Kansas City, Mo. ? Robert A. Long and his family were rich, but when it came to cooling the house they were no better than everyone else: They had to open the windows.

Now the family’s 100-year-old mansion on Gladstone Boulevard, which is home to the Kansas City Museum, is being retrofitted with modern climate controls as part of a multimillion dollar project funded so far by public money.

But you don’t just stick a bunch of window AC units in a house that’s on the National Register of Historic Places. You have to be creative.

That means excavating a hole 30 feet across and 26 feet deep in which to conceal a large cooling tower.

“We’re the only historical museum in the city with a pit like this,” quipped Christopher Leitch, director of the museum.

The bustle on the grounds is the latest part of a project to restore and update the mansion. The roof and exterior windows of the big house have been replaced or restored. Work being done now will allow efficient heating and cooling of the 35,000 square feet in the house as well as the separate carriage house.

The investment so far has been a little more than $10 million in city bonds and sales taxes.

Modern heating and cooling is required to protect the buildings and preserve the artifacts to be displayed. The pit will hold the cooling tower, which would be loud and intrusive if it sat above ground.

“It was the best solution we could come up with,” said Todd Sharbono, managing engineer for the Kansas City Museum.

Gary Marsh, president of the museum advisory board, said an alternative was to sink about 250 wells deep into the earth to tap geothermal energy. But that would have been too costly and would have required wells all over the museum grounds and on Scarritt Point parkland across the street overlooking the river bottom.

The system chosen after about 18 months of planning was designed by Smith & Boucher Inc. and includes concealed duct work inside the historic buildings.