What the site adds
Finished basements, older panels, mature landscaping, and clay-soil grading can all add time before installation starts.
What the scope should spell out
Panel upgrades, transfer equipment, pad materials, and finish work belong in writing, not assumed.
Permits and outside expertise
DuPage County stormwater rules and municipal permitting can pull in extra review or an additional trade on larger systems. Confirm current requirements with the provider and the city.
Not a bid
A range on a screen is not a bid. Get a written number tied to your actual property.