Of course, the people living there know best what they need, and with their current setups they mostly need wood for their stoves, or fuel for their generators, which are running electric heaters. But not all of them have stoves or generators.

So Generator -> Electric Heater is incredibly inefficient. People are likely doing this because it's all they have and they want to charge their electronics. If you want to provide equipment I would suggest:

• Mr Heater Buddy, 9000 BTU Propane Heater
• Propane Hose Assembly, you can find one for cheaper

This will allow them to connect to a standard propane tank. This setup is incredibly cheap to maintain esp. if they have access to a Amerigas/Rhino propane exchange or propane fill-up station. The buy-in here is around $140 per tent but you can get it down cheaper if you get a generic hose. The maintenance cost of exchanging/refilling the propane. On the 4000 BTU burn, this can last about half a month with a standard 20lb propane tank and should be more than enough to heat a tent. Monthly this has a cost of about $40 depending on how much propane is locally. Since the heater is radiant it's heating the person / objects in the tent not the air meaning it's incredibly effective.

This setup is really beneficial because it's easy to adapt to different living circumstances whether you're in a tent, a car, etc. In a pinch it can keep you comfortable enough in a single-wide too.

If you guys want to build something, reducing fuel costs during the day can be achieved by building a solar collector