Random puzzlement #17,462

[light_in_motion]

Why are floor-mounted heating vents for hot air systems customarily placed nearest to the walls, where they're most likely to be blocked by furniture? Doesn't it make more sense to center them so the nice, expensive BTUs can spread out into the room before shooting straight up to the ceiling?

Comments

[hascouf]

They are placed near walls, and preferably under windows to aid in air circulation, or at least that is what the contractor that is retrofitting my in-laws house told them.

[light_in_motion]

Yup. I've certainly heard that before; it just seems counter-intuitive to me. Putting heating elements right under the least-insulated space on an outside wall seems silly. Presumably, there's something about the way it works that I don't understand.

I would think that the next most efficient design to a hypocaust or Siberian chimney would be centered hot air vents directly under ceiling fans.

[corwyn_ap]

For central heating, the design criteria is 'even heating'. Thus, heating units are placed next to the source of the most cold (windows etc.) so that the heat will appear even. In addition, the windows get washed with warm dry air keeping them from condensing water.

At least some of this is flawed in my opinion, and some more of it is out-of-date with modern building standards.

Ceiling fans, contrary to most use, should be blowing up in the winter, this mixes the air without providing a cooling breeze on the occupants.

Heat sources should be in the middle of the structure, preferably with high thermal mass, you are correct. What really gets me is chimney which passes through a wall. Wow, lose heat much?

[light_in_motion]

There isn't much to burn in Siberia. I've been told they traditionally built their houses around the chimneys, which wrapped around and around the structures. Apparently, the smoke would be stone cold when exiting, and one fireplace was sufficient to comfortably heat the whole shebang. In Siberia.

[roamin_umpire]

Great from a heat perspective, but not so great from a smoke perspective, I would think.

[light_in_motion]

The impression I got from the friend who told me about them was that the houses (hovels, whatever) were not filled with smoke. He didn't know how the chimneys were cleaned.. I did ask.

[corwyn_ap]

Chimneys are self cleaning. Once the creosote gets too thick it burns off the next time it gets really hot. All you need is a place to remove the ashes.

With weak-ass modern chimneys they call this a 'chimney fire'.

My understanding, from a smoke perspective, is that they are no trickier to light than a modern woodstove (i.e. touchy but not impossible), and once burning the draw fine.

The current problems with russian style stoves are 1) they take up a lot of space, 2) they are hugely expensive. Recommended otherwise.

[light_in_motion]

The current problems with russian style stoves are 1) they take up a lot of space, 2) they are hugely expensive.

IIRC, the description of a Siberian chimney wasn't the same as the one I just read of a Russian-style stove. The general principles of non-straight chimneys and using masonry to radiate heat into the living area were the same. In contrast, the firebox was open, and, I think, a wall fireplace, rather than a stove, although I'm not 100% sure of the latter.

The Siberian chimney was described to me as traditional architecture from a dirt-poor and unforgiving region; a place where wasting resources meant waking up dead. I'm sure it would be expensive to reproduce one here/now, since doing so would be a)custom work and b)complicated.

[corwyn_ap]

I have heard the 'siberian' and 'russian' terms used interchangably. I will have to look it up, I guess.

Not only custom, and complicated, but also not indigenous. There are few mason who understand it, so those that do can charge a premium.