A neighbor across the road said last year he had a hard time keeping his house 65 but tells me how he can burn green firewood in his outside wood furnace.
He had his house insulated better (walls & ceiling) before he had new siding put on so I would think it's the wood. I'm not sure when he cuts his wood but I'm seeing him still coming in with trailer loads of splits.
I hear the same thing down here about outdoor burners. I think it may be a misconception based on the idea that if a (chimney/stack fire) does result, it’s contained within the burner and ultimately, poses a far less severe fire risk to the dwelling. I am in the insurance business and see outdoor burner covered in creosote all of the time.
Lots of guys leave the splits very large for those things. My guess they don’t come anywhere close to seasoning long enough for splits that large. Sometimes I see 12-14 inch rounds just halved and then stacked. Maybe even a little larger.