Reviewed by Mario Garcia, General Manager at Windows Hawaii
When you get a window quote, one of the first questions is how the new windows go in. There are two ways to do it: a retrofit install, where the new window fits inside the old frame, or a full-frame install, where everything comes out down to the studs. Here is how they differ, what each costs, and how to tell which one your Oahu home needs.
What Are Retrofit Windows?
A retrofit window, also called an insert or pocket window, is built to fit inside your existing window frame. The installer removes the old sashes and glass, leaves the frame in place, and sets the new window into that opening. The interior trim and exterior wall usually stay untouched.
Because nothing structural is opened up, a retrofit install is faster, quieter and less messy. It works well when the existing frame is solid, square and dry.
What Is Full-Frame Replacement?
A full-frame install removes the entire old window, including the frame, down to the rough opening in the wall. The new window is installed with fresh flashing and weatherproofing, then the trim inside and out is finished around it.
It is more work, but it is the only way to fix what is hiding behind the old frame, like rot, termite damage or past leaks. It also lets you change the size or style of the opening.
Retrofit vs. Full-Frame at a Glance
| Factor | Retrofit (insert) | Full-frame |
|---|---|---|
| What gets removed | Old sashes and glass only | The whole window, frame and all |
| Typical cost per window (national) | $450 to $1,500 | $700 to $2,000+ |
| Install time | Faster, less disruption | Longer, more trim and finish work |
| Glass area | Slightly smaller, since the new unit sits inside the old frame | Same as the original opening, or larger |
| Fixes hidden damage | No | Yes, the opening is fully exposed |
| Can change size or style | No | Yes |
| Best when | The frame is solid, square and dry | The frame is damaged or you want a different window |
Cost ranges are from HomeGuide. The cost gap comes mostly from labor: full-frame work adds removal, flashing, and new trim or exterior patching around each opening.
When Retrofit Makes Sense
- The existing frames are not soft, rotted or cracked.
- Windows open and close without binding, which is a good sign the frames are still square.
- You are happy with the current window sizes and layout.
- You want the job done quickly with as little disturbance to finished walls as possible.
When Full-Frame Is the Better Call
- Rot or termite damage. Termites are a constant issue in Hawaii, and wood frames and sills are a favorite target. Putting a new window into a damaged frame just hides the problem.
- Signs of leaks. Stains under the sill, bubbling paint or soft drywall around a window mean water has been getting in.
- Out-of-square openings. Settling can rack a frame so windows stick or show uneven gaps.
- Changing the window. Going bigger, adding a bay window or converting a style usually needs the full opening.
- Replacing jalousies. Old jalousie frames vary a lot. Some can take a retrofit window, many need to come out completely. Our jalousie window guide covers what to expect.
This Old House gives the same basic rule: choose an insert when the frame is square, level and undamaged, and go full-frame when it is rotted, warped or out of square.
What Is Different About Oahu Homes
Older aluminum frames
Many island homes still have original aluminum windows. Aluminum frames do not rot, but salt air can corrode them and the tracks wear out. Whether a retrofit works depends on the condition of the frame and how it was fastened to the wall.
Single-wall construction
A lot of older Hawaii homes are single-wall construction, with no hollow wall cavity behind the window. That changes how a new window is attached and finished, so we check the wall type at every measurement instead of assuming.
Wind-driven rain
On the windward side especially, rain does not just fall, it blows sideways. Whichever method we use, the flashing and sealing around the window is what keeps that water out.
Does Retrofit Lower Energy Efficiency?
Not in any meaningful way when it is installed correctly. The new window brings the same glass package either way, including Low-E glass that blocks heat and UV. The main trade-off is a little less glass area, which can mean slightly less light and view.
How We Decide
During your free in-home measurement, we check every frame for soft spots, termite damage, signs of water and squareness. Many homes end up with a mix: retrofit where the frames are good, full-frame where they are not. We walk you through which method each window needs before any work starts.
To ballpark your project, try the calculator in our window replacement cost guide. It lets you pick retrofit or full-frame.
Frequently Asked Questions
Are retrofit windows cheaper?
Usually, yes. National ranges run about $450 to $1,500 per window for an insert install versus $700 to $2,000 or more for full-frame, according to HomeGuide.
Do retrofit windows look different?
The frame line is a little thicker because the new window sits inside the old frame. In most rooms it is hard to notice, but on small windows the smaller glass area can stand out more.
Can I mix retrofit and full-frame in one project?
Yes, and it is common. Each opening gets the method its frame calls for.
Is full-frame replacement worth the extra cost?
When there is damage, yes. It is the only way to find and fix rot, termite damage or leaks before they spread. When the frame is solid, a retrofit install gives you the same new window for less.
How do I find out which my home needs?
Book a free in-home estimate or call 808-671-0808. We inspect every frame and explain what we find.
