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ES Windows Home Additions & ADU: The San Antonio Owner’s Guide
Adding square footage to a San Antonio home with ES Windows products already in place means matching new window packages to what you’ve already got. A home addition or ADU (accessory dwelling unit) runs $45,000 to $130,000 for typical San Antonio builds, and the window selection is one of the first decisions that locks in your energy costs and curb appeal for decades. Most owners call us after realizing their existing ES Windows can’t simply be “matched” at a big-box store, or after a builder told them the lead time on new ES Windows would delay their project by months. We stock and install ES Windows-compatible packages for additions and ADUs across San Antonio, and we write the price down before any work starts.
Here’s the honest picture: if you’re adding a room or building a detached ADU in San Antonio, your window package will run roughly 10% to 18% of the total project cost depending on opening sizes, glass packages, and how many windows you’re actually adding. The smartest move is to lock the window spec early, because framing dimensions, rough openings, and exterior trim all get built around the windows, not the other way around.
Key Takeaways
- Home additions and ADUs in San Antonio typically cost $45,000 – $130,000 (ADU construction alone often runs $90,000 – $220,000 depending on size and site conditions).
- ES Windows are still manufactured to order, so lead times matter. Plan the window package before framing begins.
- Mason Remodeling Co San Antonio is an independent service provider. We are not affiliated with ES Windows, but we install and supply compatible ES Windows products.
- We deliver a written price before any work starts. No verbal estimates that grow on the final bill.
- Every crew member is background-checked, identity-verified, and you get their name and photo before they arrive. That’s the Threshold Standard.
Which ES Windows Models This Applies To
ES Windows makes fixed, casement, awning, sliding, and tilt-turn window lines used in both new construction and replacement work. The two series we most often specify for San Antonio additions and ADUs are the ES 3000 Series (narrower frames, narrower sightlines, typically used in mid-range residential work) and the ES 7000 Series (heavier profiles, higher wind-load ratings, often required on second-story additions or units closer to the coast). If you’re matching an existing ES Windows product from a prior build, the frame profile and glass package are already set. The rough opening dimensions are what drive the order.
Here’s the compatibility gotcha most owners don’t know until it’s too late: ES Windows frames from different manufacturing years may not share identical exterior trim profiles. If you’re adding onto a 2012 home that used ES Windows, do not assume the 2026 version of the same “model” will butt seamlessly against the old exterior trim. The glazing bead depth, frame depth, and even the corner joinery changed over production runs. We measure the existing windows before the addition is framed, because this determines whether we match, re-trim, or replace the adjacent existing windows to keep the wall plane consistent.
For ADUs, which in San Antonio often run 400 to 800 square feet, homeowners usually choose new ES Windows throughout rather than attempting to match a main house. That’s the cleaner path. Rough openings get built to the window spec, and we don’t have to deal with 14 years of paint buildup on old trim.
OEM versus aftermarket: ES Windows parts and window units are sold through authorized distributors. When we install ES Windows products, we source them as new, factory-ordered units. We do not use aftermarket glass packages or aftermarket hardware in ES Windows frames. If a hardware component fails down the line, ES Windows hardware is the only thing we put back in that frame. Generic replacement hardware from a hardware aisle tends to bind, strip, or fail to seat correctly in ES Windows’ specific milled channels. We’ve seen too many window cranks snapped off by owners who forced a close-enough handle onto an ES Windows operator. Close-enough is not a thing with this brand.
In addition to ES Windows, we regularly supply KraftMaid and Cambria and Silestone products when a San Antonio addition includes a kitchen or wet bar, so the window package and the cabinet package can be coordinated through one contractor with one written price.
Styles & brands we work with
Signs Your ES Windows Home Additions & ADU Is Failing
- Condensation fogging between the panes of existing ES Windows. The insulated glass unit (IGU) seal has failed. Once that seal goes, the gas fill escapes and the glass loses its thermal performance. In San Antonio’s summer humidity, a failed IGU will fog every morning and clear slowly through the day, then fog again overnight.
- Visible daylight or a breeze at the sash corners when the window is closed and locked. The weatherstripping has compressed or the sash has shifted slightly out of square. On an addition, this usually shows up within the first three years if the rough opening wasn’t perfectly plumb and level.
- Crank-operated casements that slip, grind, or spin without moving the sash. The operator gear inside the frame has stripped. ES Windows operators are built into the frame, so the fix is hardware replacement, not lubrication. Forcing the crank just destroys the gear teeth faster.
- Water staining on the interior drywall below a window sill. The sill pan flashing underneath the window was either missing or incorrectly lapped during the addition’s original construction. San Antonio sees intense, wind-driven rain in spring and fall. A window that “never leaked” in the dry season will tell you everything in a thunderstorm.
