My father's parents had a huge coal gravity hot air furnace and on a visit in the winter I followed my grandfather down there where he would shake the grates and throw more coal in for the night. Sometimes a clinker would jam the grates and there would be lots of banging as he rumbled about that. In between the dining room and the living room was a big round iron grate where the heat came up and all of the big tubes fed cold air into the bottom of the jacket. There were little registers in the ceiling that could be opened to allow warm air to rise to the upstairs bedrooms. After he died around 1960, grandmother had the furnace converted to oil and had a water heater put in.
About the minimum outside temperature for the flue to work properly; is that because coal smoke is denser or heavier than wood smoke? If you lived in Atlanta where many older homes had a coal chute into the basement, did you have to worry about switching between wood and coal as the temperature rose and fell? We sure take a lot for granted now.
Those first units were far thicker than the Radiantubes and Frigidaire's first tube type surface units heated in very strange patterns. Cooking on them must have been a challenge when Medium Low was the setting for baking pancakes but it only heated an inner loop of the unit; not good for a large griddle. Friends had a range with those and I have one also. Being round tubes, they threw almost as much heat downward as upward. Still as has been said, they were a huge step up from a solid fuel range. I wonder if owners of a combination fuel range used the part over the firebox like a French top and did cooking on that when it was in use? Having never used a cookstove, I don't know what the speed of the hottest part of the top was like in comparrison to an electric surface unit, but since it was constantly hot and had so much mass, I would bet it was right fast. Given that the round top of the coal heated part of the Frigidaire combination range was directly over the fire box, there was probably no way to move pans to a cooler portion of that for slower cooking so maybe they had to be finished on the surface units, even if started over the coal-fired part. In O. Henry's The Gift of the Magi, there is the statement, "the pan on the back of the stove was hot and ready to cook the meat." I always assumed it was a solid fuel range where the top was constantly hot, given the time period in which William Sydney Porter wrote. I love how he called New York City "Bagdad-on-the-Subway." If any of you ever have the chance, try to see the 1952 movie O. Henry's Full House.[this post was last edited: 1/28/2012-18:23]
