Get the details down first
Note where you're seeing the issue, when it started, whether it tracks with weather, and what's changed over time. Rough measurements and a handful of photos give the first conversation more to work with.
Read the local context
Which era a Champaign house belongs to decides this job, and the city's history sorts them cleanly. The neighborhoods dating to the railroad town and its 1861 charter hold original wood sash that is frequently repairable, in openings that are rarely standard sizes and with paint layers that in housing of that age may be lead-bearing -- all of which can change the recommendation before a replacement is priced. The long expansion that followed the University of Illinois brought aluminum and early insulated units where the frame rather than the glass is the weak point. The climate then sets the specification: real winters here make frame material, thermal break and the air sealing at the installation more consequential than any glass coating.
Ask what gets covered up
A written scope should explain the preparation and verification that will no longer be visible at completion, not just the finished appearance.
Line the scopes up side by side
Look at how each proposal covers protection of finishes, access logistics, materials, permits, testing, cleanup, restoration, exclusions, warranty length, and change-order pricing.
What official local sources add
Candidly, this framework has almost no bearing on window replacement. The stormwater-connection permit concerns drains tied into the municipal system; land-disturbing permitting concerns ground disturbance; the coordination with Champaign County, Urbana, the University and Savoy concerns which authority reviews site work. A window touches none of them. Your permit is a building permit, and which office issues it depends on the address. What actually governs the outcome is physical — whether openings are square, what the framing is doing, and how the installation is flashed.
Sources were reviewed 2026-07-26. Floodplain mapping near the Boneyard and other local waterways, historic-district rules, and permit requirements are specific to each parcel — confirm current details with the City of Champaign or Champaign County before authorizing work.