Thermoelectric Stoves: Ditch the Solar Panels?

Thermoelectric modules: reclaiming waste heat from an oven or space heater with a power generator.

Any energy not converted by the generator remains heat, which was desired by the original usage (oven, space heater) anyway.

Fan cooling: using a fan to force air back in to the chamber which makes the process require less wood fuel.

Rocket mass heaters: efficient use of solid fuel but frowned by building codes.