Cathedrals and churches

[ApotheosisMMC.]

Perhaps Europeans also knew about this technology?

The problem I see with the previous article on the Tartar chimneys is that the author clearly has an agenda and pushes his conclusions without presenting much data, while filling in the blanks with poorly supported assumptions.

While the chimneys are poorly designed, as the author points out, they also function well enough for many centuries to meet the needs of the European climate:

Thanks to modern heating systems, we can enjoy the cozy picturesqueness of a fireplace without depending on it to keep our homes warm. But that wasn’t the case in 18th- and early 19th-century America.

“Up through about 1800, the wood-burning fireplace—very popular with English settlers—was the primary means of heating a home,” explains Sean Adams, professor of history at the University of Florida and author of Home Fires: How Americans Kept Warm in the Nineteenth Century. “The problem was that winters in America can be much harsher than in England. The weather quickly exposed how inefficient fireplaces are at heating a room.”

The majority of the heat in a fireplace goes up and out of the flue. What little heat does make its way into the room gets concentrated directly in front of the firebox, leaving the rest of the room quite cold.

Beyond fireplaces: Historic heating methods of the 19th century

It didn’t take long for people to realize fireplaces were inefficient. So, how did houses stay warm?

archive.curbed.com

Until very late they became exclusively decorative:

1800s Fireplaces
Major shifts occurred in 1800s fireplace construction, function, and style. New fuel sources like coal gained popularity in post-Civil War America, with iron stoves and stove pipes providing radiant heating throughout the home without the need for expansive chimneys. Decorative mantels of the time often served as backdrops for coal stoves.

The dawning of the Victorian Era spurred a shift in design styles as well. Cast iron was not only a practical choice for fireboxes, but it also offered extensive potential for intricate ornamentation popular in this era, particularly for grates, surrounds, and other visible structures.

Smaller fireplaces and stoves became a fixture of social gathering spots like parlors, and ornamentations like elaborate mantelpieces, carvings, and tiles were adopted.

Early 1900s Fireplaces
The 20th century saw the advent of major changes in home heating, including furnaces and central air. However, the early-1900s fireplace remained important for practical and social purposes.

Designs of the time tended to feature smaller hearths and masonry fireboxes with millwork mantels. Decorative (non-heating) fireplaces were adopted as other heat sources gained popularity. In some cases, stoves were simply placed in front of existing fireplaces.

Explore the Rich History of Fireplace Styles | Old World Stoneworks

Discover the fascinating history of fireplace styles from ancient to modern times and discover timeless designs. Learn more at Old World Stoneworks!

oldworldstoneworks.com

The iron plate (which began to be introduced around 1500 and subsequently stopped using with the implementation of refractory brick in construction) and the "unexplained ornaments" of the same material could serve to improve the heat radiation system:

twofold purpose of protecting the material from which the fireplace has been constructed, be it wattle and daub, stone or brick, and reflecting the heat of the fire into the room. In their plain, unadorned state they are very easy to produce, requiring the preparation of a shallow, level depression in casting sand into which molten iron can be poured.

An introduction to British firebacks – Firebacks

hodgers.com

I am not going to analyze the air mass and smoke circulation system so as not to make this too long, since the intention and what was intended to be achieved are self-explanatory, at least partially with its various forms. The article exaggerates its ineffectiveness in smoke management despite not being totally optimal.
(I also complain about the lack of comparative evidence with supposedly unearthed Tartar structures)

Now, having said all this, I don't rule out the possibility that someone knew something else and the fireplaces had a secondary function, or at least accidentally ended up performing it. We have a rich tradition of stories where iron has certain effects against poltergeists and as a means of protection against certain entities, perhaps the heat on it amplifies these properties.
There's also this, although some effects may not be as potent because people weren't in direct contact with the hot iron of a fireplace:

June 20, 1998
Q: First question: okay, this book, The Key, by Cohane, is talking about a rock drawing in the Hoggar region of the Sahara; there is a figure of this man on these rock drawings surrounded by these various other figures; the man is pictured without a face. Where his face should be there are parallel brownish black lines that look like two things, the slats of a bed or the grill of a barbeque. Then, it says that "in the West Indies, and throughout North America, the indians had, as one of their most vital implements, a device that served as both bed and as a cooking utensil. It consisted of an oblong metal frame, three feet high, with slats or bars across the framework much like the slats of a modern bed. The indians cooked their meat on this grill over an open fire, and then, when the fire had died down, they wrapped themselves in their blankets and slept on the grill above the embers. To nomadic people, this object was the very center of their life. On this device, they not only cooked and slept, but also begot children. Out of this simple invention came what we today call a barbeque." Anyway, the thought that came to my mind as I read that was the idea of the magnetite in the brain and the representation of the darkened bars across the face of this god figure as being symbolic of iron magnetite, and some kind of energy transition going on in the head. Can you comment on this idea?

