Insert Replacement Windows — Pocket Install in the Old Frame
The frames are sound, the trim is worth keeping, and you want new windows without tearing into the walls. An insert slides into the old frame.
JMB Builders installs insert replacement windows across the Twin Cities metro. We measure your existing frames in person, order windows sized to fit inside them, remove the old sashes, stops and balances, insulate the weight pockets, set the new unit level in the pocket, seal it inside and out, and cap or trim the outside. Your interior casing stays. Priced per window, quoted from photos.
- Priced per window, windows supplied
- Interior casing stays in place
- In-home measure before anything is ordered
- Licensed MN contractor BC809005
An insert, also called a pocket install, puts a new window inside the old window's frame. The sashes, stops and balances come out; the frame, interior casing and exterior trim stay. It is faster and less disruptive than a full tear-out, and it keeps original woodwork that would be hard to match.
It only works if the old frame is sound and close to square. An insert set in a rotted or racked frame inherits every problem the old window had. We check each frame at the measure with a level and a probe, and if one fails, we tell you which openings need full frame instead.
What you supply
- Your choice of brand, color, glass package and grilles
- Clear access to each window inside
- Paint color for new stops or trim — Painting is quoted as a separate line — or leave it primed and caulked and paint it yourself.
What JMB supplies
- In-home measure of each frame, checked for square and rot
- The insert windows, ordered to fit the existing frames
- Removal and haul-away of old sashes, stops, balances and weights
- Insulation in weight pockets, low-expansion foam and backer rod
- New interior stops, and exterior aluminum capping or PVC trim over the old frame
- Photos of the finished windows in your job folder
How it is priced: per window
Quoted in writing from your photos within one business day. What moves the number:
- Window size, brand, frame material and glass package
- Exterior finish: aluminum capping, PVC trim, or reusing sound wood trim
- Weight pockets to insulate on old double hungs
- Frames that need minor sill repair before the insert goes in
- Second-story access
- How many windows in the job
Send photos of each window inside and out, and a close-up of the sill. Inserts depend on the old frame being solid.
How long it takes
Three to five insert windows in a day with capping. A whole house of inserts usually takes a few days.
How your project works
- 1
Send photos, get a written quote
Send three photos of the space and a sentence about what you want. You get a clear, itemized quote within one business day. We only come out to measure first when the job needs a tape measure — no pressure, no games.
- 2
Pick materials, or bring your own
We help you choose profiles and materials that fit the house and the budget, or match your existing millwork exactly — or you buy the door or trim yourself and we install it. Everything is confirmed before the crew is scheduled.
- 3
Clean, precise installation
The crew shows up on time, protects floors and furniture, and installs with tight joints and consistent reveals. Photos of the finished work go in your job folder.
- 4
Walkthrough and invoice
We walk the finished work with you. If anything is not right, we fix it before we call the job done. Then one invoice, paid by check or direct deposit — no card fees, no payment links.
Situations and options
Insert with aluminum capping
The old exterior wood frame and sill are wrapped in bent aluminum coil so there is no paint to keep up outside. The most common finish on an insert job.
Insert with PVC trim
Cellular PVC trim over the old frame outside. Thicker lines than coil, and it takes paint if you want a color.
Insert with new interior stops only
When the casing is original woodwork worth keeping, only the stops are replaced to hold the new window. The trim is not touched.
Insert Replacement Windows — Pocket Install in the Old Frame: questions, answered
What is an insert replacement window?
It is a new window sized to fit inside the frame of your existing window. The old sashes and parts come out, and the frame, interior casing and exterior trim stay. It is also called a pocket or retrofit install.
Do insert windows lose glass area?
Yes, a little. The new window's frame sits inside the old frame, so you lose about an inch or more on each side. On most double hungs it is hardly noticed; on small windows it can be.
When is an insert window a bad idea?
When the old frame or sill is rotted, badly out of square, or leaking water into the wall. An insert does not fix the opening; it relies on it. In those cases full frame replacement is the right call.
Do you keep my original interior trim with insert windows?
Yes. The interior casing stays and only the stops are replaced. If the new window leaves a gap to the casing, the gap is filled or covered cleanly, not caulked over.
What goes on the outside of an insert window?
Usually the old wood frame and sill are wrapped in aluminum coil or covered with PVC trim so there is no bare wood left to paint. The joint between the new window and the capping is sealed.
Are insert windows as energy efficient as full frame?
The window itself is the same. The difference is at the edge: an insert relies on the old frame being sealed to the wall. We insulate the weight pockets and foam the gaps, which takes care of most of it in a sound frame.
Recent JMB work, from our job log
59 installs recorded across 30 Twin Cities communities since Dec 2025. Window and door installs for homeowners and for the builders and dealers we sub for. Counts come straight from our job log; no customer names.
Get a written quote for this job
Three photos and a sentence is enough. You hear back within one business day. Or text the photos to 763-204-2099.
Related jobs we do
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Read morePage reviewed September 26, 2026 · JMB Builders LLC, MN license BC809005 · All windows pages
Where we work
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Based in Zimmerman, scheduling across the Twin Cities metro. Closest first: