In our first geothermal book, Geothermal HVAC, Green Heating and Cooling (McGraw-Hill Professional, 2010, p16), Brian Clark Howard and I shared a dialogue from an article wherein a commenter said that switching from a gas furnace to ground sourced heating is increasing the burning of fossil fuels, because the power plant producing the electrical power is probably burning coal, natural gas or other fossil fuels. The argument seems valid until you understand what we call the “Negatherm Factor”.
“Negatherm” is a term that was coined to refer to energy that would or could have been used from fossil fuel consumption, but was never used. “Nega”, root of “negative”, meaning unused, and “Therm” a unit of energy equal to 100,000 BTU’s, usually measures the combustion of fossil fuels for heating a home or business. When heating from an appliance using electricity, we use “kilo-watt-hours” (kWh). Electricity comes from many different fuel sources including hydroelectric, solar, wind, hot rock geothermal, nuclear, natural gas, coal, and diesel to name a few. We are certainly seeing an increase in the renewable sources, the first four in particular.