A Lightwell company - serving Jacksonville, FL

Therma-Tru Window Replacement Nationwide

Single hungSingle hung
Double hungDouble hung
Horizontal rollerHorizontal roller
CasementCasement
Bay & bowBay & bow
Sliding glass doorsSliding glass doors
Entry doorsEntry doors
Impact garage doorsImpact garage doors
PGTPGT
CGICGI
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Therma-Tru Window Replacement: The Jacksonville Owner’s Guide

We stock and install Therma-Tru-compatible window replacements throughout Jacksonville, with most single-window replacement jobs running between $450 and $1,200 per opening depending on size, glass package, and frame condition. Most homeowners discover they need a replacement when the sash won’t stay up, the seal has fogged between the glass panes, or the frame has started to bind against the Florida humidity. You’ll typically know something is wrong before you can name it: a draft where there wasn’t one, condensation that won’t wipe away, or a crank that’s suddenly harder to turn than it was last spring.

Call (904) 914-3691

If a Therma-Tru window in your Jacksonville home has reached the point where parts have failed, this page covers what fits, what it costs, and how we handle the swap from first measurement to final cleanup. We’re an independent Jacksonville-based contractor, not affiliated with Therma-Tru, which means our recommendation is based on what your opening actually needs rather than what a single manufacturer wants to sell.

Which Therma-Tru Models This Applies To

Therma-Tru has built its reputation on entry doors, but their window lines appear most often in Florida homes as replacement units in existing openings. The compatibility question that matters most is not “which Therma-Tru model do I have” but “which Therma-Tru window series is in my opening right now.” In Jacksonville, we most often see the Therma-Tru Classic-Craft and Smooth-Star lines paired with matching transoms and sidelites, and the window units themselves are frequently custom-sized rather than stock dimensions.

That custom sizing is the gotcha worth knowing: Therma-Tru windows are commonly made to order for the specific rough opening, which means the replacement needs to be measured to the sixteenth of an inch, not ordered from a generic size chart. We measure the interior frame width and height, check the jamb depth, and photograph the corner joints and glazing bead profile so we can match the replacement to the original installation rather than guessing. For most Jacksonville homeowners, a quality aftermarket equivalent from our partner brands (PGT, CGI, CWS) delivers equal or better performance at a lower installed price than an OEM Therma-Tru replacement. We’ll show you both options and let you decide.

Explore

Styles & brands we work with

Single hung
Single hung
Double hung
Double hung
Horizontal roller
Horizontal roller
Casement
Casement
Bay & bow
Bay & bow
Sliding glass doors
Sliding glass doors
Entry doors
Entry doors
Impact garage doors
Impact garage doors
PGT
PGT
CGI
CGI

Signs Your Therma-Tru Window Replacement Is Failing

  • Fogging or condensation between the glass panes. This is a failed insulated glass unit seal, and in Jacksonville’s humidity it accelerates once the desiccant inside the spacer bar is saturated. No amount of wiping fixes it because the moisture is trapped inside the sealed unit. Replacement glass or a full sash swap is the reliable fix.
  • Drafts or visible daylight around the sash edges. Weatherstripping compresses over time, and on Florida homes near the St. Johns River or Atlantic coast, salt air eats at the seal edges faster than inland. The frame may still look fine while the air-seal is gone.
  • Difficulty cranking or sliding. Cassette cranks, hinges, and rollers wear out, especially on casement and slider styles. If the operator is grinding or the sash drags, the hardware has usually reached the end of its service life. Forcing it only bends the frame further.
  • Soft or discolored wood at the interior sill or jambs. Jacksonville’s afternoon thunderstorms and Florida’s six-month humid season put constant moisture pressure on window frames. Once wood begins to darken or feel spongy, water has been intruding for a while, and the structural frame needs addressing, not just the sash.
  • Persistent sticking that worsens with temperature swings. Vinyl and composite frames expand and contract in Jacksonville’s heat, and when a window that used to open easily now takes two hands, the frame geometry has shifted. Often the root cause is an installation issue or settling, and a properly measured replacement corrects it.
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Complete Upgrade

