[dyauspitr]

Yeah fireplaces don’t make sense to me. Hot air rises and it sucks the existing heated air in the house which all flows out. The only way to heat the space is you need something with a lot of thermal mass that heats up in the process and then radiates heat. So a lot of bricks around the fire, some sort of baffle to enable the heat transfer and a system that sucks in air from the outside.

[8jef]

What you imagine is called a rocket stove mass heater, and it has other names too. Works wonderfully well.

[foobarian]

We saw stoves/fireplaces like this in a bunch of taverns in Slovenia. Huge hulking tiled cubes around the center of the building that just radiated a pleasant heat from every square inch of the surface. I imagine it was quite efficient, with just a very low fire burning to keep it in equilibrium.

[pluralmonad]

If it was a rocket stove, it was a very small very hot fire. I've had a bit of a love affair with rocket stoves lately (even replaced my BBQ/grill with one).

[ynac]

I like the idea of an outside vent, and unfortunately, I think an insert of some kind. I can't help but first think of the goofy look of a wood fired stove sitting half in and half out of the fireplace. Surrounded by a few tons of river rock. That said, after a couple days of a couple degrees, it's either that or the tent in the basement.

[dyauspitr]

*outside intake. The vent would just be the chimney.

[bluGill]

The problem with outside vents is sometimes smoke goes out them - air comes down the chimney.

[praptak]

It's challenging to design the exhaust so that the smoke goes away, but not too much heat.