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Case Studies: Mason City YMCA


Mason City YMCA & Rehabilitation Center – Mason City, Iowa

56,000-square-foot community recreation, sports and physical rehabilitation center, co-owned by Mason City Family YMCA and Mercy Medical Center-North Iowa.

Geothermal heat pump system:

Water-to-water heat pumps with a conventional VAV system.

Designed by Alliant Energy and installed by Durrant Engineers of Dubuque, Iowa.

Geothermal loop system:

Vertical loops of 1.25” pipe; 160 bore holes at 290 feet deep. Installed by LoopMaster of Indianapolis, Ind.

Annual cost savings:

$50,000 per year reduction in operating, maintenance and energy costs.

Project overview

In May 2000, one of Iowa’s largest geothermal construction projects began at the new YMCA & Rehabilitation Center in Mason City, Iowa. Alliant Energy designed the geothermal heating and cooling system and assisted with construction.

According to project engineer Durrant, Inc., the geothermal heat pumps also heat the pool during the winter, and reject normally wasted heat into the pool during the summer months.

The system also dehumidifies the pool area and uses rejected heat from the condenser sid of the heat pump to reheat the air.

Project benefits

The center will save about $50,000 in operating, maintenance and energy costs with the new system.

Geothermal technology also eliminated the uncomfortable cold and hot air blasts common with forced-air system, and it preserved natural resources – a key consideration for the project team.


“It’s exciting to be at the front end of technology,” said Mike Gulick, executive director of the center. “This project made a lot of sense for us because from a business perspective, the cost savings are impressive, and environmentally, it’s the right thing to do.”

“Our goal was to provide the new facility with an energy system that utilized alternative energy sources while remaining cost efficient,” added Hal Hudson, facilities director with Mercy Medical Center, co-owner of the center. “Alliant Energy put together a team of local and regional professionals that made it happened.”


Alliant Energy


Durrant – Dubuque, Iowa


LoopMaster – Indianapolis, Indiana