Gusdai

Natural gas heating is around 95% efficient in a modern furnace (no soot, and steam is condensed to recover heat), so the carbon footprint comparison has something off (either they already consider the circularity of wood burning in the CO2 chain, or they compare different ways of heating: just locally vs the whole house).

Rocket mass heaters is basically the efficiency closer to a modern heater with a solid fuel (wood burning is otherwise super inefficient), but you still need fuel in the first place. There is no way you can heat a house fully from your cardboard scraps.

They're talking about the amount of soot. The heater produces little soot.

It still produces a lot of CO2 (and maybe carbon monoxide), so it needs to be vented out.

I know you're probably joking, but just in case: your whole Christmas shopping worth of cardboard, even if it's a full truck bed or two, probably wouldn't heat your house for a day. Cardboard is weak fuel.

It is though. If Russia gets to Kiev, it's game over. If Ukraine realizes they will not be able to get Russia out of the occupied territories, they will negotiate a cease-fire.

Conversely, if Russia loses occupied territories and starts getting its bases and infrastructure bombed on its own territory (including the Crimean bridge), with no perspective of gaining more ground, they'll negotiate a cease-fire too.

Basically the question is how much occupied territory will Russia be able to keep, if any.

Pretty important point: what is safe and what isn't in terms of fireplaces is not something you can necessarily learn by watching Internet videos and reading websites. Little mistakes in the design can have big consequences.

And your insurance most probably won't cover you if anything goes wrong; losing a house with no insurance money is not something everyone can easily recover from.