Underfloor heating is one of the alternative heating systems to traditional radiators, particularly widespread in new homes and designed to optimise energy savings. Its use has both strengths and weaknesses. Let's discover them together.

How does the underfloor heating system work?

Already used between the 50s and 70s, it has come back into vogue in recent years thanks to technological innovations that have improved its functioning, making it one of the most popular heating systems.

Underfloor heating systems have radiant systems that allow the heating flow through the surface radiation. They consist of:

• piping, adopted for closed circuit water heating;
• electric resistors for electrical systems.

In both cases, the pipes or electric cables are placed on radiant panels which are positioned under the flooring, thus being invisible. For this reason, underfloor heating can be an excellent aesthetic solution.

Operation is simple:

• with a piping system, it is crossed by hot water at a low temperature. Due to the radiation, the heat is distributed uniformly throughout the room;
• with an electrical system, the mechanism is identical, but it is electricity that acts as a heat transfer agent.

In particular for a water floor system, generally more widespread than the electric one, the elements for its correct functioning are:

• the pipes, made of polyethylene or a combination of plastic and metal;
• the insulating panels, designed for laying the pipes. They are generally impermeable to liquids or in any case protected with a sheet of plastic material to prevent the formation of humidity;
• the boiler or solar thermal panels to heat the water. As for the boiler, it can be powered by methane gas rather than LPG or be replaced entirely by a heat pump connected to the pipes;
• the manifolds and the regulating groups, essential accessory elements for the correct functioning of the system.

How convenient is underfloor heating?

The underfloor heating system is considered to get excellent domestic comfort thanks to the uniform heating diffusion.

It has many advantages.

• An underfloor heating system brings benefits in terms of energy consumption, with savings of up to 20/30%.
• The formation of dust and mites, which are very harmful to health, is avoided. It is so ideal for asthma and allergy sufferers.
• By not having to install radiators, space can be recovered in the rooms of the house.
• As seen previously, underfloor heating can be combined with a condensing boiler or a heat pump. Energy consumption is optimised even further, with saving on bill costs. The condensing boiler, for example, allows you to reuse the condensation generated by the exhaust fumes and transform it into other energy.

What is the best floor for underfloor heating?

The type of floor to be installed on the radiant panels plays an important role in obtaining the best energy results.

Two factors must be taken into consideration when choosing this element: thermal conductivity and thickness.

• Thermal conductivity: is the expression used to indicate the ability of a material to transmit heat.
• Thickness: if it is low, the thermal conductivity is higher and therefore the ability to transmit heat will be better. Choosing the right floor helps to optimise the performance of the entire heating system.

From this combination, it can be deduced which type of floor is best to use.

• The wooden or parquet floor does not have high thermal conductivity, even if its thickness is even a few millimetres. Its weak point is mainly represented by the fact that it is very delicate. However, considering that this technology can also be installed with this flooring, it is better to opt for stratified parquet or increase the number of coils of the underfloor system to give more calorific value.
• Granite and marble floors have good thermal conductivity, since they are two natural stones. On the other hand, the slabs have an average thickness of 2/3 cm, too much to ensure uniform heat diffusion.
• Conversely, porcelain stoneware or ceramic flooring is the ideal solution. Ceramic manages to heat up easily and transmits heat uniformly, opposing low thermal resistance. Thanks to this peculiarity, the heat is rapidly diffused in the environment. In addition, the final product has a very thin thickness while retaining strength.
• The solutions that can be adopted also include laminate and PVC floors. Their limited thickness lends itself to the crossing of heat and favours its diffusion.

What are the disadvantages of underfloor heating?

When evaluating the adoption of this heating system, the disadvantages must also be considered: first of all, the initial cost. Because if it is true that underfloor heating leads to savings in bills, it is equally true that its initial installation requires a considerable economic effort.

In most cases, for example, it requires the construction of a screed. The screed is a support layer of the floor which must resist mechanical stress and is necessary for:

• allowing a precise pavement levelling;
• receiving flooring;
• facilitating the loads’ distribution;
• covering the radiant system.

Underfloor heating is especially indicated for new buildings, which are nearing completion. This creates a new floor from scratch to facilitate the installation of the radiant system. It is necessary to proceed with the preparation of the base, intended to house the pipes rather than the electrical resistances and the special radiant panels.

On the other hand it is also true that an existing floor can be worked on, provided it is in good condition and therefore this is a hypothesis to be discarded with old floors.

The old cladding must be covered with insulating panels so that the heat does not disperse and is instead directed upwards. Once the system is installed, it must be covered with special solutions such as screed to have a suitable surface for laying the new floor.

An intervention on existing floors therefore involves raising their level which can impact on other elements present in a room, such as custom-made furniture for example.

Particular attention should also be paid to repairs in the event of breakdowns. They require the dismantling of the flooring and it is essential to rely on specialised technicians who know where to intervene promptly.

It is also important to remember that underfloor heating cannot be switched on or off intermittently. For the room to warm up, it must be left on for at least a day and must remain active even after having reached the desired temperature.

Furthermore, particular attention should be paid to the furniture that you plan to use in the rooms, especially the bathroom, such as carpets, sofas and furniture. All these elements hinder the heating of the rooms.