At first Roman houses simply had a fire in the middle of the room (the Latin for hearth is focus). But they probably had trouble with smoke as the Latin for living room is atrium (from ater meaning black). By about 400AD the Romans had perfected a form of central heating. The fire was lit outside in a furnace with hot air ducts under the floors and in the walls. Episode Contents: Models: Trying to start a fire with an electric drill. A Norman chimney vs a proper one. A life size 2 dimensional house model with radiators and boiler. A glass radiator. A balanced flue. Machines: Jacob's ladders by Rex. Guests: Solid fuel, oil and natural gas boilers. Films: Yet another silly 40's promotional film, this one for the Ascot gas boiler. Extro: The model house springs a leak.