Therma-Tru Window Replacement Nationwide

Therma-Tru Window Replacement: The San Antonio Owner’s Guide

Therma-Tru window replacement in San Antonio typically runs $420 to $1,150 per window installed, depending on the model, glass package, and whether the frame itself needs work. We stock common Therma-Tru-compatible sashes, balance systems, and sealed glass units on our trucks, so most San Antonio jobs wrap up in a single visit. What usually brings homeowners to this page is a window that won’t stay up, has fogged glass, or suddenly lets in a draft that wasn’t there last winter.

Call (361) 348-8929

Therma-Tru built its name on entry doors, but their window lines, especially the sliding and single-hung units paired with those doors in newer San Antonio builds, have a specific set of failure points we see repeatedly across the city. The good news: almost all of them are repairable or replaceable without tearing out the surrounding wall.

Key Takeaways:

• Installed replacement pricing: $420 – $1,150 per window in San Antonio
• Most Therma-Tru window swaps are single-visit jobs
• We carry OEM Therma-Tru parts plus quality aftermarket equivalents
• Written price before any work starts, backed by the 365-Day Done Right Promise

Which Therma-Tru Models This Applies To

Therma-Tru’s window lineup includes the Classic-Craft, Fiber-Classic, and Smooth-Star series, along with the sliding patio door companion windows and the casement and picture units that show up in many San Antonio homes built after 2010. Each series uses slightly different hardware and glass dimensions, and that’s where we see owners get frustrated trying to order a “Therma-Tru replacement window” generically online.

Here’s the compatibility gotcha: a Therma-Tru Classic-Craft single-hung sash will not swap into a Smooth-Star frame. The balance shoe channels differ by about 3/16 of an inch, and the tilt-latch spacing doesn’t line up. If you’re not sure which series you have, look for the etched corner mark on the glass or the white serial label on the top of the sash rail. If neither is there, measure the visible glass height and width to the nearest 1/16 inch and call us. We’ll identify it before we quote it.

On the OEM versus aftermarket question: for glass units, OEM Therma-Tru or a matching low-E equivalent from a quality glass fabricator both work well. For hardware like balances, tilt latches, and weatherstripping, we often use the OEM part because the tolerances on Therma-Tru’s channels are tight. Spending a few extra dollars on the right part saves you a second service call.

Signs Your Therma-Tru Window Replacement Is Failing

• Fog or condensation trapped between the glass panes. The sealed unit’s desiccant is saturated and the inert gas has escaped. This means the insulated glass unit, or IGU, has failed and needs replacement. You can’t wipe it away because the moisture is inside.
• The sash won’t stay up, or it slams shut. The constant-force or block-and-tackle balance system has worn out. In San Antonio’s heat, the nylon bearings inside these balances dry out and crack faster than in milder climates.
• A draft you can feel with your hand around the sash perimeter. The weatherstripping has compressed or the sash has warped slightly. Therma-Tru’s compression bulb seals lose their rebound after years of triple-digit summers.
• Hard cranking or a casement window that won’t seal tight at the corners. The operator gear has stripped teeth, or the hinge arms have sagged. On Therma-Tru casements, we frequently replace the operator and hinge set as a pair because they wear together.
• Visible cracks in the frame or sash corners. Fiberglass and composite materials can develop stress cracks, particularly on west-facing San Antonio walls where afternoon sun pounds the frame for six months straight.

Replacement Cost & What’s Included

Here’s the honest dollar range we quote in San Antonio:

• Sealed glass unit replacement (IGU only): $280 – $520 per window installed
• Balance system replacement (both sides, single sash): $160 – $290 per window installed
• Full sash replacement with glass: $420 – $780 per window installed
• Complete window unit replacement (frame and all): $800 – $1,150 per window installed

What drives the range: window size, glass package (standard low-E versus a triple-pane or impact-rated unit), and whether the existing frame has hidden rot or water damage that needs repair before the new part goes in. Every quote is written down and delivered before any work starts. No change orders, no surprise line items on the invoice. The labor and the replacement part both carry our written guarantee, and if the repair fails within the covered period, the second visit is free. That’s the 365-Day Done Right Promise, and it’s stamped on every job we do in San Antonio.

DIY or Call Us?

You can safely check which series you have, take measurements of the visible glass, and take clear photos of the worn hardware or fogged glass. That actually speeds up the quote when you call. What we don’t recommend is pulling a Therma-Tru sash out of the frame yourself. The tilt-latch mechanism on these units is designed to release only at precise angles, and forcing it bends the latch pins. On casement windows, the operator arm is under spring tension, and removing it without the right technique can send the arm into the glass. Also, capping and sealing the exterior correctly is what prevents the next leak, and that’s the part that’s easy to get wrong on a San Antonio afternoon when the direct sun makes sealant set faster than you can tool it. We handle the removal, the part match, and the re-seal in one trip, and you know the price before we touch it. Call (361) 348-8929 and we’ll talk through what you’re seeing.

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