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ES Windows Home Additions & ADU: The Pomona Owner’s Guide
ES Windows home additions and ADU installations in Pomona typically run $45,000-$130,000 for additions and $90,000-$220,000 for detached ADUs, with ES Windows aluminum and vinyl window systems spec’d for the Inland Empire’s heat cycles and Santa Ana wind loads. We stock ES Windows-compatible framing hardware, sill pans, and flashing kits on our Pomona trucks, and most replacement components can be sourced within 24-48 hours if not already on hand. Most owners first notice trouble when the addition’s windows start sticking in their tracks after a hot Pomona summer, or when water stains appear on the drywall beneath ES Windows units that were flashed correctly ten years ago but have since seen sealant fatigue from 110°F attic cavities.
Which ES Windows Models This Applies To
ES Windows operates in two product tiers relevant to Pomona additions and ADUs: the ESW 4000 Series (single-hung and horizontal slider, common in garage conversions and bump-outs) and the ESW 6000 Series (thermally broken aluminum, typically spec’d for full additions where Title 24 compliance matters). The model stamp lives on the glass spacer or the hinge-side jamb label, usually a 6-8 digit code starting with “ESW4” or “ESW6.” Measure the daylight opening, not the frame, if the label’s painted over.
OEM parts from ES Windows carry the full warranty chain but ship from Florida with a 7-10 day lead time. We source equivalent-grade sill pans from DuPont and Grace, and compatible compression seals from Schlegel that match ES Windows’ original specs for pile height and backing width. The aftermarket route saves roughly 15-20% on material and doesn’t void the glass warranty if the installation meets ES Windows’ published clearances. One Pomona-specific gotcha: the ESW 4000 slider track wears faster on south-facing additions because the aluminum rail expands against the nylon rollers every afternoon. We’ve started spec’ing stainless-steel roller upgrades on those exposures after seeing repeat failures in the Phillips Ranch and Lincoln Park areas.
Signs Your ES Windows Home Addition or ADU Is Failing

- Windows stick or jam in their tracks. The nylon rollers flatten or the aluminum rail deforms from thermal cycling. In Pomona’s inland heat, this shows up first on west- and south-facing walls where afternoon temperatures spike 15-20 degrees above ambient.
- Water stains on interior drywall below the window. The sill pan flashing has separated at the corner joints or the end dams weren’t sealed with compatible caulk. ES Windows units depend on proper sill pan integration; the window itself can be fine while the rough opening rots.
- Draft or temperature stratification near the unit. The compression seal has hardened or the interlock weatherstrip has lost its pile density. We check this with a smoke pencil; if the stream bends at the meeting rail, the seal’s done.
- Condensation between glass panes. The insulated glass unit (IGU) seal has failed, allowing moist Inland Empire air into the cavity. This is a full sash replacement, not a field repair, and ES Windows IGUs are sized to 1/8-inch tolerances.
- Frame corners gap or separate. The mechanical fasteners in the thermal break have backed out or the corner keys have cracked from expansion stress. This is structural; the sash or frame needs replacement before the glass loses support.
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AfterReplacement Cost & What’s Included
| Component | Price Range (Installed) | What’s Included |
|---|---|---|
| ES Windows sash replacement (IGU + frame) | $800-$2,400 per unit | Removal, disposal, new sash, sealant, interior/exterior trim touch-up |
| Sill pan & flashing replacement | $450-$1,200 per opening | Rot assessment, DuPont/Grace pan install, WRB integration, water test |
| Roller/track hardware upgrade | $180-$450 per sash | Stainless rollers, rail cleaning, track alignment, lubrication |
| Weatherstrip/seal replacement | $120-$350 per unit | Compression seal, pile replacement, interlock adjustment |
| Full addition window package (reframe) | $8,000-$25,000 | All ES Windows units, rough opening repair, exterior trim, permit coordination |
The spread depends on three things: whether the rough opening is sound (rot repair adds $200-$600 per opening in Pomona’s older stock), whether the original install used nail fins or block frames (block frames require more interior trim work), and whether Title 24 updates are triggered by the permit scope. Under Clause 1 of the Haven Standard, every replacement gets a written price before we touch a tool, and no change proceeds without a signed change order. Our 365-Day Done Right Promise covers the installation and hardware; ES Windows’ glass warranty runs 20 years and transfers to the next owner.
DIY or Call Us?

There’s a short list of checks an owner can safely make: open the sash fully and inspect the sill pan through the frame gap for standing water or debris, run a hand along the interior trim to feel for cold drafts or soft drywall, and photograph the label for model identification. Do not attempt to remove a fixed sash or IGU yourself; ES Windows units are heavy, the clips are under spring tension, and a dropped sash will shatter tempered glass into the room. The thermal break assembly also requires specific shimming; get it wrong and the window racks in the opening, voiding the warranty and creating an air gap you’ll pay to fix twice.
We’ve rescued three Pomona DIY attempts this year alone, one in the Mayfair area where the homeowner cracked the corner key trying to force a sash back in. Measure twice, then we can talk. Call (626) 606-1081 and we’ll bring the right ES Windows-compatible hardware, photograph the condition before we start, and leave you with a documented record of what was found and what was done.
FAQs
ES Windows aluminum frames typically last 25-30 years in Pomona’s inland heat, but the nylon rollers, compression seals, and sill pan sealant need attention at 10-15 years. The thermal break adhesive can degrade faster on south-facing walls where surface temperatures exceed 140°F. Call (626) 606-1081 for an exact condition check - estimates are free.
Roller hardware and weatherstripping can be renewed; failed IGUs and cracked corner keys require full sash or frame replacement. We don’t patch sill pans - the integration with the water-resistive barrier is too critical for a partial fix. Call (626) 606-1081 and we’ll tell you which category you’re in before quoting.
A single sash replacement takes 2-3 hours; a full sill pan and flashing rebuild runs 4-6 hours per opening, plus drying time if rot repair is needed. We coordinate inspections for permitted work and leave the photo record same day. Call (626) 606-1081 to schedule.
We carry compatible rollers, seals, sill pans, and flashing stock for both ESW 4000 and 6000 Series. OEM ES Windows sashes and IGUs ship from Florida with a 7-10 day lead time; we order on confirmation and store at our Pomona facility until install. Call (626) 606-1081 to confirm availability for your model.
Rowan Construction Group Pomona is an independent service provider, not affiliated with ES Windows. We also stock and install parts for KraftMaid, Cambria, and Silestone products.
Ready to get the exact number in writing? Call (626) 606-1081 to schedule your free estimate. We’ll review your ES Windows units, photograph what we find, and deliver a flat written price with a written scope before any work starts - that’s Clause 1 of the Haven Standard, and it’s been our practice since 2007.
Written by Grant Rowan, Owner, Rowan Construction Group Pomona at Rowan Construction Group Pomona, serving Pomona and nearby areas.







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