Underfloor Heating

The types available and the advantages and disadvantages of underfloor heating

Effectively heating up your home has become an easier task today. The traditional way to heat up homes was with the use of radiators. However, underfloor heating is fast becoming the number one choice in heating homes today.

The idea of underfloor heating is not new. The ancient Romans used the hypocaust system in hearting their homes and public buildings. The system composed of ducts that run under the floor built on raised bricks. Hot air from below run through the ducts and heated the floor above.

Another system was used by the Koreans. The system is called "ondol" which literally means "warm stone". The principle behind the system is a heated stove is placed below the floor level and a series of flues transport heat from the kitchen to the other rooms. This system was adapted by one Japanese client of the American architect Frank Lloyd Wright. Wright was so impressed by the indescribable feeling of heat radiating from below up. Frank Lloyd Wright adapted the "ondol" system for he thought it was the ideal and perfect way to heat a building. He began to incorporate the underfloor heating to his designs. He invented radiant heating with him using hot water running through pipes instead of the "ondol" system of hot air through flues. Today, the system has evolved though it is still based on radiant heating.

Today's use of multi-layer pipes in synchronization with highly efficient control systems and boilers, underfloor heating systems are very comfortable and convenient. With this system there is no longer a need for radiators that takes up space in a room. The heat produced by underfloor heating is even and consistent and dust is not circulated.

Two Types of Underfloor Heating System

With underfloor heating system, the whole floor serves as the source of heat. A room is heated from the floor up eliminating any cold spots that is evident in a radiator-heated room. Cold spot is possible in a radiator central heating system because the heat comes from the ceiling down. It is highly possible that not all the areas of room receive its equal share of heat. Underfloor heating eliminates cold spots as the heat is radiant rather than convected heat

There are two basic types of modern underfloor heating system: water-based and electric based underfloor heating systems.

  • Hot Water System: Warm water (50 degrees Celsius) is circulated through the tubes or pipes that are laid in the flooring. Pipes are usually multi-layered with a diameter of 15 mm to 16 mm. The water is heated to a lower than conventional temperature making the system suitable for a condensing boiler. The system is also compatible for heat pumps and solar powered water heaters. However there are other points to consider with this system. You have to take into account the soil conductivities that might add to heat loss and the vapour barrier or insulation of the flooring. You also have to take into consideration the placement of refrigerators, freezers and air conditioner units in the area that you want to put in water-based underfloor system.

Know in advance the type of flooring you will use as the material also has an effect on the overall heating capability of a water-based underfloor heating.

  • Electric Underfloor Heating System - The principle of heating is this case is the use of cables for heating. There are companies who manufacture cables in a mat where the mat in turn is laid on the floor. This system has a low installation cost too. All you need is a thermostat and the cables for the transport of heat under the floor. This system is well suited for small buildings i.e. residential and small commercial spaces.

The two systems are one in providing a consistent heat source under the floor. Each room that has an underfloor heating system installed has to be divided into zones where each zone can be heated and controlled separate from the rest of the system.

You should carefully take into consideration the specifications of a particular brand with regards to design and installation specifications.

Advantages of Underfloor Heating System

Generally, underfloor heating is easy to install and very cost-effective. It is "invisible" as it is embedded in the floor. It is almost maintenance free and requires no extra space to operate. You don't have to worry about reserving a space on the wall for a radiator. Underfloor heating does not require hot water which makes the system ideal for condensing boilers.

Radiant heat emitted by underfloor heating system is consistent and very comfortable. Traditional heating has warm air rise to the ceiling thereby heating the upper body, usually uncomfortably, while leaving the lower part cold. This is certainly disconcerting especially when you have to deal with stone cold flooring.

Tests conducted by independent companies bare that a more than acceptable indoor climate is where the floor temperature range is 19 to 29 degree Celsius and the air temperature at head level is 20 degrees to 24 degrees Celsius.

Energy consumption is reduced for the system calls for lower temperature water in the case of water-based underfloor heating system.

Disadvantages of Underfloor Heating System

The major disadvantage of the system is its slow response. It would take about 30 minutes for a wooden floor to warm up while a concrete floor could take one to several hours, dependent on the depth of the embedded piper or cables. However, to compensate, heat is retained longer and more efficiently. This would only be a disadvantage if the structure is occupied at certain time of the day only.

You cannot readily install underfloor heating all over an area. You have to take into consideration the positioning of floor mounted units, hot and cold water lines, refrigerators and freezers and even cabinetry.

In case maintenance and repairs are called for, you have to take out the existing flooring to access the heating cables or pipes. However it is safe to conclude that UFH is virtually maintenance free.