Very Neat!
That example is very well preserved! The base and wall cabinets in the kitchen have been replaced and the tub surround is not original. The furnace isn't original, but it looks like the system itself is. The ceiling panels consist of sandwich panels with a upper and a lower skin with an open cavity between. The original furnace circulated hot air through a closed loop of those panels, from the furnace, over all of the rooms and back to the furnace. The panels then radiated the heat downward into the living space. That appears to still be the system. Not sure just how effective or comfortable that would be in Ohio, but apparently someone was happy enough to keep it working just as it has always been. Even the colors (except the black china cabinet) are original.
This is a nice time capsule - would look fabulous with some time-appropriate furnishings.
lawrence