Single hung
Double hung
Horizontal roller
Casement
Bay & bow
Sliding glass doors
Entry doors
Impact garage doors
PGT
CGIFree in-home measure and quote - PGT, CGI and CWS impact lines compared on your actual openings, style by style
Get your free estimateTherma-Tru Window Replacement: The Fort Worth Owner’s Guide
If you have a Therma-Tru window with a failed sash, broken glass, or a frame that no longer seals, we replace it with a Therma-Tru-compatible unit sized to your existing opening. Most Therma-Tru window replacements in Fort Worth run between $600 and $1,250 per window installed, depending on glass package and frame condition. We stock common Therma-Tru replacement hardware on our trucks, and we can typically have your new unit ordered and installed within one to two weeks if custom sizing is required.
Here’s how most Fort Worth homeowners discover the problem: a window that used to open with one hand now takes two, condensation has settled permanently between the panes, or a draft near the sill shows up every time a north wind pushes through Tarrant County. Sometimes the failure is sudden, like a cracked pane from a hail storm. More often it’s gradual, and by the time you notice, the seal has been compromised for a season or more.
This page covers exactly what we see in the field with Therma-Tru units, what replacement actually costs in Fort Worth, and how to tell whether you need a full sash swap or just new hardware. If you want a specific number for your window, call (682) 900-6694 and we’ll walk through it together.
One honest note before we go further: Lightwell Windows Fort Worth is an independent service provider. We are not affiliated with Therma-Tru, and we are not a factory-authorized service center. We work on Therma-Tru products because we trust the build quality and we know how to match replacement units correctly. If you’re still under a Therma-Tru warranty, call the manufacturer first. If that route has run out, we can likely help at a better price than replacing the whole window.
Which Therma-Tru Models This Applies To
Therma-Tru is known primarily for entry doors, but many Fort Worth homes built since the mid-2000s carry Therma-Tru vinyl and fiberglass windows, often installed alongside a Therma-Tru door as part of a whole-opening package. The window lines we see most often here are the Classic-Craft, Smooth-Star, and Fiber-Classic companion windows, all of which share similar sash hardware and glazing beads.
Here’s the compatibility gotcha most people miss: Therma-Tru window sashes are not universal across series. A sash from a Smooth-Star unit will not seat properly in a Fiber-Classic frame, even if the visible glass dimensions match within a quarter inch. We confirm the series by checking the corner gasket profile and the sash lock geometry, not just the etched glass code. If your window has an AAMA or NFRC label still attached, read us that number over the phone and we can usually identify the series before we even schedule a site visit.
On the OEM-versus-aftermarket question: for glass, we generally recommend staying with OEM or OEM-equivalent insulated glass units (IGUs), because Therma-Tru’s glazing channel tolerances are tight and the sealant bed is specific to their spacer profile. For hardware, like sash locks, pivot bars, and coil balances, quality aftermarket equivalents are often just as durable and cost 40% less than factory-listed parts. We’ll show you both options in writing before you decide.
Styles & brands we work with










Signs Your Therma-Tru Window Replacement Is Failing
- Condensation between the panes that never clears. This is the signature of a failed IG seal. The desiccant inside the spacer has saturated, and once that happens, the glass can’t be dried out. You’re looking at glass replacement, not repair.
- The sash tilts forward when you open it. Coil balances lose tension over time, and in the Fort Worth climate, dust and grime work into the balance channel. The sash will start to drift or slam shut, and the fix is a balance replacement, not a new window.
- A draft you can feel with your hand at the meeting rail. Worn weatherstripping or a warped sash lets air through the lock point. It’s most noticeable in January and July, and it costs you money every month the window stays like that.
- The window no longer locks. Therma-Tru sash locks are cam-style, and when the cam wears down or the keeper plate shifts, the window won’t pull tight. The security issue is obvious, and it won’t get better on its own.
- The sash is hard to raise or lower. Caked-on dirt in the jamb track, a failed pivot bar, or a misaligned shoe can all cause resistance. Forcing it usually breaks something else, so we’d rather you call once the window needs two hands to operate.
See the difference
Before
After
Before
AfterReplacement Cost & What’s Included
In Fort Worth, plan on $600 to $1,250 per window installed. The low end covers a single sash replacement with standard clear dual-pane glass and existing frame reuse. The high end covers a full frame replacement, a Low-E glass package, and work around a deteriorated opening. If your Therma-Tru window is an unusual size or you want argon-filled glazing with a warm-edge spacer, the price shifts accordingly.
