Therma-Tru Window Replacement Nationwide | Sightline Windows & Doors Kendall

Therma-Tru Window Replacement: The Kendall Owner’s Guide

We stock and install Therma-Tru-compatible window replacement units in Kendall, with typical installed pricing running $340 to $780 per opening depending on series, glazing package, and whether the frame is salvageable. Most Therma-Tru sash, frame, and hardware replacements are available same-day from our Kendall inventory, and we carry the full measurement and quote on one document - Haven Clause 1. Homeowners usually discover the failure when a sash won’t stay open, they feel air movement around a closed frame, or they spot fog between the glass that wasn’t there last season.

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Which Therma-Tru Models This Applies To

Therma-Tru’s window line breaks into distinct series, and the replacement part you need depends on which one is in your wall. The Classic-Craft and Fiber-Classic collections use pultruded fiberglass frames with proprietary corner keys that differ from the smooth-welded vinyl joints on the Vented Sidelight and Patio Door series. Check the spacer bar between the glass panes for an etched code, or the hinge-side jamb for a stamped date and series mark - we photograph both during our survey so you have a record.

The OEM-versus-aftermarket question for Therma-Tru is specific: their glazing packages use a dual-seal warm-edge spacer system that third-party shops rarely replicate correctly. We source factory-spec insulated glass units through verified distribution, but we also stock quality aftermarket sash kits for the vinyl line when the frame is sound and the homeowner wants the repair done this week, not next month. The gotcha is the 2017-2019 Fiber-Classic casement run, which used a discontinued hinge shoe profile - we’ve seen three Kendall homes in the Dadeland area where a generic hinge was forced in and tore the frame mounting point. We stock the correct retrofitted bracket for that exact year range.

Signs Your Therma-Tru Window Replacement Is Failing

• Fog or haze between glass panes that won’t wipe away. The thermoplastic spacer seal has failed, allowing moist Kendall air into the air gap. Once the desiccant saturates, the view stays cloudy and the insulating value drops to near zero - we measure the frame opening and order a replacement IGU sized to the original sightline.
• Sash drops or won’t stay open. The balance system - coil spring or block-and-tackle depending on series - has lost tension or the pivot bar has cracked. In Kendall’s salt-air environment, the metal components corrode faster than inland specs, and we’ve replaced balances on ten-year-old units that should have lasted twenty.
• Visible frame separation at the corners. The fusion-welded joint or mechanical corner key has failed, usually from thermal cycling stress or improper shim support during original install. This is structural; the frame is no longer square and the sash won’t seat properly.
• Air infiltration around the closed sash. The weatherstrip has compressed past recovery or the sill track is worn below the compression threshold. We check with a smoke pencil during survey - if the leak is at the meeting rail, it’s usually the interlock gasket; if it’s at the sill, the pile weatherstrip or the drainage path is compromised.
• Hardware operates roughly or not at all. The multipoint lock mechanism has gummed with debris or the shootbolt has bent from forcing a misaligned sash. Therma-Tru’s hardware is series-specific; the Classic-Craft multipoint uses a different backset and faceplate width than the vinyl line.

Before

After

Replacement Cost & What’s Included

What drives the range: the glazing package (single-pane tempered vs. impact-rated laminated), whether the frame needs re-flashing to the Kendall wind-load code, and accessibility - second-story openings with no balcony access add ladder time. Our quote is the invoice. Haven Clause 1 means the measured survey you keep and the written price match exactly. Every Therma-Tru replacement carries our 365-Day Done Right Promise and leaves a documented photo record of before, during, and after.

DIY or Call Us?

There’s a safe middle ground and a hard stop. You can verify the series mark, photograph the failure, and check the sash operation with the lock disengaged - that’s useful information that speeds our survey. What we don’t recommend: removing a fixed sash from a Therma-Tru frame without knowing the clip sequence, or attempting to reglaze an IGU yourself. The glass edges are sharp, the units are heavy, and an improperly bedded IGU will fail again in six months when Kendall’s summer humidity finds the gap.

We carry Therma-Tru-compatible sash, IGU, and hardware inventory on our Kendall trucks. Measure once, document it, then cut - that’s how we work, and it’s why we don’t charge twice for the same opening. Call (786) 321-3319 to schedule your free estimate. We’ll bring the measured survey, the written price, and the part if it’s a standard replacement.

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