NAPERVILLE, Ill. (CBS) — A Naperville mansion houses a cherished organization that serves 1,000 adults and children – many with autism.

But the historic Kroehler Mansion on Wright Street is so expensive to run that the cost could threaten the charity’s financial future. The group has a plan, as CBS 2’s Jim Williams reported Monday, but the town’s historic preservationists don’t like it.

“Construction started in 1908, finished in 1909 – a lot of history,” said Little Friends President and Chief Executive Officer Mike Briggs.

The Little Friends mansion offers an eye-catching 7,300 square feet of history in Naperville.

But if you take a casual walk past the mansion, what you don’t see is all the work that needs to be done here. And that work is expensive work.

“The electrical work goes back to 1908, so you’ve got the old cloth wiring,” Briggs said. “It’s not an elegant look. You know we make do with what we have.”

There are cracks in stained-glass windows, and water leaks.

And to stay in the mansion and keep it running costs $400,000 a year. And that is $400,000 that Little Friends cannot spend on its programs, and young people others who need its help.

“The people we care for, that’s exactly right,” Briggs said.

That’s a lot of money for Little Friends, which serves adults and children with intellectual and developmental disabilities and autism. The charity has been in the mansion since 1975.

“We’ve outgrown the facility, and honestly, we’ve outlived its useful economic life,” Briggs said. “Aside from the maintenance is that the demands for what we do are such that we need additional space to be able to meet the needs of the kids that are coming to us.”

Briggs wants to sell the mansion and move. He told us developers would offer top dollar for the property – but only if they could tear down the mansion.

The Naperville Historic Preservation Commission does not want that to happen.

But Briggs said a rehab job would cost more than $2 million, taking away resources from children like 3-year-old Lane.

“He didn’t know body parts, colors, shapes – he was barely speaking,” said Lane’s mother, Sarah Knudson.

His mom says Lane is doing so much better after his year here.

“He’s talking. He pushes in his chair. He knows his colors,” Knudson said. “It’s like we have a whole different child.”

Briggs and Little Friends supporters are appealing to the Naperville City Council to allow the sale – with no restrictions.

“We are being asked to bear the burden of historic preservation and the question is – is that fair?” he said.

Briggs said he has suggested the mansion be moved to another part of town, but no one has offered to do it.

The Naperville City Council is expected to vote on the mansion Tuesday night.