Dave Sillman: Clean Energy Generation Goes Geothermal in Georgia

A homeowner near Atlanta bought a house that came with rooftop solar, three Tesla Powerwall batteries, and a geothermal heating and cooling system already installed. Geothermal is a type of heat pump: instead of moving heat between your house and outside air like a standard heat pump, it moves heat between your house and the ground, using buried pipes to tap into steady underground temperatures. Because it moves heat rather than burning fuel to create it, it uses much less electricity than a gas furnace and air conditioner.

The owner reports his power bill dropped from around $600 a month at his old house to an average of $60 to $70 now, with a high of $150 in winter. He credits the geothermal system with cutting heating and cooling costs by about 70 percent compared to a traditional furnace and AC, plus solar power covering daytime use and batteries covering nights. The system's waste heat also warms his water heater, trimming that cost too. He charges two electric vehicles using excess solar power, which matters in Georgia since the state does not have net metering, so selling surplus power back to the grid isn't much of an option.

He notes two downsides to geothermal: fewer contractors service it, so finding someone to inspect or maintain the system can take extra searching, and the upfront cost is higher, though he says the long-term savings can outweigh that, especially if the installation is financed. For homeowners not ready for a full system, he points to smaller first steps like air sealing and insulation, along with Georgia programs that offer subsidies for efficiency upgrades and heat pump conversions.