A ‘data center next to homes’? Naperville council weighs Karis development

After months of highly charged debate, a data center proposal heads to the Naperville City Council Tuesday night.

Along the way, the developer, Karis Critical, has revised the scale of its plan. But it’s no less controversial.

“At the end of the day, the biggest issue is that having a large industrial facility such as a data center, and in particular, a data center next to homes, does not make any sense,” said James Butt, a technologist who has consulted for data center companies and customers who have moved into them. “Other municipalities have learned this the hard way.”

Karis earlier proposed building two data centers near Naperville and Warrenville roads. The current request calls for a single data center.

“We have consistently worked to right-size the project for Naperville,” said Russ Whitaker, an attorney for the project.

The city council is considering a draft agreement establishing conditions for its construction, operations, noise mitigation and annual reporting. For instance, the data center must purchase all of its electricity from the city. Peak load is capped at 36 megawatts. The availability of electrical capacity to serve the facility is subject to the availability of electricity to the city from ComEd.

Karis also would “guarantee that there's not cost increases to other Naperville consumers as a result of the increase in the electric load,” Whitaker said.

“So effectively, any increases to electric cost caused by the data center are going to be borne by the data center, and that’s both in terms of infrastructure improvements, but then also long-term electric rates,” he said.

Butt, who lives nearby, said these are the things that the city should be requiring of any data center or large load customer.

“But I still don’t think it’s appropriate from a zoning perspective,” he said.

The concerns

Residents say many homes are hundreds of feet from the proposed facility.

“Everyone wants to develop Naperville,” Naper Commons resident Sujay Shah said. “People are actually for data centers. I myself am for data centers. I recognize how important they're going to be for our future in terms of how we progress in the world, but they have to be placed responsibly.”

Of significant concern is the exhaust from diesel generators. Neighbors cite the American Lung Association’s 2025 “State of the Air” report, which showed DuPage County with an “F” grade for particle pollution.

Up to 24 generators would be located in an enclosed yard. Under the agreement, no more than two can be tested concurrently. Generator testing can only occur on weekdays and cannot exceed 10 hours per year. Non-emergency use is restricted during poor air quality — “some good regulation,” Butt said.

Neighbors are also worried about noise from HVAC units.

“There is a lot of low hum from those cooling fans that can be heard from miles away from these facilities,” Butt said.

He said the city should update its noise ordinance “to be more applicable to this type of industrial noise” and codify the distance allowed between a data center and houses.

“Other municipalities have tightened zoning and pushed back against data centers near homes as the long-term impacts, noise, 24/7 operations and industrial encroachment have become clearer,” Clara Lambert told the council in December.

The property is along the city’s I-88/Diehl Road corridor. A study commissioned by the Naperville Development Partnership suggested focusing development efforts on sectors such as ag or food tech and production, fintech, quantum or advanced computing, pharma and life sciences. The study also described a vision for a more vibrant, “live-work-play” environment along I-88.

“Let's ask ourselves, might the Karis proposal on this particular parcel foreclose future, higher-value development opportunities?” Sarah Baugh told the council.

Future development?

A city staff report cautions that the data center “may have an impact on the timely availability of energy for future development” in the I-88 corridor.

In analyzing the additional 36 megawatts of capacity needed for the city’s electric utility to provide energy to the data center, the city provided its consultant and ComEd with projected load growth through 2030, and the conclusion was that there is sufficient capacity available to handle reasonable growth over that time, according to a staff memo.

However, it’s unlikely that the city would be able to accommodate another large load customer without significant improvements.

If Karis doesn't use it, “there's absolutely no reservation of that load in Naperville for future development,” Whitaker said.

“So I think it's sort of a fallacy to suggest that this is going to be a limit on Naperville’s future development in the corridor. The general availability of electricity is a limit on Naperville’s future development in the corridor,” he said. “While this is certainly consuming electricity, Naperville can always ask ComEd for more.”

Karis has pledged to invest at least $250 million, exclusive of tenant IT infrastructure, which would “represent additional investment of hundreds of millions of dollars.”

Whitaker has called the Indian Hill substation a “unique resource that positions this property to be developed as a data center.”

“It will be a significant revenue generator for the city,” he said. “It will maintain the integrity of that research and development corridor, and it will establish a high-tech future job base in the city of Naperville.”

Acknowledging health concerns, Whitaker said emissions modeling is being done.

“We're trying to go above and beyond with studies to prove that we're responsible actors,” he said.