Examples from the Web for hypocaust
However, after the wood in the hypocaust was once well charred, the smoke was not so troublesome.
Doubtless we got our idea of the furnace from the Roman hypocaust, although the Roman invention had no special pipe for the smoke.
It had no cloisters, no hypocaust, no suite or sequence of rooms.London|Walter Besant
In addition to the hypocaust under the floor the wall was lined with flue tiles.
If there are no baths there is at all events an excellent specimen of a hypocaust, or Roman heating arrangement, to be seen.The Isle of Wight|G. E. Mitton