Naperville homeowners had access to an unusually valuable local incentive for attic insulation in 2026. The City’s residential energy-efficiency program offered eligible Naperville Electric Utility customers as much as $2,500 toward qualifying attic insulation and air-sealing work.
The program was popular enough that the entire $280,000 budget for several Renewable Energy Program incentives had been awarded by June 26, 2026. That means the attic insulation incentive is closed for the rest of 2026.
For homeowners who missed it, the important question is what happens next. Naperville has not yet published the rules or funding for a 2027 attic insulation incentive, so another rebate should not be considered guaranteed. However, understanding how the 2026 program worked can help homeowners prepare if a similar opportunity returns.
How Much Was the Naperville Attic Insulation Rebate?
For 2026, Naperville offered qualifying homeowners up to $2,500 for attic insulation improvements.
The incentive was calculated as the lesser of $1 per square foot of attic insulation installed or 50% of eligible project costs. The maximum award was $2,500 per household. New construction was not eligible because the program was intended for insulation upgrades to existing homes.
Why Is the Upstairs Hot in Summer?
| 2026 Naperville Requirement | Program Requirement |
|---|---|
| Maximum attic insulation incentive | $2,500 |
| Incentive calculation | $1 per sq. ft. or 50% of eligible cost, whichever was less |
| Final insulation level | Minimum R-49 |
| Accepted insulation depth | At least 15 inches |
| Air sealing | Required |
| Eligible property | Existing residential home |
| Application deadline | Within 120 days of installation |
| Renewable Energy Program participation | Minimum $5 per month for at least five years following the award |
These were the requirements for the 2026 program and should not automatically be assumed to apply in 2027. Naperville will need to publish a new program guide before homeowners can know whether the incentive amount, eligibility rules, or available funding will remain the same.
Why Naperville Required Air Sealing Along With Insulation
One of the most important parts of the Naperville program was easy to overlook. Adding insulation alone was not enough to qualify. The attic also had to be air sealed.
That requirement makes sense from a building-performance standpoint. Insulation slows heat transfer through the ceiling, but it does not necessarily stop air from moving through holes and gaps around plumbing penetrations, electrical wiring, top plates, attic access points, recessed fixtures, and other openings between the house and attic.
ENERGY STAR recommends sealing attic air leaks before adding insulation. The U.S. Department of Energy's Building Science Education program gives similar guidance, recommending that penetrations through an existing attic floor be sealed before new insulation is installed.
This distinction matters because a homeowner can have a considerable amount of insulation in the attic and still lose conditioned air through gaps beneath it. Adding another layer of insulation without addressing those leakage points can leave an important part of the problem unresolved.
At Perma-Seal, blower door testing is already part of the attic insulation evaluation process. The test depressurizes the home and measures how much air is entering through leaks in the building envelope. Once those leakage points are identified, the old attic insulation can be removed where needed so penetrations and gaps are accessible for air sealing before new blown-in insulation is installed.
That process closely matches what Naperville required under its 2026 incentive.
What R-49 Means for a Naperville Attic
Naperville also required the finished attic to reach at least R-49. The City accepted a final insulation depth of 15 inches or more as sufficient for purposes of the program.
R-value measures how strongly an insulation material resists heat flow. A higher R-value provides greater resistance, although the actual performance of an attic also depends on air leakage, insulation coverage, installation quality, moisture conditions, ventilation, and other factors.
This is another reason simply measuring the depth of old insulation does not tell the whole story.
Perma-Seal has published blower-door testing results from an actual 1988 Naperville home that began with approximately R-12 batt insulation. Before the work, the home measured 2,464 cubic feet per minute of air leakage at a pressure of 50 Pascals. After air sealing and insulation work, measured leakage fell to 1,901 CFM, a reported reduction of 22.75%.
That does not mean every Naperville home will see the same improvement. Homes are built differently, and the amount and location of leakage vary considerably. It does demonstrate why evaluating the attic as both an insulation and air-leakage problem can provide more useful information than looking at insulation depth alone.
Can You Install Attic Insulation Now and Claim a Future Naperville Rebate?
This is where homeowners need to be particularly careful.
Naperville’s current rules state that projects purchased or installed after the year’s available funding has been exhausted are not eligible for future incentives. Because the City announced that its 2026 Renewable Energy Program funding was fully awarded as of June 26, homeowners should not assume that an attic insulation project purchased or completed later in 2026 could qualify retroactively for a possible 2027 incentive.
That creates an important decision for someone considering attic insulation now.
If improving comfort or addressing an obvious insulation problem is the priority, waiting several months for a possible incentive may not make sense. On the other hand, if receiving the Naperville incentive is an important factor in the decision, homeowners may want to wait until the City publishes the next program rules before purchasing or installing the project.
There is currently no published 2027 attic insulation program guide confirming that applications will reopen January 1, what the 2027 budget will be, or whether the requirements will remain the same.
What Naperville Homeowners Can Do Before the Next Funding Cycle
You do not necessarily have to wait to learn whether your attic needs improvement.
An attic insulation evaluation can establish the current insulation level, identify obvious gaps in coverage, and help determine whether air leakage may be contributing to uncomfortable rooms or high heating and cooling costs. Blower door testing can provide additional information by measuring the home's overall air leakage and helping locate areas that need to be sealed.
Homeowners interested in a future Naperville incentive should also become familiar with the documentation the City required in 2026. The program called for a paid, dated invoice that identified the insulation work, square footage, R-value added, final R-value, air-sealing work, and certain other eligible costs. Applicants also needed manufacturer information for the insulation and a current utility bill showing participation in Naperville's Renewable Energy Program.
Under the 2026 rules, applicants had to be participating in that Renewable Energy Program at a minimum contribution of $5 per month and continue contributing for at least five years following the incentive award. The contributions to that program are what fund these particular Naperville incentives.
Knowing those requirements ahead of time can make it much easier to act quickly if a similar program opens again.
Watch for Naperville's 2027 Attic Insulation Incentive
The speed at which the 2026 funding disappeared is probably the most useful lesson for homeowners considering attic insulation.
Naperville had $280,000 budgeted across several Renewable Energy Program incentives, including attic insulation, window replacement, rooftop solar, AC tune-ups, and furnace blower motor replacement. By June 26, the City reported that 100% of those available funds had been awarded.
If Naperville offers another attic insulation incentive in 2027, waiting until the middle of the year to investigate it could mean missing the available funding.
Our team at Perma-Seal already evaluates Naperville attics using blower door testing, air sealing, and blown-in insulation. If you’re considering an insulation upgrade, we can inspect the attic, measure where your home is losing air, and determine what improvements make sense for the house.
If receiving a future Naperville incentive is important to you, wait until the City publishes the applicable program rules before purchasing or installing the project. Once those rules are available, we can also determine how the proposed insulation and air-sealing work compares with the City’s requirements.
