Variable one: what is left of the sill and lower jambs
Everything else on this page is a tiebreaker. This one decides outright. A pocket unit is fastened through its jambs into the old frame, so the old frame has to be structurally sound wood, not something that used to be.
Push an awl into the sill at both corners and the middle and up each jamb six inches. Hard wood stops the point. Wood that accepts a quarter inch under thumb pressure will not hold a screw and will keep decaying behind whatever you put in front of it. On an Indiana house, start on the west and southwest walls, because that is the side storm-season rain arrives from and those openings run years ahead of the rest in failure.
Two refinements make the test worth trusting. Reach the underside of the sill from outside as well, since water collects in that corner and rot commonly starts there while the painted top face still looks perfect. And never judge a wide opening on one probe: the centre of a sill is often hard while both ends are gone, because the exposed end grain is what drinks.
Variable two: what the existing frame is made of
Old-growth wood
Pre-1940 jambs are deep, dense and often still excellent. They give an insert something genuinely solid to sit in, and the frame depth means the glass loss is proportionally smaller than it sounds. This is the material that makes pocket replacement a good answer rather than a cheap one.
Aluminum, and thin hollow vinyl
Both are effectively disqualifying. Aluminum stays in the wall as a cold bridge, so the frame frosts and the sill sweats regardless of the glass you buy. Hollow vinyl from the 1980s and 1990s has no solid jamb to fasten to and is already fat, so the daylight loss is severe. In both cases the original flashing is hidden and decades old, which is a second reason to take the whole thing out.
Variable four: trim on both faces of the wall
A tear-out destroys the interior casing, stool and apron and the exterior brickmould. If that trim is flat pine from 1985, replacing it is cheap and nobody mourns it. If it is quarter-sawn oak in a bungalow, or it runs into plaster that will let go at the corners, the trim is worth more than the two inches of glass you would gain.
What you cannot buy again
Quarter-sawn oak casing, plaster returns and jambs deep enough to carry a window without packing are not things a lumberyard will sell you in 2026. Where an opening has them and the wood underneath is sound, an insert protects them and a tear-out spends them for two inches of glass.
What you will happily replace
Flat pine casing, mitred colonial trim out of a 1990s tract build and aluminum-wrapped exterior trim are all cheap and quick to redo. When the trim falls in that category it stops being part of the argument, and the condition of the sill decides on its own.
Look at the exterior side as well. New brickmould next to sixty-year-old painted trim reads as a patch until it is painted out, so a partial tear-out on one elevation usually comes with a painting job attached.
Variable five: what else is coming off the Brookstone house
Timing changes the arithmetic more than any other single factor. Most of the $250 to $600 an opening that full-frame costs over an insert in 2026 is exterior labour and trim. If siding, wrap or exterior trim is coming off anyway in the next twelve months, that cost is already being paid, and doing the windows in the same sequence gets you flashing, a sill pan, full glass and any framing repair for a small fraction of the usual gap.
The reverse also holds. If the exterior was redone three years ago and is in good condition, cutting into it to gain a couple of inches of glass is an expensive way to undo recent work.
Variable six: openings, budget and how long you are staying
The multiplier nobody does in their head
The per-opening gap sounds small and then gets multiplied. On six openings the difference between methods is around $1,500 to $3,600. On eighteen openings the same choice is $4,500 to $10,800, which is a different conversation entirely and often the reason a whole-house project stalls.
Time horizon matters alongside it. If you are selling within two or three years, the visible upgrade does most of the work and the hidden flashing does not show up on a listing. If this is the house you are staying in, the tear-out on the weather side is the part you will be glad about in fifteen years, because it is the part that determines whether the wall stays dry.
How the variables usually stack up in Brookstone
Run all six across a real house and the pattern is consistent. A typical older home here ends up with two to five full-frame openings, almost always on the west and southwest walls where the sills are soft and the interior casing is stained, and inserts everywhere else where the wood is hard, the opening is square and the trim is worth keeping.
That mixed order usually prices within a few hundred dollars of the all-insert plan and thousands under the all-tear-out plan, while actually repairing the part of the house that is wet. If you defer instead, understand what you are deferring: a sill that could be cut back and scarfed this year generally cannot be next year, because freeze and thaw work water into the split end grain all winter and widen it every cycle.
Trade-offs no brochure puts in front of Brookstone homeowners
| Factor | Pocket insert | Full-frame |
|---|---|---|
| Time per opening | 45 to 90 minutes | 2 to 4 hours |
| Glass area | Loses about 2 to 2.5 in each way | Keeps the original size |
| Flashing and sill pan | Inherited, unseen | New, inspectable |
| Interior trim | Untouched | Replaced and repainted |
| Hidden rot | Stays hidden | Found and repaired |
| Best season here | Any month | Spring through late fall |
One line in that table is worth reading twice. An insert cannot be warranted against water intrusion in any meaningful way, because the drainage path was never exposed. A careful contractor will tell you that rather than promise otherwise.
Variable three: how much daylight the room can spare
An insert typically costs about an inch to an inch and a quarter per side, so roughly two to two and a half inches off the width and the height. Whether that matters depends entirely on the room, not on the window.
The egress line you cannot cross
Bedrooms and basement sleeping rooms have to keep a minimum net clear escape opening, generally in the region of 5.7 square feet above grade, with minimum clear height and width and a limit on sill height above the finished floor. Older openings often clear it by inches. Losing two and a half inches in both directions can drop an opening under the line, and fixing that afterward means cutting the wall and setting a header. Confirm the exact figures with your local building department before the order is placed.