ECO Window Systems Home Additions & ADU Nationwide

ECO Window Systems Home Additions & ADU: The Los Angeles Owner’s Guide

Home additions and ADUs built with ECO Window Systems products in Los Angeles typically run $53,100 – $153,400 depending on square footage, foundation work, and how much of the existing structure ties into the new build. We stock the window, door, and glazing components to match your existing ECO Window Systems installation, and we can usually have the right parts on site within a few days. Most owners discover a problem during a remodel inspection: a window that no longer closes flush, a door frame that’s shifted, or glass that’s fogged between panes after a few hot Valley summers.

Call (936) 259-2607

Trevor Nash started Penhallow Remodeling after too many years of watching homeowners get handed vague estimates for additions and ADUs that doubled by the time framing started. The way we approach an ECO Window Systems addition or ADU project is the same way we approach every job: written price first, real arrival window, and a 365-Day Done Right Promise in writing before the first wall goes up. That matters a lot when you’re spending north of $50,000.

Which ECO Window Systems Models This Applies To

ECO Window Systems has gone through several series changes over the years, and parts are not always backward compatible. The labeling matters. Look for the silver or white sticker on the inside frame of the window or door, usually on the hinge side. You’ll find a series code and a glass package designation, something like “ECO-3” or “ThermalPro,” depending on the year. If the sticker’s gone, pull one sash and check the spacer bar between the glass panes: older ECO Window Systems units used an aluminum spacer, newer ones use a warm-edge foam spacer, and that simple difference tells us which generation you have.

Here’s the gotcha we see all the time in Los Angeles: an owner replaces one window with a newer ECO series and expects it to match the rest. It won’t. The frame depth changed by 3/16″ between generations, and the lock hardware doesn’t transfer. For additions and ADUs, we always verify the existing series before ordering. You have two paths: OEM parts (matched exactly, pricier, longer lead time) or quality aftermarket equivalents from brands like KraftMaid for cabinetry and Silestone or Cambria for countertop surfaces that integrate with the window package. For the glazing and frames themselves, we recommend OEM on matching work and we’ll tell you honestly when aftermarket is just as good.

Penhallow Remodeling is an independent Los Angeles contractor, not affiliated with ECO Window Systems. We carry and install their product lines because the quality holds up in Southern California’s heat and the parts availability is consistent.

Signs Your ECO Window Systems Home Additions & ADU Is Failing

• Window sashes won’t stay open or closed. The spring balance or pivot bar has failed, common after 8 – 12 years in Los Angeles because heat cycles break down the nylon components inside the frame.
• Condensation trapped between glass panes. The IGU (insulated glass unit) seal has failed. Once the desiccant inside the spacer bar is saturated, the fog never clears, and the unit needs replacement.
• Sliding door tracks are binding or grinding. Dirt, sagging rollers, or a failed alignment block. James Hardie siding work or stucco patch jobs on the addition can shift the rough opening just enough to pinch the track.
• Air leaking around the frame during Santa Ana winds. The weatherstripping or the exterior flashing has pulled away. In older ECO installations, the original foam tape deteriorates after about six Los Angeles summers.
• Lock hardware misaligns after the structure settles. Los Angeles soil moves. Clay-heavy ground in the Valley expands and contracts, and the addition’s framing shifts enough that the strike plate no longer lines up by a fraction of an inch.

Replacement Cost & What’s Included

For ECO Window Systems components within a home addition or ADU project, full window and door package replacement in Los Angeles runs $5,310 – $17,700 depending on how many openings and which series you have. A full home addition with ECO Window Systems windows, doors, and glazing runs $53,100 – $153,400, while a standalone ADU with the same product line runs $106,200 – $259,600. The spread comes from foundation scope, utility connections, and how far the existing structure has to be tied in.

Every price we write includes the parts, the labor, the disposal, and the written guarantee. You’ll know the number before any work begins, and it won’t change unless you change the scope. That’s the Kingswell standard Trevor’s operated under since 2004.

DIY or Call Us?

You can clean the tracks, tighten visible screws on hardware, and check whether the weep holes at the bottom of the frames are clear. Beyond that, this work gets dangerous fast. Window sashes on larger ECO units weigh 40 – 80 pounds, and the spring balances carry enough tension to snap back hard if released incorrectly. Glass replacement on a second-story addition is not a ladder job. If the issue is in the rough opening, the framing, or the glazing itself, call us at (936) 259-2607 and we’ll send a background-checked, uniformed technician to assess it. The estimate is free.

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