- Sashes that stick in summer and loosen in winter. This is classic San Antonio behavior for an improperly specified window. Vinyl and aluminum expand and contract at different rates. If the window was installed too tight to the rough opening, seasonal movement binds the frame. Your addition’s windows should not require a shoulder to open in August.
See the difference
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AfterReplacement Cost & What’s Included
For a typical San Antonio home addition or ADU, the window package installed runs $4,500 to $15,000 depending on how many openings and which ES Windows series you choose. That’s inside the broader addition budget of $45,000 – $130,000. If you’re replacing failed windows in an existing ES Windows home rather than building new, window replacement in San Antonio runs $4,500 to $15,000 for a full-house package. Impact-rated ES Windows for an ADU or addition near high-wind zones pushes toward the upper end, $8,000 to $25,000 for a complete package.
Here’s the line-item breakdown we give San Antonio homeowners before they sign anything:
- ES Windows units (factory-ordered to rough opening specs): 40% to 55% of the window budget
- Installation labor (removal of failed units, sill pan flashing, shimming, insulation, trim, interior and exterior sealing): 30% to 40%
- Flashing, sealants, trim, and disposal: 10% to 15%
Every quote is written. That means the number on the page is the number you pay, including all labor, materials, and disposal, unless you change the scope. We don’t do change orders because we didn’t do the measuring right the first time. If the price changes at all, it’s because you added something.
All of our window and addition work carries the 365-Day Done Right Promise: if the work isn’t right within a year of the completion date, we make it right at no cost to you. That guarantee is written into every project. And if a repair or installation fails, the second visit is free. No dispute process. No deductible. No “well, that’s wear and tear.” Call us, we come back, we fix it.
DIY or Call Us?
There are a few things a San Antonio homeowner can safely check before calling us. Open and close every window in the addition or ADU and note which ones bind, which cranks slip, which panes have fog. Look at the caulking bead where the exterior frame meets the stucco or siding: if it’s cracked, pulling away, or missing entirely, that’s a water intrusion point. Take photos of the interior and exterior of each problem window. That gives you a record and gives us a head start.
What you should not do is attempt to replace the glass unit, the operator hardware, or the window itself. ES Windows units are heavy. A fixed picture window in a San Antonio addition can weigh over 100 pounds. Removing it from the frame without scoring the perimeter seal correctly means it comes out in shards, not in one piece. And every ES Windows installation needs proper sill pan flashing underneath, or the first hard rain becomes a drywall repair on the inside of your new addition. That’s the failure we see repeatedly from handyman installations: the window looks fine for eight months, then March thunderstorms come through San Antonio and the wall underneath the window is stained for the rest of its life.
Know who’s coming, know what it costs, know it’s covered – that’s the whole job before the job starts. Call (254) 269-5071 and we’ll measure the openings, match the ES Windows series you already have (or spec new ones for your ADU), and put the price in writing before a tool leaves the truck.
FAQs
Properly installed ES Windows in San Antonio typically last 20 to 30 years before the frame or glass package needs serious attention. The insulated glass seal is usually the first thing to fail, often between years 12 and 18, which shows up as fogging between the panes. Extreme San Antonio sun exposure on west-facing walls shortens that lifespan; shaded east and north exposures stretch it. Call (254) 269-5071 for an exact assessment of your specific windows.
In many cases, yes. If the frame is square and undamaged, we can replace the insulated glass unit or the operator hardware without replacing the entire window. If the frame itself is warped, the weatherstripping channels are broken, or the frame was incorrectly flashed during the original installation, replacement becomes the honest recommendation. We’ll tell you which applies to your windows before you spend a dollar.
For a new addition or ADU, window installation happens inside the broader construction schedule and usually takes one to three days of dedicated window work once framing is complete. If we’re replacing existing failing ES Windows, a full typical house runs two to four days from removal to final sealing. Factory order lead times for ES Windows units are a separate timeframe we confirm before we write your quote.
ES Windows units are factory-ordered to your measured rough openings; we don’t keep pallets of unassigned units in a warehouse. We do keep ES Windows-compatible installation materials on the truck: sill pan flashing, backer rod, sealants, and fasteners. And we keep a small stock of common ES Windows replacement hardware for quick fixes when we already know your model from a prior job. Call (254) 269-5071 and we’ll confirm what applies to your project.
For a free estimate on your San Antonio home addition, ADU, or ES Windows window replacement, call (254) 269-5071. A live person answers. We’ll schedule the measure, send the written price, and every crew member who arrives at your door will already be introduced to you by name and photo before the visit.
Written by Isaac Pruett, Owner, Mason Remodeling Co San Antonio at Mason Remodeling Co San Antonio, serving San Antonio and nearby areas.
