Therma-Tru Window Replacement Nationwide | Sightline Windows & Doors Lighthouse Point

Therma-Tru Window Replacement: The Lighthouse Point Owner’s Guide

Therma-Tru window replacement in Lighthouse Point typically runs $340-$780 per opening installed, depending on the series, glazing package, and whether the original frame is preserved or replaced. We stock Therma-Tru-compatible sashes, balances, and hardware for same-day repair on most configurations, and we carry full replacement units for the Classic-Craft, Fiber-Classic, and Smooth-Star lines in our Lighthouse Point warehouse. Most homeowners discover a problem when the sash won’t stay open, condensation appears between glass lites, or the lock no longer draws the sash tight against the weatherstrip.

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Which Therma-Tru Models This Applies To

Therma-Tru windows are less widely distributed in South Florida than their entry doors, which means parts compatibility is narrower than with PGT or CGI. We work with the Classic-Craft and Fiber-Classic series most commonly found in Lighthouse Point homes built between 2015 and 2022, plus the Smooth-Star line used in several canal-front developments near the Lighthouse Point Marina. The critical identifier is the etched code in the glass corner: it contains the manufacturing date, series designation, and insulating glass unit (IGU) specification. Without that code, we’re guessing at the glazing thickness and balance weight.

OEM sashes from Therma-Tru carry the exact profile match but lead times run 4-6 weeks. We stock quality aftermarket equivalents built to the same dimensional tolerances, with the same Low-E coating and argon fill, that install without modification. The trade-off is warranty length: OEM carries a 20-year glass seal warranty, while our aftermarket units carry 10 years. For a Lighthouse Point home facing salt air across the Intracoastal, we typically recommend OEM if the window is under 10 years old and aftermarket if the frame itself is showing wear.

Signs Your Therma-Tru Window Replacement Is Failing

• The sash drops or won’t stay open. This is almost always a failed coil balance or broken block-and-tackle assembly. In Therma-Tru double-hungs, the balance system is concealed in the jamb liner, and once the spring tension releases, the sash becomes a dead weight. We see this most often on south-facing windows in Lighthouse Point where daily heat cycling fatigues the metal.
• Fog or condensation between the glass panes. The insulating glass unit seal has failed, allowing moist Florida air into the airspace. Once the desiccant saturates, the fog becomes permanent. Therma-Tru IGUs use a dual-seal system, but the primary PIB seal can degrade faster in coastal humidity.
• Air infiltration around the sash even when locked. The weatherstrip compression set has permanently flattened, or the sash bowed slightly from thermal stress. Therma-Tru’s bulb-style weatherstrip is proprietary in profile, so generic replacement rarely seals correctly.
• Cracked or delaminating frame at the corners. The composite or fiberglass frame has absorbed moisture at a miter joint, or the reinforcement plate inside has corroded and expanded. This is structural; a sash replacement won’t solve it.
• Lock won’t engage or draws the sash crooked. The keep has shifted, the cam is worn, or the frame itself has racked out of square. On Therma-Tru units, the multi-point lock system depends on precise frame geometry; forcing the lock will strip the mechanism.

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Replacement Cost & What’s Included

The range reflects three variables: whether we preserve the existing frame and trim, the glazing specification (clear vs. Low-E vs. impact-rated), and the finish - painted, stained, or bare fiberglass requiring site finishing. Every quote we write in Lighthouse Point includes the measured survey you keep, the written scope with line-item pricing, removal and disposal of the old unit, installation per manufacturer spec, and the documented photo record. Our 365-Day Done Right Promise covers the installation; the sash itself carries the manufacturer’s glass seal warranty. We pull permits when required by Lighthouse Point building code, which applies to any impact-rated replacement in a designated wind-borne debris region.

DIY or Call Us?

An owner can safely check three things: whether the lock engages fully, whether the weatherstrip is visibly torn or flattened, and whether the glass code is legible. Do not attempt to remove a Therma-Tru sash without understanding the balance system; the coil spring stores significant tension and can release unpredictably. We have replaced sashes where the homeowner bent the jamb liner trying to force the sash past a stuck balance, turning a $400 repair into a $1,100 frame replacement.

Measure twice, write it down, then we talk price. That’s how Sonia Raman has handled every Lighthouse Point job since 2012, and it’s why our measured survey and your written quote are the same document. If you’re holding a competitor’s estimate, we offer a free second opinion - bring us the paperwork and we’ll review the specs against what your opening actually requires. Call (754) 600-8907 to schedule your free estimate.

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