Underfloor heating

Underfloor heating is a system in which heating is provided through the floor. The system can be hydronic or electric and heats the ambient air in a room without any apparent heating appliances. Various improvements have been made to this very advanced type of heating in recent years to make it easy to install and improve its ease of use.

How does underfloor heating work?

Underfloor heating is an invisible installation that heats the temperature of a room by transmitting heat from the floor into the ambient air. There are two types of underfloor heating:
  • Hydronic underfloor heating
Hydronic underfloor heating uses a hot water circuit installed under the floor. A network of flexible pipes covers the entire surface area of the room. The pipes are laid on thermal insulating plates covered with cast screed, then a floor covering. The heat of the water flowing through the pipes increases the temperature in the room. The screed distributes the heat evenly, as well as providing a flat surface for fitting the chosen floor covering (carpet, tiling, parquet flooring, etc.).
  • Electric underfloor heating
In electric underfloor heating, the heat is delivered through a circuit of electrical elements in the floor, rather than through hot water pipes. These are covered with insulating plates and cover the entire surface area of the room to distribute the heat evenly. The system is connected to the power circuit of a home or building.

Underfloor heating can be installed in all types of situations: public spaces, offices, residential homes, stores, etc. provided that a few energy efficiency conditions are met and the appropriate materials are used.

Common misconceptions about underfloor heating

Underfloor heating has had a bad reputation for a long time: because it delivered excessive heat, it was criticised for provoking circulatory problems during the 1960s. Current systems no longer cause this problem as they deliver a mild heat and the temperature on the surface of floor doesn't exceed 28°C. The French standard DTU 65.14 limits the temperature of the water flowing through a hydraulic floor system to a maximum of 45°, and the greater the surface area of the room and the more conductive the materials used, the lower the circulation temperature of the fluid. Discover all our products

The benefits of underfloor heating

There are many benefits to installing underfloor heating, both from a comfort and energy-saving viewpoint.
  • Underfloor heating: comfort above all
Underfloor heating delivers a comfortable temperature and a warm floor, even when walking around your home barefoot. The heat is uniformly distributed in a room, which isn't the case with localised heating such as a radiator. The fact that the heat radiates from the floor ensures consistent delivery in every area, with no temperature differences. The heat is distributed everywhere, with no cold areas or unnecessary air circulation.
  • Underfloor heating: an invisible solution
Another benefit of an underfloor heating system is that it's invisible, as the pipes or elements are hidden under the floor, so it integrates seamlessly into the interior. It also saves a significant amount of space, both on the floor and on the walls, leaving these areas free of radiators or visible heating systems. This allows you to arrange a room without constraints and put furniture, curtains, doors and windows wherever you like.
  • Underfloor heating for energy savings
Underfloor heating is a low-temperature heating system. Whereas radiators heat to a temperature of 50°C to 70°C, the water flowing through a hydronic underfloor heating system is just 40°, delivering heat in the floor at a maximum of 28°C. This cuts down on the energy consumption and enables substantial savings on heating. What's more, when paired with a condensing boiler or heat pump, underfloor heating significantly increases the energy savings made.
  • A hassle-free heating system
Installing underfloor heating also has other practical advantages: not only does the absence of radiators prevent dust deposits, radiating heat from the floor doesn't circulate the air and allows you to breathe healthier air. What's more, underfloor heating doesn't cause vibrations or noise. Thanks to its insulating panels underneath the floor covering and screed, you'll forget that underfloor heating is even there.
  • Easier installation
Although installing underfloor heating used to be complicated due to the size of the system, recent innovations mean that the floor thickness is just 6 cm. Although fitting hydronic underfloor heating is still fairly technical, installing electric underfloor heating is simple, fast and well-suited to renovation work. What's more, a large number of different floor coverings can be laid over the screed of an underfloor heating system: tiling, natural stone, PVC, carpet or ready-made parquet, provided that its compatibility is checked in the "unified technical documents" ("DTU", specifications that govern the correct installation of renovation work).
  • Adaptability to all energy types
Underfloor heating is compatible with all types of heating energy: electrical power, domestic oil, natural gas, propane, wood pellets, solar power, electric or gas heat pump, etc. The heating can therefore be adapted to any type of existing system.

It's also worth knowing that you can install "reversible" underfloor heating, which as well as delivering heat in the winter also cools down a room when the weather gets warm.

The drawbacks of underfloor heating

Despite its benefits, like any heating system underfloor heating also has its disadvantages.
  • Underfloor heating is expensive
Having underfloor heating fitted requires a significant investment. The materials and installation are expensive, and only professionals who specialise in installing underfloor heating can carry out the work. Underfloor heating isn't eligible for France's energy transition tax credit, although the connection and regulation equipment may be and other subsidies exist for cutting the cost of your heating installation. Contact the French national housing improvement agency (ANAH) for more information.
  • Compatibility of the materials
Although extremely adaptable, underfloor heating isn't compatible with all floor coverings. For risk-free comfort, heat distribution and use, avoid excessively thick wood floors and beech or maple, which may become warped by the heat. You should also avoid very thick carpets and insulating mats, and ensure that the materials and adhesives of the coverings laid over the underfloor heating are suitable for this purpose.
  • Installing underfloor heating
Underfloor heating inevitably raises the floor by several centimetres. Although this isn't a problem in new builds, it may be an issue if you're renovating. Because this extra thickness in the floor isn't an original feature, it can hamper the opening of doors and windows or interfere with low elements (pipework, woodwork, etc.). It's also impossible to retain the original floors if this type of renovation work is carried out.

What's more, fitting this type of system takes time, meaning that the rooms can't be occupied while it's being installed. The amount of time it takes to lay, cast and dry the screed can't be reduced.
  • Access difficulties
If there's a technical problem, it's more difficult to service than with a traditional system that has accessible radiators. Indeed, it's difficult to perform repairs or adjustments to underfloor heating because this floor heating is invisible and covered with screed.
  • Inertia and heating time
In some cases, underfloor heating can also pose specific problems. For example, the temperature partly depends on the surface area of the room being heated. If the room is too small, the system won't perform very well and the comfort temperature may not be reached. If it's a bathroom, this lack of heat can nevertheless easily be made up for by installing a towel warmer, which will raise the temperature of the room by a few degrees.

What's different about underfloor heating is that it's also inert. This means that after it starts it takes a certain amount of time for the entire surface of the screed to heat and for the desired temperature to be reached in the room. This type of heating therefore isn't suitable if you need periodic or more dynamic heating that's effective more quickly.

This inertia phenomenon sometimes causes overheating if the heat from underfloor heating is combined with other heat sources such as the sun, household appliances, etc.

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