Mason County, Washington, Geothermal Heating & Cooling We're getting the word out in Mason County, Washington: in in the condition the economy is in today, geothermal heating and cooling is absolutely the right choice! Ground conditions in Mason County are perfect. How about our seasonal temperatures? They fluctuate enough in highs and lows to practically guarantee that geothermal heating and cooling will offer the best year-round comfort. You'll love how much a geothermal system can cut your energy expenses, too. The proof? Take a look at our Geothermal Savings Calculator. Contact Thermal Systems today. We've got quite a bit more to tell you about the benefits of geothermal heating and cooling in Mason County. Another great thing, we install and service WaterFurnace geothermal systems, the best on the market.