Mostly older houses do (< 50s), and yes, wood is the most cost effective.

This house is > 70s, doesn't have a chimney, but we're considering installing a cast-iron wood burner in the house center for this winter.

Firewood was in short supply and hard to find this winter and spring because of high power prices, imagine what will happen this coming winter with prices 5X-10X.

It's still a country with a lot of wood, finding a farmer willing to sell some even at the worst of times, are easier than any alternative.

There's sellers that are already out of stock. Firewood needs to dry for months before use, and like everything else when there's high demand there will be high prices.

https://www.aftonbladet.se/minekonomi/a/66p5LQ/ved-rusning-l...

Maybe I can flip my 3 cubic meters of really shitty pine wood for a new graphics card this winter..? Not gonna afford to run it for a while though...

Yeah, these are hard times, I wouldn't bet on finding wood unless you know someone.