@Algoz I know the fireplace (and the evergreens in the background) doesn't make sense, which is why I pointed out the inconsistency. Everything being 
said by characters points to such things being illogical. It's stupid, but just 'art' and not actual 'story'.
I imagine the climate being somewhat like Greece, which has average temp ranging from ~7°C at the absolute coldest to ~34°C at the absolute hottest. Which would 
not require building to keep heat, or preparing for winter, since just putting on warmer clothes would do. They seem to be behind our tech by a few centuries, so consistent temp indoors would probably not be a thing for them.
In all fairness, the cooking stoves 
would probably have small chimneys (even though the art shows the smoke rising into the room

), but would probably not be enough to heat the entire house. They don't have a lot of experience with smoke hazards, since they probably burn small amounts 
only for cooking, so they don't know the dangers. The people are panicking, and keep burning wood where they should 
not just to heat the house.
Imagine Greece, the land of sunny vacations, being hit by sub-zero temps and blizzards. It would be chaos.
Also, they didn't know about CO-poisoning. Any deaths were probably explained as being from the cold, so they 
thought that was way more dangerous than just breathing smoke.