Insulation and window money in Naperville
The city pays through your electric bill. Nicor pays after you apply with proof of work.
City attic insulation
The 2026 rule was $1 a square foot up to $2,500, to R-49, with air sealing. No reopening date is stated.
City window replacement
The 2026 rule was $250 per window up to $2,500, for single-pane windows with a U-factor of 0.30 or lower.
Nicor Gas air sealing
Per home, with at least 200 CFM of air leakage removed. CFM is a measure of how much air flows through leaks.
Nicor Gas attic insulation
After air sealing, old insulation at R-20 or less, final R-49 or more.
Nicor Gas windows
High performance windows up to $3,000, and storm inserts $100 each up to $1,000.
State weatherization
For households at or below 200% of the federal poverty level.
The city's rules said you had to give at least $5 a month to its Renewable Energy Program for five years to qualify for attic and window money.
What happened to the city money
Naperville says it awarded 100% of the $280,000 budgeted for Renewable Energy Program incentives as of June 26, 2026. When money is all awarded, applications close for the rest of the calendar year. The city also says projects bought or installed in a year when funds run out will not be eligible for later incentives. So a project done in November 2026 will not be paid in 2027. If you want the city money, plan your project for early in 2027 and ask the city when applications open.
Nicor Gas as a back-up plan
Nicor does not run out the same way, but its rebates also depend on funding and end on December 31, 2026 for work done this year. Air sealing pays $500, attic insulation $400, wall insulation $150, foundation wall insulation $200 and duct sealing $600. A program-approved contractor must do the work. Before and after photos are required for insulation.
Naperville homes in numbers
The Census Bureau's survey for 2020 to 2024 says 25.8% of Naperville homes were built before 1980, the lowest share among the four Illinois cities we cover. Only 2.5% were built before 1940. That matters because Nicor's attic rebate only helps attics at R-20 or less, and newer homes often have more insulation already. Have an energy assessor measure your attic before you pay for work. About 62.8% of homes are detached houses and 86.1% heat with utility gas.
Windows: cost and benefit
The city's window rebate only covered replacing single-pane windows. Windows that are already double-pane did not qualify. Nicor's window rebates allow replacement of single- or double-pane windows, and an ENERGY STAR certification for the climate zone. The page does not say which windows earn $100 and which $125, so ask the contractor for the exact amount in writing.
Free help
The state's weatherization program serves households at or below 200% of the federal poverty level. It covers air sealing, insulation, and heating system work, up to $20,000 per home. Apply through a community action agency.
How to get an insulation rebate in Naperville
- Have an assessor measure your attic and test your air leaks.
- Call 630-305-5357 to ask when city applications open next.
- Hire a Nicor approved contractor for air sealing and insulation if you are going ahead in 2026.
- Take before and after photos and keep the invoice.
- Apply to Nicor within 90 days of the work or by January 31, 2027.
Common questions
Is the Naperville attic insulation rebate open?
No. The city says it awarded its full budget as of June 26, 2026 and closed applications for the rest of the year.
Does Nicor Gas still pay for insulation?
Yes. Air sealing $500, attic insulation $400, wall insulation $150, foundation wall insulation $200 and duct sealing $600.
Do I need a special contractor?
Yes for Nicor. Air sealing, insulation, duct sealing and window work must be done by a program-approved contractor.
Is there free weatherization?
Yes, for households at or below 200 percent of the federal poverty level.
Is the federal insulation credit available?
No. It ended after December 31, 2025.
What to do next
See Naperville heat pump rebates, the city's program page and Nicor Gas rebates.
By Sam Menard. Sources, last read October 6, 2026: Naperville energy efficiency grant programs, Nicor Gas residential rebates, US Census Bureau, American Community Survey 2020-2024. All Naperville rebates → Every Naperville Electric rebate →