After the fall of the Roman Empire, Central Heating would not reappear until the 20th century. So, the next time you shuffle over to crank up your thermostat or enjoy a hot bath, take a moment to appreciate the skilled tradespeople of old that laid the foundation for our Heating Systems of today!
Tales of the Trade – Origins of Central Heating
By Brandin Bursa - HARDI
At this time of year, we all can appreciate the comfort of Central Heating. Without it, our winters would be far more miserable, and our clothes would reek of fireplace smoke.
While adjusting your thermostat, have you ever wondered when Central Heating first came about? If your mind led you down a path to the Roman Empire over 2000 years ago then you’d be correct. The Romans were the inventors of the Hypocaust System, the precursor to our modern Central Heating systems.
The Hypocaust, translated as “the fire beneath”, was used to heat the Roman Bathhouses and the homes of the wealthiest citizens. Surviving ruins of these systems can be found throughout Europe, Western Asia, and North Africa.
The system was designed to circulate heated air beneath the floors and through the walls of the dwelling, providing radiant heat. Structures with Hypocaust Systems were built with raised floors supported by uniformly placed pillars. The raised space was left open to allow the air to circulate beneath the dwelling above. The floors were comprised of tile and concrete slabs to allow for comfort and heat transfer. The walls also contained tiles and hollow bricks to help radiate the heat throughout the room. The hollow bricks also acted as the flue, allowing the heated air to exit out the roof.
The heat source was a furnace located below the dwelling and closest to the area wishing to be warmest. This furnace had to be tended to continuously which was the main reason this system was generally only available in public bathhouses or in homes of the wealthy. Twigs and small branches proved to be the ideal fuel sources as logs took too long to burn and did not perform as well, again leading to a very labor-intensive effort.
The system’s design and construction remain an engineering marvel because it did not allow for carbon monoxide leakage. Modern-day efforts to recreate these types of systems without carbon monoxide leakage have proved difficult; showing once more the skill of the tradespeople tasked with designing and installing these systems thousands of years ago.
When used in bathhouses, the system was far larger and more robust. There could be multiple furnaces and many flues to be able to distribute the heat properly. Roman Bathhouses had numerous different rooms with specific purposes and required varying temperatures, ranging from cool to very warm (120°f). Socializing at Bathhouses was a major aspect of the Roman lifestyle, hence their widespread usage throughout the Roman Kingdom.
By using a hypocaust system beneath a bath space, the water could be heated and circulated by way of convection. The warm water would rise, and the cooler water would cycle back to the portion of the bath that sat directly above the furnace. Talk about going to great lengths to enjoy a warm bath.