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

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

Therma-Tru window installation in Kendall typically runs $340-$780 per opening depending on frame condition, glazing specification, and whether the existing rough opening needs reframing. We stock Therma-Tru-compatible frames, sashes, and hardware across the Classic-Craft, Fiber-Classic, and Smooth-Star series, and most Kendall jobs we measure in the morning are ready for install scheduling within 48 hours. Most homeowners realize something’s wrong when they notice drafts around the frame edge, visible daylight between sash and jamb, or the window refusing to stay open on its own - all signs the installation has shifted, settled, or failed at the seal.

Call (786) 321-3319

Which Therma-Tru Models This Applies To

Therma-Tru labels its window products by series, not by individual part numbers on the frame itself. Look for a stamped metal tag on the top edge of the sash or a printed label inside the jamb pocket - you’ll see “Classic-Craft,” “Fiber-Classic,” or “Smooth-Star,” followed by a four-digit date code. The date code matters: pre-2019 Fiber-Classic units used a narrower 2-5/8″ frame depth that won’t accept current replacement sashes without jamb extension work. Post-2019 units shifted to 3-1/4″ nominal depth, which is what we carry on the truck.

We install OEM Therma-Tru frames and sashes where the opening permits, but we’ve also sourced quality aftermarket equivalents from CWS and PGT when the original series is discontinued or when the homeowner wants impact-rated upgrade without full-frame replacement. The decision point is usually the condition of the existing sub-sill: if it’s rotted or termite-damaged - common in Kendall’s older Pinecrest-adjacent ranch homes - a full-frame OEM replacement is the only call that makes sense. If the sub-sill is sound, a sash-pack or insert window from a compatible line saves labor and keeps the trim intact.

One compatibility gotcha we see regularly: Therma-Tru’s sliding patio door rollers from the 2016-2020 production run used a proprietary 1-1/4″ axle spacing that aftermarket rollers don’t match. We stock both specs on the truck, but we’ve learned to measure before we quote.

Signs Your Therma-Tru Window Installation Is Failing

• Visible gap at the sash-to-jamb reveal. The gap should be consistent to within 1/16″ top to bottom. When you see tapering - wider at the top, pinched at the bottom - the installation has racked, usually from foundation settlement or improper shimming at original install. In Kendall’s coral-rock substrate, we’ve found shims compressed or missing entirely on homes built during the 2004-2007 rush.
• Condensation between panes on insulated glass units. The seal has failed. Therma-Tru’s IGUs from that era carried a 20-year seal warranty, but the warranty covers the glass unit, not the labor to remove and reinstall it. We document the seal failure with photos, pull the sash, and order the replacement IGU to the exact sightline dimension - not the nominal frame size, which is how mismatches happen.
• Window falls closed when propped open. The balance system has failed. On single- and double-hung units, this means the coil spring or block-and-tackle is broken. These are under tension and can release suddenly. We don’t recommend homeowner removal - the sash is heavy and the spring is under load.
• Water staining on the interior sill after heavy rain. The flashing tape at the head jamb has separated, or the weep holes in the vinyl track are clogged with paint or debris. Kendall’s driving summer rains find every path. We clear the weeps, pull the trim to inspect the head flashing, and reseal with backer rod and silicone compatible with Therma-Tru’s frame material.
• Operation gets stiff, then grinds. The sill track is deformed or the sash rollers have flat-spotted. On horizontal sliders, this is usually debris in the track; on hung units, it’s often a tilt-latch that’s partially released and catching the jamb liner. We check both before assuming the frame is twisted.

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Replacement Cost & What’s Included

What drives the range: frame material (Smooth-Star vinyl is simpler to work with than Classic-Craft fiberglass), whether the interior trim can be saved, and whether we find rot when the old unit comes out. We don’t guess at this - Haven Clause 1 means you get the written price before we start, and that price comes from a measured survey we leave with you. If we open the wall and find something unexpected, we photograph it, show you, and write a revised scope before proceeding. No change orders on work already in progress.

The 365-Day Done Right Promise covers the installation, the sealants, and the operation. If the sash binds, the seal leaks, or the hardware fails in that window, we make it right. The manufacturer’s warranty on the product itself runs separately - Therma-Tru warranties vary by series, and we’ll note the specific coverage on your written scope.

DIY or Call Us?

There’s a short list of checks a Kendall homeowner can make safely: verify the weep holes are clear, confirm the window is fully locked (a partially engaged lock mimics a binding sash), and look for visible damage to the exterior caulking. Take photos of anything you find - we use them in our pre-site review.

What we don’t recommend: removing a hung sash with a failed balance, cutting out a fixed picture window, or attempting to reglaze an IGU yourself. The balance spring is under tension and can cause injury when released; the IGU is heavy and the seal repair requires a vacuum chamber and argon fill you don’t have. We’ve been called to jobs where a homeowner cracked the replacement glass trying to seat it dry, or where the frame went out of square because it wasn’t shimmed during install - and now the opening needs reframing too.

We carry Therma-Tru-compatible frames, sashes, balances, and hardware on our trucks. Measure once, document it, then cut - that’s how Sonia Raman trained the crew, and it’s why we dry-fit every unit before sealant touches glass. If you’re seeing any of the symptoms above, call (786) 321-3319 and we’ll schedule a measured survey. The written quote is yours to keep, whether you hire us or not.

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