Start with conditions, not a product
A full system swap should account for DuPage County's permitting rules, the home's existing duct routing, and its actual load—not just a like-for-like box replacement.
Build a complete scope
- The actual cause, confirmed, not assumed
- How the crew protects finishes and floors during the work
- Material compatibility with existing ductwork or piping
- Permit filings, testing, and cleanup
- Warranty terms and what counts as a change order
Naperville context
Naperville's housing stock spans a wide range of eras, from the brick core near the original 1831 settlement through the ranch and split-level subdivisions of the postwar decades to large newer-construction homes on the city's edges, and each era carries different duct routing, insulation levels, and electrical capacity. Illinois' climate swings from humid summer heat to sustained winter cold, so equipment sized for one era's envelope often struggles in either direction. DuPage County's permitting process for mechanical work adds another planning step that varies with a home's age and prior renovation history.