Tribute to floor furnaces
Purely nostalgic and random tribute to a technology that has disappeared with little trace. In Okla (and presumably other Southern states) floor furnaces were nearly universal from the '20s through the '50s. Around 1960 new houses started using forced-air heat, and by 1980 most floor furnaces had been replaced by forced-air. The switch to central heating and cooling systems was chiefly motivated by the cooling side. An Okla house needs 7 months of full-time AC and 4 months of part-time heat.
Despite their universality, I haven't found a single reference to floor furnaces in architecture books and planbooks of that era. All the specifications and pictures show central heating plants, either gravity furnaces ('octopus style') or steam radiators.
Undoubtedly the floor furnace was inefficient in numerical terms. It heated only one room unless you kept all the internal doors open. Most of its warmth went up to the ceiling and stayed there unless you had a ceiling fan to encourage convection. (Usually the bedrooms and bathroom had free-standing unvented heaters, which were rather dangerous and unsatisfying.)
But there's more to house heating than pure thermodynamics. After all, the purpose of heating a house is human comfort, not measured temperature; and the floor furnace provided more sheer comfort than any forced-air system.
After a shower, or after coming in from the cold, you could straddle a floor furnace and purr with pleasure, instantly warm from head to toe.
Forced-air registers simply can't match the experience. They blow warmish air part of the time, cold air part of the time, and no air most of the time.
The floor furnace had one important practical advantage. Because it didn't depend on electricity it continued working through a power outage, which is a fairly common occurrence in ice-storm-prone Okla.
In my Okla wanderings during the 1970s, the supposed inefficiency wasn't reflected in high gas bills. I don't recall dollar amounts, but I do remember that I never had to postpone paying a gas bill, while I sometimes had to skip the phone or electric.
Just as fireplaces require a set of equipment, the floor furnace had its own special accessories which tended to stay with the furnace even in poorly-maintained rental houses. There was a T-handled valve turner that reached through the grate to control the main and pilot valves, and a long match-holding 'reacher' that poked through the access port to light the pilot. The reacher required a fair amount of dexterity. Strike a wooden match, stab its cold end into the hole in the reacher, turn on the pilot valve, and quickly maneuver the match down to the pilot.