Model assumptions
The base per-window bands are assumed inputs: vinyl $450–$750, fiberglass $600–
Estimate your window replacement
Illustrative budgeting assumptions, not a verified local price survey. Obtain itemized written quotes before making a purchase decision.
| Line item | Range |
|---|
Inserts cost less but you inherit the old frame's problems. Rot repair is priced per affected window once the old frame is open.
Estimate your window replacement
Illustrative budgeting assumptions, not a verified local price survey. Obtain itemized written quotes before making a purchase decision.
| Line item | Range |
|---|
Inserts cost less but you inherit the old frame's problems. Rot repair is priced per affected window once the old frame is open.
Rot must not disappear from the budget
The affected count is capped at the number of windows in the job. Choosing inserts keeps a conversion reserve for affected conventional windows and a separate repair allowance. It does not establish that inserts are suitable. A bay or bow has a separate structural assembly assumption, and concealed damage can exceed any allowance.
Correction, October 25, 2026: suspected rot was previously ignored under insert installation. It now remains in the modeled cost. The wording also distinguishes the assumed bands from actual local quotes.
Compare scope before price
Record each opening's dimensions, frame and glass specification, insert or full-frame method, interior/exterior trim, disposal and who repairs hidden damage. Separate energy savings from replacement necessity: this tool does not model reduced heating bills or establish a payback.
The contractor scope worksheet helps normalize competing bids. FTC contractor guidance supports checking written estimates and credentials; it does not validate our scenario prices. For a complete cash budget, use the ownership comparison calculator.