The earth absorbs almost 50% of the sun's solar energy and stores it below the surface. The ground loop powering a geothermal system uses that renewable energy to heat and cool homes. Traditional forms of heating and cooling like natural gas, propane, oil, air source, etc. do not use a renewable energy to operate, so they can never be as environmentally friendly.
Traditional HVAC systems that use fossil fuels cannot be as efficient as a geothermal system because they require combustion (flames) to operate and provide heat. Air-source and ductless systems are also not as efficient as geothermal because they are creating warm or cold air based on the outdoor temperatures, which can fall well below freezing or on the opposite end, get very hot. Geothermal is transferring heat from the moderate temperatures below ground as opposed to the varying conditions we feel outside.
Compare Geothermal To Other Heating And Cooling Methods