The History of Underfloor Heating

Underfloor heating throughout history has been used as an effective heating solution right until the modern day. Modern innovations have made it more accessible to a wide range of homeowners, and it wasn’t so long ago that it was considered a luxurious addition for the wealthy.

In this article, we take a look at the history of underfloor heating through the civilisations that invented, innovated and produced them, as well as how this has been adapted to the modernised systems that exist on the market today. If you are looking to find out more about an underfloor heating system of your own, then enquire with Easyflow online or over the phone.

Who Invented Underfloor Heating?

No inventor has been attributed to the original creation of underfloor heating. The first discovered underfloor heating systems were made by the ancient Koreans, thought to have been invented in 5,000 BC! These floors were either heated or baked by a fire, which would later be coined as ondols, meaning “warm stone” around the end of the 19th century. Evidence suggests that early ondols started as gudeuls, which were essentially a cooking and heating system in the home.

When a fire was lit inside the furnace to cook, the flame would extend horizontally because the flue entry was situated beside the furnace. If the smoke were to travel upwards, the fire would have extinguished too quickly, and you wouldn’t be able to cook your food long enough. After the flue, a series of passages would guide the flame and smoke under the floor to warm it. Entire rooms were built around the furnace flue to create rooms that could enjoy heating from the floor!

When Was Underfloor Heating Invented?

We know the progenitor underfloor heating systems were invented as early as 5,000 BC. Modern systems as we know them started development in the 1800s and would not receive widespread standardisation until the 1980s. By 3,000 BC, the Koreans were still using the ondol fire hearth system. It has also been thought that a double hearth system was being used in 900 BC, with one hearth being used for cooking and another as a heating system.

350 BC showed the earliest documentation of the Ancient Romans & Greeks using their own version of the ondol called the hypocaust. These systems raised the floor on pillars, allowing hot air to pass through the space beneath to heat the flooring. They were commonly used in bath houses, public buildings, and the homes of the noble and merchant classes. The lower classes seldom experienced it in their own homes.

The Movement Towards More Advanced Underfloor Heating Methods

By 500 AD, there was a noticeable difference in how Asia and Europe heated their homes. The Europeans’ heating system of choice was the open fire system, whereas the ondol and gudeul were being developed even further in Asia. The homes of the upper class and palaces in Asia utilised a far more sophisticated form of fire-based underfloor heating by around 700 AD.

That doesn’t mean underfloor heating left with the fall of Rome. Hypocausts were still used extensively in both public baths and private homes around the Mediterranean. When we observe underfloor heating systems in 1400 AD, we see extensive and sophisticated hypocausts such as the Turkish Baths built by the Ottoman Empire. Hypocausts were still in use as late as 1904 at Liverpool Cathedral.

Though reliable for centuries, ondols and hypocausts had a significant drawback: dangerous levels of carbon monoxide. Leaks from the cavity floor or flue could lead to serious health complications. Thus, around the 1900s, many architects, inventors, and engineers began experimenting with more efficient and safer forms of in-floor heating.

A Throwaway Discovery Leads to an Invention Vital for Modern Underfloor Heating Systems

In the 19th century, extensive research was being put into developing the modern central heating system using water boilers and piping systems. This included research into thermal conductivity, surface reflectivity and surface emissivity. A discovery that was a throwaway at the time, but would become a vital component in wet underfloor heating systems.

Hans von Pechmann in 1899 found a waxy residue at the bottom of one of his test tubes during an experiment. His colleagues Eugen Bamberger & Friedrich Tschirner coined this waxy residue as polymethylene. This was discovered during the auto-decomposition of diazomethane in ether but was eventually discarded. This polymer is virtually identical to polyethylene, which was discovered by Eric Fawcett & Reginald Gibson in 1933. This time, the results saw industrial use of polyethylene in 1939 as use for insulators for radar cables in the Second World War. Later, it would be used as flexible piping that makes modern floor heating setups possible.

Who Invented Modern Underfloor Heating?

Many public figures in the 1900s have been credited with laying the foundation for modern underfloor heating. One of the most notable was a British Professor named Arthur H. Barker, who discovered that small hot water pipes embedded in plaster or concrete were very effective as a heating system. In 1907, he patented the “panel warming” system and sold this to R. Crittal & Company. The concept of the patent was used to heat the Royal Libre building in 1909. This effectively marked the start of “wet”, or “radiant” underfloor heating.

These systems weren’t perfect, and most developed before 1937 failed because of problems with condensation buildup. These were mitigated through the use of ventilation systems, but it was obvious that more needed to be done to improve the design. That said, architects like Frank Lloyd Wright widely popularised the usage of underfloor heating in his projects around this time.

The 1940s in the US saw a large-scale building operation that installed radiator-based heating systems into many new homes. This proved that water-based systems could be incorporated into any design project and would pave the way for the modern central heating system to be installed in a huge number of homes. In the 1960s, we saw the first wet underfloor heating system for the home invented in Canada.

By the 1980s, modern wet underfloor heating systems were becoming commonplace in homes across the globe. Korea remained the leading users of the system, with it installed in nearly all Korean homes. Market acceptance in the West was slower, with cheaper radiator-based systems taking priority.

How Does Radiant Floor Heating Work?

While the ondol and the hypocaust distributed hot air through a cavity under the floor, radiant heating distributes heated water through a network of pipes. These pipes then emit heat to warm the room from the ground up. Using a network of thermostats and an underfloor heating manifold, tighter control of the distribution of hot water is managed automatically to ensure efficient heating that is only on when required.

In the 21st century, we saw the introduction of a new system in the form of electric floor heating. These took the technology of the electric blanket, first invented in 1912, where a mat containing electric coils would become hot when an electric current was passed through them. With new modern safety features and thermostat integration, these mats could be installed underneath a flooring finish.

Since these systems have become more accessible, they are also becoming a common feature in new-build properties as well as a retrofit option for older properties. This is because the design can be incorporated into the build of most properties without compromising integrity.

What can the Past Teach us About Underfloor Heating Systems?

Once a fire-based system that was associated with nobility, expensive buildings, and unique complexes, underfloor heating is now a highly popular heating system for homes across the UK.

The history of underfloor heating systems spans thousands of years and allows us to see why they are still such popular heating systems today. These weren’t just status symbols for the wealthy, but the means to heat rooms effectively, cook food, and provide a comfortable experience. Architects like Frank Lloyd Wright and inventors like Arthur H. Barker recognised the appeal and the efficiency of the hypocausts, paving the way for widespread adoption and innovation.

Though price and an inability to retrofit were the primary obstacles to widespread underfloor heating uptake in the past, the modern solution has been developed to be as accessible as possible. Now it can be used as a replacement system for other conventional heating methods, such as radiators and electric heaters. You’ll enjoy more even heat distribution, and there won’t be any cold spots in the room!

Luxurious and comfortable as well as efficient, underfloor heating is a great improvement for your home. When installed in tandem with insulation and liquid floor screed, you can enjoy a wide range of luxury flooring finishes.

If you are thinking about installing an underfloor heating system in your home, then contact one of our experts today!