Windows and siding in Madison County
5 places we cover, and the rules that apply in each.
Every place in Madison County enforces the same residential energy code, and that is not a coincidence or a courtesy — it is state law. The Illinois Energy Conservation Code sets the standard for the whole state, and no unit of local government, home rule or not, may regulate residential energy standards in a way that is either weaker or stronger than it. The Capital Development Board adopted the 2024 edition, in force since 30 November 2025.
What still changes city to city here is permits and contractor requirements, and those change a great deal. One village in this metro exempts siding and window replacement outright; a city ten minutes away deleted its entire exemption list.
62.2% of the housing in Madison County was built before 1980, and 14.7% before 1940 (17,440 of 118,942 units). That is the number that decides whether the federal lead rule is on your job, and on both of these trades it very often is: window replacement is never exempt from it at any size, and a whole-house re-side clears the exterior threshold immediately.
| Place | Permit to re-side? | Permit for a like-for-like window? | Adopted energy code | Window must meet |
|---|---|---|---|---|
| Alton | Yes | Yes | 2024 IECC, as amended by the Capital Development Board (Illinois Energy Conservation Code) - statewide, effective 11/30/2025 | — |
| Collinsville | Yes | Depends | Illinois Energy Conservation Code (statewide) | — |
| Edwardsville | Yes | Yes | Illinois Energy Conservation Code (rolling) | — |
| Glen Carbon | Not published | Not published | 2024 IECC, as amended by the Capital Development Board (Illinois Energy Conservation Code) - statewide, effective 11/30/2025 | — |
| Granite City | Depends | Depends | Illinois Energy Conservation Code (statewide) | None adopted |
Things worth knowing before you sign anything
Alton
Permits are filed through a third-party BS&A Online portal rather than the city's own site. The Building Permit Application is a free-text form with no work-type checkboxes, so what counts as permit work is decided at the counter. Fee schedule has no siding or window line at all.
Collinsville
The $500 exterior-work threshold is published as a guideline with the caveat 'although there are exceptions.' The city straddles the Madison/St. Clair county line. Roofing (but not siding or windows) triggers a state Illinois Roofing Contractor licence check on the application form.
Edwardsville
Edwardsville’s adopted climate design table prints a 114 mph wind speed and a 40-inch frost line — both a step above the Missouri side. Adopted codes are current 2021 I-Codes (IBC, IRC with amendments, IEBC, IFC, IMC, IFGC, IPMC) plus 2020 NEC - among the most current in this metro - yet the same page cites a 2018 state energy code.
Glen Carbon
'We've Gone Paperless! For your convenience, we've transitioned to an online permitting system' and 'Paper applications and applications submitted via email will no longer be accepted.' Everything goes through a Tyler EnerGov self-service portal (https://glencarbonil-energovpub.tylerhost.net/apps/selfservice#/applicationAssistant), which means a contractor must create a portal account before pulling any permit. The Village deletes several model-code permit exemptions (Sec. 105.2 paragraphs 1, 2, 3, 5 and 6) rather than adding to them - a signal that Glen Carbon permits more work than the model code would, though the deletion is written against the Building Code, not the Residential Code.
Granite City
Contractor business licence for general contractors is the strongest published Illinois-side differentiator in this metro after Belleville.
Windows or siding in Madison County?
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