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Therma-Tru Windows & Doors: The Pomona Owner’s Guide
We stock and install Therma-Tru-compatible windows and doors across Pomona, with typical replacement projects running $4,500-$15,000 for window replacement and $8,000-$25,000 for impact window installation depending on series and opening count. Most standard-size Therma-Tru entry door and window units are available same-day through our supplier network, and we carry common hardware, seals, and sash components on our trucks. Most Pomona homeowners first notice a problem when the multipoint lock won’t engage smoothly, or when they feel a draft along the jamb that wasn’t there last season.
Which Therma-Tru Models This Applies To
Therma-Tru organizes its door lines by material and performance tier, and the parts are not interchangeable across series. We regularly service Classic-Craft (fiberglass with wood-edge construction), Fiber-Classic (smooth or textured fiberglass), and Smooth-Star (paint-ready fiberglass) entry door systems in Pomona. For windows, we see the Direct Set, Tilt-and-Turn, and replacement sash series most often in local homes built between 2005 and 2020. The part number you need is stamped on the hinge edge of the door slab or on a label inside the top track of a window unit, usually a 6- to 10-digit code starting with the series prefix. If that label is painted over or sun-faded, we measure the daylight opening, jamb depth, and wall thickness to cross-reference.
OEM parts from Therma-Tru ship with exact color and profile matching, which matters on stained or custom-painted units where a slight fiberglass texture difference reads across a front entry. Quality aftermarket equivalents exist for hardware and weatherstrip, but we source OEM threshold caps, multipoint locking mechanisms, and compression seals because the tolerances are tight, a half-millimeter variance in a door sweep channel will whistle in a Santa Ana wind. We keep multipoint lock replacement kits and common hinge pin sets stocked for Classic-Craft and Fiber-Classic in our Pomona warehouse.
Signs Your Therma-Tru Windows & Doors Is Failing

- Draft along the jamb or sill. The Q-Lon or silicone bulb seal has compressed past recovery, or the corner joints in the weatherstrip have separated. On south- and west-facing doors in Pomona, UV exposure accelerates this, we see it first on units without porch overhangs.
- Multipoint lock sticks or won’t fully engage. The gearbox inside the mortise mechanism has worn teeth, or the keepers have shifted as the frame settled. A lock that requires shoulder pressure to close is telling you the mechanism is out of tolerance.
- Visible moisture between glass panes. The insulating glass unit (IGU) seal has failed, the desiccant inside the spacer bar is saturated, and the glass pack needs replacement. This is not a frame issue, but it is a Therma-Tru-specific sizing problem if the sash was custom-sized.
- Door slab rubs the frame or threshold. Hinge screws have backed out, the frame has racked slightly, or the composite bottom rail has absorbed moisture and swelled. In Pomona’s older neighborhoods with concrete slab settlement, we see this on 8-foot fiberglass doors where the header has dropped a quarter inch.
- Condensation or staining on the interior sill. The weep holes in the exterior sill cap are blocked with debris, or the sill pan flashing was omitted during original installation. Water follows the path of least resistance and shows up inside.
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AfterReplacement Cost & What’s Included
For Therma-Tru window and door replacement in Pomona, our installed pricing runs $4,500-$15,000 for standard window replacement and $8,000-$25,000 for impact-rated window installation, with entry door systems typically falling in the $3,500-$8,500 range depending on sidelite configuration and glass option. Single-component repairs, a multipoint lock replacement, IGU swap, or weatherstrip renewal, run $180-$650 including labor and the OEM part.
What drives the range: unit size, whether the frame is intact or needs full removal, stucco or siding repair scope, and whether the original was a custom size that now requires a made-to-order replacement. Under Clause 1 of the Haven Standard, we deliver a written price before any work starts, line-itemed by labor, materials, and any wall repair or trim package. Every Therma-Tru installation carries our 365-Day Done Right Promise, if it is not done right, we make it right. The photo record from your visit documents condition before and after, included as standard.
DIY or Call Us?

There is a safe middle ground here. A homeowner can clear weep holes with a pipe cleaner, tighten visible hinge screws, and verify that weatherstrip is fully seated in its kerf. These are maintenance tasks, not repairs.
Where DIY goes wrong: multipoint lock mechanisms contain spring-loaded deadbolts and hook bolts under tension, improper removal can launch components or damage the mortise pocket in a fiberglass door slab. IGU replacement requires vacuum lifting equipment and a clean-room environment for seal integrity, a scratched glass surface or failed perimeter seal means doing the job twice. And any work that disturbs the flashing or sill pan risks water intrusion behind the stucco, which in Pomona’s sun-baked exterior walls can go undetected until the damage is structural. We are an independent service provider, not affiliated with Therma-Tru, and we carry the liability and the warranty on the install. Call (626) 606-1081 to schedule your free estimate.
FAQs
Fiberglass door skins typically perform 25-30 years in Southern California’s dry heat, though the weatherstrip, lock hardware, and threshold cap need attention every 7-12 years. The UV exposure on unshaded west-facing units accelerates seal degradation, we see earlier hardware wear on those orientations. Call (626) 606-1081 for an exact quote, estimates are free.
No. Once the desiccant is saturated and the seal has failed, the insulating gas is gone and cannot be reintroduced in the field. The glass pack must be removed and a new IGU fabricated to the exact sash dimensions. Call (626) 606-1081 for an exact quote, estimates are free.
A standard entry door replacement, including frame removal and trim, is typically one day. A full-frame window replacement runs one to two days per opening depending on stucco repair scope. Custom-size orders add 3-4 weeks for manufacturing. Call (626) 606-1081 for an exact quote, estimates are free.
We carry multipoint lock kits, hinge pin sets, compression seals, and threshold caps for Classic-Craft and Fiber-Classic series on our Pomona trucks. IGU replacements and full door slabs are ordered to specification after measurement. Call (626) 606-1081 for an exact quote, estimates are free.
Measure twice, then we can talk. Grant Rowan and our crew have been working across Pomona since 2007, from the Fairplex corridor to downtown-adjacent commercial jobs, and we’ve learned that a Therma-Tru door that doesn’t close right is usually telling you something specific if you know how to read it. We document what we find, quote what it costs, and fix what we quoted.
Written by Grant Rowan, Owner, Rowan Construction Group Pomona at Rowan Construction Group Pomona, serving Pomona and nearby areas.







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