.
- Hard to open or close, or the sash binds on one side. Frame warping or a failed balance in double hung units. Forcing it open wears the lock and the track, and eventually the window won’t seal at all. This matters more when you’re planning an addition because the new space needs to be energy-tight from day one.
- Drafts around the frame even when the sash is fully seated. The installation flashing or the perimeter caulk has degraded, or the frame itself has shifted in the rough opening. This is more common in older San Antonio homes where the foundation has settled, pulling window rough openings slightly out of square.
- Soft wood or water staining on the wall below the window. Water is getting in somewhere above or around the window. On an ECO Window Systems unit this often points to failed sill flashing at the original install. In a home addition, this is precisely the kind of detail we correct before closing up the new wall cavity.
See the difference
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After
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AfterReplacement Cost & What’s Included
For a full home addition in San Antonio that includes new or matched ECO Window Systems windows, our installed projects fall between $45,000 and $130,000. An ADU runs higher, usually $90,000 to $220,000, because it includes a separate foundation, utility runs, a kitchen or bath, and its own window and door package. Window replacement alone, where the existing ECO Window Systems units are swapped out rather than built around, typically lands between $4,500 and $15,000 depending on the number of units and the glass package.
What drives the range: square footage, foundation work (a pier and beam addition costs more to tie into than a slab), the number of new windows and doors, site access, and the interior finish level. A bedroom addition with sheetrock and carpet is the low end. A kitchen extension with custom cabinetry and stone counters is the high end.
Every scope includes the same things: a written price before we start, drop cloths on the floors, shoe covers at the door, quiet tools during your children’s sleep hours where possible, and a photo of the clean-up before the crew leaves. If we’re replacing or adding windows as part of the job, the installed window warranty is written into the contract, and the 365-Day Done Right Promise applies to the entire project. If it’s not done right after the job is complete, we make it right.
DIY or Call Us?
Home additions and ADUs are not DIY projects, and I say that as someone who learned the trade at Los Angeles Trade-Technical College and has spent decades framing and finishing houses. The structural, electrical, plumbing, and window integration work involved is exactly where an untrained hand causes problems that take twice as much money to undo. If you have an existing ECO Window Systems window that’s failing, you can check a few things yourself: look at the caulk line around the exterior frame, check whether the sash sits level, and note whether the lock engages cleanly. Write down what you see. That’s useful information to bring to the phone call.
What you should not do is attempt to reset a window in a rough opening, replace a double hung balance, or pull a window out to “see what’s behind it.” The first two carry real risk of the unit dropping; the third breaks the flashing and water barrier that keep San Antonio’s rain and heat out of your wall. Call us at (432) 233-0976 and we’ll send a background-checked, uniformed technician to look at the actual window and the wall around it, write down what we find, and give you a price. Write it down, price it once, do it right.
FAQs
In our experience, ECO Window Systems units in San Antonio last roughly 15 to 20 years before the seals or hardware begin to fail, with west-facing windows wearing out faster due to direct afternoon sun and heat cycling. Homes with heavy shade from live oaks tend to get more life out of the same products. Call us at (432) 233-0976 and we’ll tell you honestly whether a repair or a replacement makes more sense for your situation.
Yes, in many cases. Failed glass units can be replaced, weatherstripping can be renewed, and balances can be swapped, often for a few hundred dollars per window. The exception is a warped or water-damaged frame, which generally means full replacement. Call (432) 233-0976 and we’ll measure and diagnose the issue before quoting any repair or replacement work.
A standard bedroom or living room addition in San Antonio takes roughly 10 to 16 weeks from the first day of construction, and an ADU takes 5 to 9 months depending on utility connections and permitting. Every scope we write includes a schedule with milestones, and we keep you updated on any weather delays as they happen. Call (432) 233-0976 for a free estimate and a realistic timeline for your specific project.
We keep common weatherstripping, locks, and balance components for major vinyl window lines on our trucks, but ECO Window Systems-specific hardware is not always stocked locally and may need to be ordered. We’ll tell you at the estimate visit whether your repair can be done same-visit or whether we need a second trip for parts. Call (432) 233-0976 to schedule a visit and find out what your window actually needs.
Written by Graham Stein, Owner, Elmstead Remodeling San Antonio at Elmstead Remodeling San Antonio, serving San Antonio and nearby areas.
