The mirror image of this is combined heat and power (CHP). That is, instead of burning fuel to heat the home, use the fuel to power a generator of some sort, an

The mirror image of this is combined heat and power (CHP). That is, instead of burning fuel to heat the home, use the fuel to power a generator of some sort, and using the electricity to power the home. The waste heat (most of the energy from the fuel ends up as waste heat) is then captured to heat the home It's basically free electricity, if you were already heating the home by means of combustion anyway (e.g. oil, natural gas, propane).