[midoridensha]

It's worse than that. The sap in it will collect in the chimney and then cause a chimney fire. You really don't want to burn that stuff in a fireplace.

[fifilura]

I'd say that is a symtom of bad combustion (too little air). Not what kind of wood you use. Sap burns just fine.

[alrlroipsp]

It's both too low temperature burning leaving resiude in the chimney that can catch fire later, AND pine/spruce having way too much sap to burn alone. You should absolutley mix it with other wood when you burn it, same as oak.

[fifilura]

Fair enough. Feels like you have more (possibly hard-earned) experience than me on this issue.

[TEP_Kim_Il_Sung]

So use a rocket stove? Burns too hot and efficient to leave residue.

[yibg]

Yeah, let me just dig the old rocket stove out of the basement and fire it up.

[TEP_Kim_Il_Sung]

They are fairly easy and cheap to construct, plenty of guides for rocket stoves, and rocket mass heaters.

Want to heat an entire garage 24h with a hand full of twigs? An ordinary oven can't cope.