a rough survey of energy sources in a prepper situation

Gasoline/diesel generators

• Con — Loud. They're not stealth AT ALL.
• Pro — Probably the most mature, compact, and economical of any generator available.
• Con — Burns a very limited range of fuels.

Biomass generators

• The most common example is the BioLite wood burners.
• Pro — Pretty quiet.
• Pro — Can handle a variety of fuels.
• Con — Incredibly inefficient and weak.

Other way of converting heat into electricity inside the home

• Nope, it pretty much won't work. Sorry

Solar cells

• Full-black solar panels are available. If you put these flat against a window, they would be somewhat stealth.