Start with conditions, not a product
Efficiency ratings only hold up if flashing, sill work, and installation technique are done correctly.
Build a complete scope
- What is currently installed and how much life is left in it
- Whether the house is in the historic core or the subdivision ring
- Openings measured individually rather than taken from a builder plan
- Frame material and thermal break for a cold-winter climate
- Air sealing at the install, trim, disposal, and the warranty on labor
Naperville context
Window openings in Naperville-area homes reflect the era they were framed in: older homes near the historic district and early-20th-century additions often carry smaller, non-standard rough openings, while postwar ranch and split-level subdivisions standardized around wood double-hung sash that has since been replaced piecemeal over decades. DuPage County's building requirements and, for homes inside recognized historic areas, added review can affect what can be swapped in versus what needs a custom unit. Illinois' summer humidity and winter cold both put real demands on seal and frame performance regardless of a home's age.