A pocket or insert replacement drops a new window inside the old frame. It is faster, cheaper and less disruptive — and it shrinks the glass. In a bedroom, that can take a legal egress opening below the minimum.
An insert window sits inside the existing frame, so the new unit is smaller than the old one and you lose glass on every side. That is usually cosmetic — except in a sleeping room, where the opening has to give 5.7 square feet net clear, which is 821 square inches. Measure the opening you have before anyone quotes an insert. If the old window is already close to the minimum, an insert cannot legally replace it.
A full-frame replacement removes everything down to the rough opening — sashes, jambs, the old frame — so the new window is installed into the framing itself. The interior and exterior trim comes off, the opening is inspected, and it is flashed and insulated fresh.
An insert, also sold as a pocket replacement, removes only the sashes and leaves the existing frame in place, fitting a complete new window inside it. The trim usually stays. It is a much smaller job.
The trade is straightforward once stated plainly: the insert is faster and cheaper and leaves your trim alone, and in exchange you keep the old frame, you do not see what is behind it, and the glass gets smaller.
Roughly the thickness of the new frame on all four sides. The exact figure depends on the product, but it is visible — and the proportional loss is worst on small windows, which are often the ones in bedrooms.
For most windows this is an aesthetic question. On a sleeping-room window it is a compliance question, because the code does not care how big the window used to be. It cares about the net clear opening you can actually climb through.
When the resulting opening in a sleeping room, basement or habitable attic falls below the emergency escape minimum. That is a net clear opening of at least 5.7 square feet, at least 24 inches high and 20 inches wide, achieved by normal operation of the window from inside.
Saint Paul publishes the number in a form you can check yourself: 5.7 square feet is 821 square inches when you multiply the opening’s width by its height in inches. Measure the clear opening of your existing window, subtract what an insert frame would take on each side, and see whether the result still clears 821.
A lot of older Minnesota bedroom windows are already at or near the minimum. An insert in one of those is not a cheaper option, it is a non-compliant one — and replacing a window is permitted work, so an inspector may well see it.
City of Saint Paul, Emergency Escape and Rescue Openings, Section R310 of the 2020 Minnesota Residential Code: “5.7 Square Feet Minimum Net Clear Opening Area […] 24″ Minimum Net Clear Opening Height […] 20″ Minimum Net Clear Opening Width. Note: 5.7 Square Feet = 821 Square Inches when multiplying width times height of the opening in inches.” Source: City of Saint Paul, Emergency Escape and Rescue Openings
When the existing frame is sound, square and dry, the trim is worth keeping, and the opening is nowhere near an egress minimum. Those conditions are common, and in that case an insert is good value and we will install one.
The honest caveat is that “sound, square and dry” is a judgement made from outside the frame. Nobody can see rot in the sill or a failed flashing detail without opening it up, which an insert does not do.
So the question to ask is not which method is better in general. It is: what is the condition of the frame you are proposing to keep, and how do you know?
When there is rot or water damage in the frame or sill, when the opening has to grow to meet egress, when the original flashing is suspect, or when the frame is out of square enough that an insert would never seal properly.
Also when the window is being replaced as part of a re-side. The siding is off and the water-resistive barrier and flashing are being inspected anyway — that is the one moment a window can be properly integrated into the wall’s drainage plane at no extra disruption. Fitting an insert then, and leaving the old frame and its old flashing inside a brand-new wall assembly, is a missed opportunity you cannot get back.
Which method, named in words rather than implied by price. The net clear opening dimensions of the result for any sleeping room. Whether the price includes interior and exterior trim, because full-frame disturbs both. And whether the permit is included.
If two window quotes are far apart, this is usually why, and it is not a like-for-like comparison. Ask both which method they are quoting before you compare the numbers.
This page quotes Minnesota statutes and the adopted Minnesota building code and links to the official text of each so you can read it yourself. It is general information from a licensed contractor, not legal advice, and it is not a substitute for reading your own policy. Statutes and codes are amended; the linked sources are authoritative, this page is not. Last reviewed 2026-10-27.
Straight answers to the questions Minnesota homeowners ask before they call anyone.
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Read the FAQ →We’ll walk it, photograph it, and give you a written scope that says exactly what is required and why. Retail or insurance.
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