The main frame stays.
A · Existing main frame retained. Its condition matters because it becomes the base for the replacement.
B · New unit fits inside. Ask for the resulting glass and operable-opening dimensions before ordering.
The main frame comes out.
A · Old main frame removed. The work reaches the opening in the wall; surrounding finishes may also need work.
B · New unit at the opening. Specify the air-sealing, flashing and finish-restoration scope in the proposal.
Technical basis: DOE / PNNL replacement checklist and Andersen’s replacement-method explanation.
An insert replacement fits within the existing main window frame. Full-frame replacement removes that frame and reaches the opening in the wall. Choose by the condition of what would remain and the work you need to accomplish. A method that preserves attractive trim can be useful, but preserving a frame does not resolve damage or leakage hidden around it.
Ask what stays and what comes out
Window terminology is not always consistent across proposals. Andersen describes inserts, flangeless full-frame replacements and flanged full-frame windows; the last type is often called “new construction” even when used in a remodel. Have the estimator mark retained and removed parts on a photo of your actual window. Andersen’s product and installation distinctions.
| Comparison | Insert approach | Full-frame approach |
|---|---|---|
| Existing main frame | Retained after suitability assessment | Removed |
| Rough-opening access | Ask what can actually be reached | Greater access, depending on adjacent work |
| Trim scope | Often a reason for choosing the approach; confirm details | Restoration needs must be explicitly priced |
| Finished glass and opening | Request actual resulting dimensions | Still depends on selected unit and opening |
| Water-management work | Ask which existing details remain | Specify new detail and wall integration |
| Unknown damage | Define inspection limits and response | Define repair allowances and approval process |
This table is a proposal comparison, not an installation specification. The wall, product instructions and project conditions determine the buildable detail.
Why retained-frame condition is a decision point
An insert relies on material that remains in place. Ask the installer how that material was assessed and what signs would change the recommendation. Record existing water history rather than assuming a newly finished exterior proves the concealed opening is dry and sound.
PNNL’s window replacement checklist identifies a key tradeoff: retaining the existing frame can leave the rough-opening air gap and flashing conditions unaddressed. Full-frame work offers a chance to address them, but the scope still needs to say so. DOE/PNNL replacement checklist.
Ask for a distinction between the air seal around the installed product and the work around the original frame. They are not automatically the same line item. A seller should be able to explain which junctions are accessible and how the proposed installation handles each.
Compare the finished opening before ordering
Request dimensioned information for the visible glass and operable opening in the proposed configuration. Do not compare only the exterior unit size. Ask how frame widths, meeting rails and grille patterns will align with adjacent windows and whether existing shades or shutters can be retained.
Use a room-specific review. A living-room picture window may be judged primarily on view and appearance; an operable bedroom unit needs separate confirmation of its required function. Ask the installer and responsible authority to review applicable safety and emergency-opening questions before choosing an operator or reducing an opening. This guide does not certify an individual window for code compliance.
Full-frame work needs a restoration plan
Full-frame is not a synonym for everything included. Ask whether casing, stools, drywall edges, exterior trim and paint are included, reused or supplied by others. If finishes cannot be matched exactly, discuss the boundary of the completed work before demolition begins.
PNNL’s full-frame guidance describes different approaches when surrounding siding remains versus when siding and the water-resistive barrier are also replaced. Existing wall construction therefore matters to the detail; one generic installation drawing does not resolve every project. PNNL complete window and frame replacement.
Request documentation of the proposed flashing and drainage approach and photos before the work is concealed. Also ask how the contractor will obtain approval for hidden repairs. A clear change procedure should distinguish the base scope from newly discovered damage, identify the proposed remedy and record price approval before extra work proceeds.
Compare two scopes, not two slogans
For an opening that could support either method, ask the same company or competing companies to explain the difference in finished result, included work and remaining uncertainty. A higher total may buy additional work you need, or features you do not value. A lower total may be appropriate, provided the scope addresses the actual condition and goal.
A useful decision note reads: “Retain this frame because the assessment found it suitable; confirm resulting glass dimensions and finish details before order.” Another might read: “Remove this frame to investigate documented recurring water entry; repair scope subject to photographed findings and written approval.” Both are more actionable than “premium install.”
Prepare your full-frame project scope, review the quote-comparison guide, or return to the complete Tulsa window guide. The project planner gives you a place to preserve the open questions for the estimator.