The problem of furnace heating is that its effectiveness is reduced as it removes from the furnace itself, the uneven distribution of heat, temperature localization in one room. For heating the cottage and a small timber house, a Russian or Dutch stove is enough, but everyone knows — it is hot near the furnace, cool, and it also cools down. It is not possible to drown constantly, and if you close the hole of the hood at the wrong time, you can be poisoned with carbon monoxide or tap the room. The furnace is not so much heated by air as heated itself, and its thick stone walls gradually give heat, radiating it into space. The stove heating loses its effectiveness in drafts, so high thresholds were built in houses and palaces of the old time — a barrier of cold air.
