Marshalltown, Iowa, Geothermal Sherman Co. LLC is the premier WaterFurnace geothermal contractor in Marshalltown, Iowa. We'll help you understand all the benefits of geothermal heating and cooling. We’ll see to it that your WaterFurnace system is correctly installed, too. And when it comes time for service? Nobody in Marshalltown can beat our service! Contact Sherman Co. LLC today. Like a little up-front look at the savings a WaterFurnace geothermal heating and cooling system can give you? Use our easy Geothermal Savings Calculator.