HOLLAND, MI -- For more than a quarter century, Holland has spent millions to heat its streets and sidewalks during the winter.

With 168 miles of tubing coiled beneath the concrete, it's the largest publicly-owned snowmelt system in the country, according to the city's research.

Most of the capital is invested in laying that intricate tubing system beneath sidewalks and roads, circulating hot water derived from the Holland Board of Public Works' cooling system.

Since 1998, the city and its public entity have spent nearly $8 million on the project, according to BPW estimates.

"The year the first part was put in, it came with great relief that the operating costs were less than expected," said former Holland Mayor Al McGeehan, who was a councilman at the time.

That was good news particularly for downtown property owners who are assessed a tax to cover the cost. The city pays for the installation, and part of the assessment is to cover that capital cost recovery.

"It was a huge gamble to go ahead with it because there was no template," McGeehan said. "There was no previous numbers we could look at it. It was unique, it was novel and was it untested and untried."

McGeehan, who was a Fifth Ward councilman at the time, remembers being among those asking lots of questions about how much the system would cost to install, and then to operate.

Industrialist Ed Prince, who proposed the plan, stepped up with $250,000 in funding. His investment made the decision easier for city officials.

Prince believed snowmelt would make Holland's main street competitive with the amenities of the then-new mall going up along nearby U.S. 31.

Prince, who died in 1995, was right. The downtown flourished and grew, earning recognition from The National Trust for Historic Preservation as a "Great American Mainstreet."

Holland's snowmelt system uses waste-heat cooling water from the city's James DeYoung power plant, located blocks from downtown along the Lake Macatawa waterfront.

The miles of tubing also provides a way to cool the heated water before it is released into Lake Macatawa, as it heats the streets to keep them free of accumulated snow.

The system was expanded several times to include the market area at the Civic Center, the sidewalks to Herrick District Library and the ramps to the parking deck on 7th Street.

In November, the city completed a nearly $4 million snowmelt expansion on Central Avenue on sidewalks between Sixth and Ninth streets, and in the roadway and sidewalks on Eighth Street between College and Columbia avenues, said Dana Kollewehr, the city's downtown director.

Next year, the snowmelt will include the Columbia Avenue sidewalks between Seventh and Ninth streets and the west-side sidewalks on Central Avenue from Ninth to 20th streets after the source of power for the system is switched to the Holland Energy Park.

The new gas-fed energy plant, going up east of downtown, will replace the city's coal-fed plant.

The system - which costs between $20,000 to $80,000 to operate annually -- saves money by eliminating the need for salting, plowing and by extending the life of sidewalks by avoiding frost heave.

The amenity also cuts down on slipping and sliding, and snow being tracked into stores.

Snowmelt is made up of about 10.5 acres of heated sidewalks and streets. By 2017, the system will increase to more than 14 acres when the final phase of this year's expansion is operational.

It is designed to melt an inch of snow per hour at 20 degrees Fahrenheit, with 10 mph winds.

The infrastructure is so popular that earlier this year a group of private donors raised $500,000 to expand snowmelt to Evergreen Commons, about 12 blocks south of downtown Holland.

Some of the donors include Dick Haworth, chairman emeritus of eponymous Holland office furniture-maker, and Prince's daughter, Emilie Wierda. Her philanthropist parents founded the nationally-recognized senior center.

McGeehan, who is now the chairman of Evergreen Commons, says the group wants to create a walkable, age-friendly town.

"I firmly believe that if we just look at what happened to downtown Holland, we are going to see investment along snowmelt," McGeehan said.

The expansion project is expected to begin in the summer.

Shandra Martinez covers business and other topics for MLive. Email her or follow her on Twitter @shandramartinez.