A: We need you to be more specific, if you please.

Q: Well, do the dark lines represent a)iron or b)the magnetite of the iron?

A: Seldom are answers so readily obtainable as in the "key" book.

Q: You got that right! It blew me away! So, in other words, the answer was very close to the description of the barbeque?

A: Interesting that they should mention "barbeque," as the lines described could very well denote the effects of the "grill" after one's face had been pressed upon it, while the fires burned underneath!

Q: What would be the source of such fires? The nature of the fires?

A: Firewalkers could tell you that.

{This was an interesting response since C___’s late husband was very interested in fire walking though neither Frank nor I knew it at the time.}

Q: What is the nature of the grill? Is it an external iron object, or an internal effect of iron?

A: Both.

Q: Why would this be represented as dark lines across the face?

A: When one is shamed, one is no longer seen, only sees...

Q: Are you saying that this is a representation of hiding one's face in shame?

A: More like being hidden.

 

[Persej]

Here is the article about those metallic objects in front of fireplaces:

Andiron

An andiron, firedog, fire-dog, fire dog or iron-dog is a bracket support, normally one of a pair, on which logs are laid for burning in an open fireplace, so that air may circulate under the firewood, allowing better burning and less smoke. They generally consist of a tall vertical element at the front, with at least two legs. This stops the logs from rolling out into the room, and may be highly decorative. The other element is one or more low horizontal pieces stretching back into the fireplace and serving to hold the logs off the bottom of the fireplace.[1] An andiron is sometimes called a dog or dog-iron.

Before the Renaissance, European andirons, almost invariably made entirely of iron, were of comparatively plain design. Indeed, andirons and firebacks were one of the first types of object commonly made in cast iron (introduced to the West in the 15th century), a trend which in England began in the 1540s: until the nineteenth century cast iron was too brittle for many uses, but andirons carried light loads and this was not a problem.[2] However, from the Renaissance onwards the front vertical element of andirons was increasingly given decorative treatment, and was in a different metal, such as brass, bronze or silver, which allowed casting, hugely increasing the range of decorative possibilities. When metals that could be cast began to be used for the fronts, these ordinary objects of the household received the attention of the artist, and had skill and taste lavished upon them. Thus English late 17th-century andirons often have elaborate flat brass front-pieces, often in openwork and sometimes using enamel for further decoration.

By the eighteenth century classical forms with several mouldings, similar to those used for candlesticks and the like, predominate in pieces for the middle classes, and were imitated in the American colonies, often just in iron and rather more simply. Small figures at the front also became popular; in America cast flat "Hessian" soldiers were a long-lasting favourite.[3] In Continental Europe, men such as Jean Berain (1640-1711), whose artistry was most especially applied to the ornamentation of Boulle furniture, sometimes designed them. The Algardi Firedogs commissioned from the Roman sculptor Alessandro Algardi for Philip IV of Spain by Velázquez in 1650 were copied in several foundries.

The andiron reached its greatest artistic development under Louis XIV of France (r. 1643–1715). From the eighteenth century, fireplaces increasingly had built-in metal grates to hold the firewood, or, increasingly, the coal, up off the floor and in place, thus largely removing the need for andirons.[2] However, andirons were often still kept for decorative reasons, and sometimes as a place to rest pokers, tongs and other fire implements. In older periods people used andirons as a rest for a roasting spit; they sometimes included a cup-shaped top to hold porridge. Sometimes, smaller pairs were placed between the main andirons for smaller fires. These are called "creepers".[2]

Andiron - Wikipedia

en.wikipedia.org

You can see them in a movie Killers of the Flower Moon. You can also see two different house designs. In William Hale's house the chimney is on the side of the house, but Mollie Kyle's house has the chimney in the center of the house, so the heat from the chimney is spread from the chimney into the house.

I suppose that the reason why fireplaces were not much popular in Eastern Europe is because they are not very efficient because most of the hot air quickly escapes outside. Iron stoves are not perfect either, but there are ways to improve that.

 

[Persej]

Here is another interesting fireplace that you can see in the movie The Current War. The real location is Cragside in England. These unusual fireplaces are just decorative fireplaces for the rich people, not something that ordinary people had in their homes.