How to Estimate Window Replacement Costs Per Unit and Per Opening
Window replacement pricing has two components that trip up estimators: the unit cost (window plus hardware) and the installation cost per opening (labor, trim, flashing, and disposal). Retrofit inserts are cheaper to install than full-frame replacements, but the choice depends on the condition of the existing frame, and that's a judgment call you make at every opening - not once for the whole project. A house with 15 windows might have 12 retrofit candidates and 3 that need full-frame replacement because the frames are rotten or out of square. Treating all 15 the same way produces the wrong number in both directions.
This guide explains how to build a per-opening cost structure, walk the insert-vs-full-frame decision, and account for the variables that push labor rates up - window type, floor level, and custom sizing. Use the BidFlow Window Replacement Cost Calculator to run per-opening and whole-project estimates before quoting.