Replacement Cost & What’s Included

For Jacksonville homeowners, here’s the honest pricing picture before you call anyone:

Scope Typical Installed Price Range
Single window inserted into existing frame $450 – $850
Full-frame replacement (frame and sash) $700 – $1,200
Flashing, trim, and sill repair (as needed) $150 – $400
Matching transom or sidelite unit $350 – $700

What moves the price: the opening size, whether we’re replacing the glass and sash inside the existing frame or doing a full-frame replacement, the glass package you choose, and what we find when the old unit comes out. On older Jacksonville bungalows, especially in Avondale and Riverside, we sometimes uncover rot in the rough opening that wasn’t visible until the trim came off. That’s exactly why we give you a written line-item price before anything is touched, and why our price includes the labor to disconnect, set, level, insulate, and trim out the replacement properly. The 365-Day Done Right Promise and the Cedarwell Care Promise sit behind every one of these jobs. If the finished work isn’t right, we make it right.

DIY or Call Us?

Some things you can absolutely check yourself: wipe down the tracks and check for loose weatherstripping, tighten visible hinge screws, and note whether the failure is in the moving hardware or the fixed frame. But when a Therma-Tru unit has a failed insulated glass seal, a warped frame, or water intrusion at the rough opening, this is not a weekend project. The glass units are heavy, the custom sizes rarely match anything stocked at a Jacksonville big-box store, and putting a replacement into a compromised opening without addressing the water path means you’ll be doing the same job again in two years. We have the right lifting equipment, the right flashing materials, and the right trim experience to make the new unit look like it was always part of the house. Call (904) 914-3691 and we’ll walk through what we saw, what we’d recommend, and what it will cost in writing before we touch a single screw.

FAQs

Why Impact

Six Reasons Homeowners Choose Lightwell Windows Jacksonville

Hurricane Protection

Impact systems engineered to design pressures up to +/-100, matched to your wind zone - your openings hold when the storm arrives.

Energy Savings

Low-E insulated impact glass from our manufacturer lines commonly cuts monthly cooling bills 20-30%.

Noise Reduction

Laminated impact glass shuts out up to 40% of outside noise - traffic, neighbors, weather.

Burglar Resistant

Monitoring services run $30-90 a month. Laminated impact glass resists forced entry around the clock, with no subscription.

Insurance Savings

Florida homeowners average around 25% savings on the windstorm portion of their policy after protecting every opening - some homes qualify for more.

Property Value

A full impact package upgrades curb appeal, buyer confidence and appraised value in one project.

Other Services

Other Lightwell Windows Jacksonville Services

Reviews

What Neighbors Say About Lightwell Windows Jacksonville

★★★★★

"New patio slider. Clean install, they protected the floor and hauled off the old door. Quiet, polite crew that worked around my work calls without complaint."

AAndre Bellamy
★★★★★

"Quiet, considerate install of several windows. They cleaned the glass and the sills and vacuumed every room. You'd never know a crew had been through. House is quieter and brighter."

BBrent Sakamoto
★★★★★

"They replaced a big foggy picture window. Careful with the furniture, laid down protection, and left no mess at all. Calm and respectful crew, and the view is clear again."

TTeresa Okafor
★★★★★

"Replaced drafty old windows and a back door. The crew was gentle around my mother's antiques, protected everything, and cleaned up beautifully. Home feels warmer and calmer already."

WWalter Prim
★★★★

"Lovely windows and a tidy install. One window came in a couple weeks late from the factory, so that opening finished after the others. They kept me posted and the rest was spotless."

MMia Donnelly
★★★★★

"Front door replacement. The installers were careful, clean, and gentle, took their shoes off inside and swept the entry when done. The door seals perfectly and looks beautiful."

HHollis Wyatt
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