Norwalk Looks to Us for Geothermal Heating & Cooling! We're Sherman Co. LLC. And we're distinguished throughout Norwalk, Iowa, for our geothermal heating and cooling expertise. Residents turn to us for ... first-class geothermal system installation and service experienced, highly trained personnel who understand every detail of geothermal heating and cooling - and know how to effectively communicate the process to you geothermal systems from one of the industry's most reliable names - WaterFurnace recommendation on how to maximize the potential from their geothermal heating and cooling installation Obviously, a significant reason people turn to us in the first place is for the savings they can realize on their energy bills with a geothermal system. Want a look? Give our Geothermal Savings Calculator a go. Then push forward with the next step and contact Sherman Co. LLC. We'll walk you through more of what makes geothermal systems the best choice for year-round heating and cooling comfort in Norwalk.