St. Mary's, Maryland, Geothermal Heating & Cooling We're getting the word out in St. Mary's, Maryland: in today's economy, geothermal heating and cooling is definitely the smart way to go! Ground conditions in St. Mary's are just right. How about our seasonal temperatures? They change enough in highs and lows to practically guarantee that geothermal heating and cooling will provide the best year-round satisfaction. You'll love how much a geothermal system can cut your energy costs, too. The proof? Our Geothermal Savings Calculator. Contact Ground Loop Heating & Air Conditioning, Inc today. We've got quite a bit more to tell you about the advantages of geothermal heating and cooling in St. Mary's. Best of all, we install and service WaterFurnace geothermal systems, the best on the market.