Illinois window replacement leads
Summit Leads supplies window replacement leads in Illinois with real-time ping/post delivery, exclusive by default, and ZIP code filters. Illinois moved its residential energy code to the 2024 IECC with amendments (DOE, checked October 7, 2026), and its housing stock is old, with a median build year of 1971.
- Founded in 2025
- 40+ national buyer and supply partners
- All U.S. states
- Exclusive by default
Illinois facts for window replacement lead buyers
| Fact | Value Source |
|---|---|
| Residential energy code | 2024 IECC with amendments, effective November 30, 2025 (DOE, checked October 7, 2026)Building Energy Codes Program: Illinois U.S. Department of Energy |
| IECC 2021 climate zones | Zone 5A in 58 counties and zone 4A in 44 (PNNL for DOE, 2021 county data)Guide to Determining Climate Zone by County: Building America and IECC 2021 Updates (PNNL-33270) Pacific Northwest National Laboratory for the U.S. Department of Energy |
| ENERGY STAR window climate zones | Spans more than one zone (map, August 2025)ENERGY STAR Windows, Doors and Skylights Climate Zone Map (August 2025) U.S. EPA ENERGY STAR |
| Median year structure built | 1971 (ACS 5-year 2020-2024)Table B25035, Median Year Structure Built: Illinois (ACS 5-Year 2020-2024) U.S. Census Bureau |
| Housing units built before 1980 | 63.5% (ACS 5-year 2020-2024, table B25034)Table B25034, Year Structure Built: Illinois (ACS 5-Year 2020-2024) U.S. Census Bureau |
| Housing units built 1939 or earlier | 1,104,684 (ACS 5-year 2020-2024, table B25034)Table B25034, Year Structure Built: Illinois (ACS 5-Year 2020-2024) U.S. Census Bureau |
| Median home value | $263,300 (ACS 5-year 2020-2024, table B25077)Table B25077, Median Value (Dollars): Illinois (ACS 5-Year 2020-2024) U.S. Census Bureau |
| Contractor licensing and insurance | No state license for general contractors; Home Repair and Remodeling Act insurance required (Attorney General, rev. July 2026)Home Repair and Construction: How to Choose a Contractor (rev. July 2026) Illinois Attorney General |
Last reviewed: October 7, 2026. A summary for education, not legal advice.
Illinois homes now fall under the 2024 IECC
This section is general information, not legal advice. It summarizes official sources as of October 7, 2026; check the current text of each rule before relying on it.
Illinois has moved to the 2024 edition of the IECC. The DOE Illinois status page (checked October 7, 2026) lists the 2024 IECC with amendments as the current residential code, effective November 30, 2025, with the same date for the commercial code. The page gives no adoption date. For window buyers, the edition matters because replacement windows in a permitted renovation are checked against the code in force at the time of the permit.
Northern and southern Illinois zones
Illinois is long from north to south, and its 102 counties divide between two IECC zones. DOE's guide PNNL-33270 (2021 county data) lists 58 counties in zone 5A and 44 in zone 4A. Both carry the A designation, which DOE uses for moist climates.
ENERGY STAR also splits the state. Its climate zone map (August 2025) shows Illinois in more than one window zone, and the zone for a given county or ZIP code comes from the ENERGY STAR zone finder. A buyer with crews in both halves of the state can keep the zone for each county in its territory list.
A large prewar housing stock
Illinois has more than a million homes built before 1940. Table B25034 (ACS 5-year 2020-2024) counts 1,104,684 units built in 1939 or earlier, and 63.5% of all units date from before 1980. The statewide median build year is 1971 in table B25035 (ACS 5-year 2020-2024).
The median owner-occupied value is $263,300, from table B25077 (ACS 5-year 2020-2024). Prewar houses often have nonstandard window openings, and buyers that quote by opening size can ask for the build year and window count on each lead.
Contractor rules for Illinois window work
This section is general information, not legal advice. It summarizes official sources as of October 7, 2026; check the current text of each rule before relying on it.
The Illinois Attorney General's guide Home Repair and Construction: How to Choose a Contractor (rev. July 2026) states that general contractors are not required to be licensed or certified by the state, though they may need a permit from the municipality where they work. The same guide tells homeowners to verify that a contractor has the public liability and property damage insurance required by the Home Repair and Remodeling Act.
The guide names roofers and plumbers as licensed trades and does not list a state license for window installers. The home solicitation cancellation rule and the state's other buyer rules are on leads in Illinois.
Illinois window buyers choose leads by
- Home age: a build year separates prewar houses from postwar ones in a state with a large share of both.
- ZIP code: territory follows the county zone split and the municipal permit offices a crew works with.
- Number of windows and scope: full replacement or a few units, which affects how the newer energy code applies.
- Homeowner status: the person requesting the quote owns the house.
Where buyers filter in Illinois
Two of the largest metro areas with Illinois counties cross a state line, so their figures below are for the whole metro area. The six areas come from the Census Bureau's July 1, 2025 estimates. Within any of them, or outside them, buyers pick the ZIP codes they want.
- Chicago-Naperville-Elgin, IL-IN: 9,434,123 (July 1, 2025 estimate, whole metro area)
- St. Louis, MO-IL: 2,814,421 (July 1, 2025 estimate, whole metro area)
- Peoria: 363,505 (July 1, 2025 estimate)
- Rockford: 337,242 (July 1, 2025 estimate)
- Champaign-Urbana: 239,979 (July 1, 2025 estimate)
- Springfield: 206,033 (July 1, 2025 estimate)
Source: Metropolitan and Micropolitan Statistical Area population estimates, Vintage 2025 (cbsa-est2025-alldata), U.S. Census Bureau.
Consent records for Illinois window replacement leads
An Illinois window lead comes with the TCPATCPAThe Telephone Consumer Protection Act, the federal law that governs telemarketing calls and texts, autodialers, prerecorded voice messages and the Do Not Call Registry. Glossary consent record captured when the homeowner asked for a quote. The state telemarketing laws table has the Illinois calling rules, and leads in Illinois brings the state's MVA and home improvement information together.
Illinois window replacement lead questions
When did Illinois start using the 2024 IECC for homes?
DOE lists the 2024 IECC with amendments as effective November 30, 2025 on its Illinois page (checked October 7, 2026). This is general information, not legal advice.
Does Illinois license window installers?
The Attorney General's contractor guide (rev. July 2026) says general contractors need no state license but may need a local permit. This is general information, not legal advice.
How many Illinois homes were built before 1940?
The Census Bureau counts 1,104,684 units built in 1939 or earlier in table B25034 (ACS 5-year 2020-2024).
Which IECC zones split Illinois?
Zones 5A and 4A, with 58 and 44 counties, in PNNL-33270 for DOE (2021 county data).
Request Illinois window replacement leads
Email us the Illinois ZIP codes you cover, your daily volume or caps and how you take delivery. ReturnReturnA buyer's request for credit on a lead that fails agreed standards, such as a disconnected number, a duplicate or a lead outside the filters. Glossary terms are agreed on the onboarding call, before you go live.
Start small, with no long-term commitment
- No long-term contract. Pause or stop at any time.
- No setup fee and no monthly fee. You pay only for leads delivered that match your filters.
- Start with a small test volume and scale when the numbers work.
- MVA and home improvement leads are exclusive by default: each lead is sold to one buyer.
- Return terms are agreed on the onboarding call, before you go live.
Or write to team@summitleads.ai. We reply by email.
Generating leads instead? Sell your leads