Every quote we give breaks down parts and labor separately, in writing, before any work is scheduled. You’ll see the cost of the replacement unit, the cost of hardware if needed, and the cost of installation. That written price doesn’t change once we start, period. This is the Cedarwell Care Promise at work: no number surprises, no “while we were in there” additions.
What’s included with every replacement: removal of the old sash or frame, disposal, installation and shimming, interior and exterior caulking, and a cleanup that leaves your floors in the same condition we found them. The work is backed by our 365-Day Done Right Promise. If something isn’t right with the install, we come back and make it right. No argument, no countdown.
DIY or Call Us?
There are things worth checking yourself. Confirm the window is actually a Therma-Tru by looking for the manufacturer sticker on the frame edge. Check whether the glass itself is cracked or whether it’s just the outer seal that’s deteriorated. Take a photo of the spacer (the material between the two panes), because whether it’s aluminum or a warm-edge foam tells us a lot about the original glass package. Those three things take ten minutes and help us give you a tighter phone estimate.
Where DIY goes wrong is when the sash comes out of the frame. Vinyl windows are forgiving until they’re not: a pivot bar snaps, the jamb liner gets bent, or the glass slips out of the glazing channel when you’re leaning it against the wall. Then you’re replacing a sash plus the parts you damaged, and the savings vanish. If the work requires pulling the sash with the glass in it, that’s the line where we’d rather be the ones doing it. Keith Yamada has measured and installed frames along the edges of the TCU campus, where older bungalows make every window opening slightly different from the one next to it. We’d rather spend an extra twenty minutes measuring than send someone back twice.
If you’re on the fence, call (682) 900-6694. Describe what the window is doing, and we’ll tell you honestly whether it’s a hardware fix, a glass replacement, or a full unit swap. The assessment doesn’t obligate you to anything.
FAQs
A well-installed Therma-Tru window in the Fort Worth area typically lasts 15 to 25 years, though glass seals can fail in as few as 8 to 10 years under direct western exposure. Our North Texas summers put more thermal stress on IG seals than most climates, so south- and west-facing windows usually fail sooner. If your windows are over 12 years old and show fogging, the seal has run its course. Call (682) 900-6694 and we’ll tell you if the rest of the window is worth saving.
Yes, in many cases. Failed glass can be replaced as an insulated unit without swapping the whole window, sash hardware can be replaced, and weatherstripping can be renewed. The exception is a warped or cracked frame, which usually warrants a full replacement. We’ll always show you the repair price and the replace price side by side so you can decide with real numbers.
Once your replacement unit is on hand, a typical sash or glass swap takes one to two hours per window. A full frame replacement runs half a day per window, including interior and exterior trim work. We protect your floors with drop cloths and wear shoe covers inside, and we send you a photo of the cleanup before our crew leaves the driveway.
We stock the most common Therma-Tru hardware on our trucks, including cam locks, pivot bars, coil balances, and glazing bead for the current series. If your part needs to be ordered, most hardware from our supplier network arrives within three to five business days. Custom IGUs take a little longer because the glass is fabricated to your exact size. Alongside Therma-Tru, we also stock replacement hardware for PGT, CGI, and CWS windows, which covers a lot of the product installed around Tarrant County.
If you have a Therma-Tru window that’s fogged, drafty, or hard to operate, call (682) 900-6694 for a free estimate. A real person answers the phone, we’ll put the price in writing before any work begins, and the crew that shows up will treat your home the way they’d treat their own.
Written by Keith Yamada, Owner, Lightwell Windows Fort Worth at Lightwell Windows Fort Worth, serving Fort Worth and nearby areas.
Six Reasons Homeowners Choose Lightwell Windows Fort Worth
Laminated glass and reinforced frames hold up to wind-driven rain, hail and flying debris, so your openings stay sealed when the weather turns.
Low-E insulated impact glass from our manufacturer lines commonly cuts monthly cooling bills 20-30%.
Laminated impact glass shuts out up to 40% of outside noise - traffic, neighbors, weather.
Monitoring services run $30-90 a month. Laminated impact glass resists forced entry around the clock, with no subscription.
Tighter seals and insulated glass even out hot and cold rooms and stop the drafts at the frame.
A full impact package upgrades curb appeal, buyer confidence and appraised value in one project.