Underfloor heating system: which pipe to use

An underfloor heating system allows to achieve significantly higher living comfort than traditional systems by exploiting the principle of heat exchange by radiation.

Credits are distributed equally between design, materials used and installation: workmanship to the highest standard optimizes the qualities of an innovative and customizable system such as Valu-technik. A winning combination also confirmed in the installation by Giuseppe Vitrò, Aquatechnik Qualified Installer, with supplies from Mannella Group s.r.l.

At a private home in the province of Vibo Valentia, our radiant panel system was used. In detail: 15 cm shape distance in all areas to be heated, with the exception of the bathroom, with a 5 cm shape distance. For regulation, Valurapid manifolds with Safety fittings were used.

How does a radiant underfloor heating system work?

Radiant panel heating was born around the 1950s-60s, with several limitations due to a design and technology that had not yet evolved as much as today’s. The principle on which this type of system is based is as follows: hydronic floor heating uses low-temperature heated water flowing through pipes installed under the floor. The heated surface thus functions as an exchanger, heating the room in which people are located.

There are four types of heating, corresponding to as many methods of heat exchange: convection, conduction, radiation and evaporation. 

• Convective systems are based on a fluid -usually air- that is moved from one location to another by a mechanical means, usually a fan coil unit. In a hydronic system, air is replaced by water, which moves heat energy from the boiler to the radiant zone.
• Conductive transfer occurs when two objects of different temperatures come into contact. The hotter object transmits heat energy to the colder object across the contact area. In a radiant system, conduction occurs wherever the radiant pipe is in contact with the floor.
• Radiant transfer occurs when a hotter object releases energy to a colder object via energy waves, without contact. In the case of the radiant heating system, the exchange of heat particles unifies and balances the temperature of the two bodies in question.
• Evaporation is the heat exchange that distinguishes biological organisms. It occurs through the cessation of heat to the air by evaporation from respiration and/or sweating.

Traditional radiator heating systems, particularly air heating systems, have heat exchange by convection, while radiant panel systems operate on the principle of heat exchange by radiation and, to a small part, by convection and conduction.

Excellent comfort levels with Valu-technik radiant systems

Radiant panel systems optimize all the conditions necessary for the physiological well-being of people in every season: air temperature, surfaces in contact with the individual, air movement in the room, and humidity.

In winter version, with the heating function, the use of radiant panels creates an equal temperature situation in the rooms by eliminating the turbulence factor and significantly limiting heat loss, typical phenomena of radiator systems. Even in the cooling function, temperature distribution is uniform, resulting in a lowering of temperature on surrounding surfaces. The concomitant action of the combined dehumidifiers also optimizes the degree of humidity in the air, eliminating the condensation effect.

Other advantages of Valu-technik relate to safety: as underfloor heating does not require wall heaters, it avoids any kind of possible impact and damage against them.  It also creates a healthy environment, as it does not emit air currents that can raise dust and allergens. Thanks to the control of humidity levels, the formation of mould and condensation is also a factor overcome.

Installation benefits and complete components

The ways in which an underfloor heating and cooling system is designed provide additional benefits: on an aesthetic and space level, the absence of radiators allows rooms to be better utilized and leaves the way clear for design, avoiding the blackening of walls by radiators. Space is also made for the specific needs of the installer, thanks to Valu-technik system components ranging from insulation panels to expansion joints and multilayer pipes, as well as a range of accessories that complete the material required for  installation.

Aquatechnik’s wide range of insulation panels, produced in compliance with current regulations, meet various technical requirements with a minimum thickness from 10 to 42 mm: thermoformed and preformed panels, flat, with shapes in relief, with and without sound insulation, with and without HD polystyrene protective film. The task of panels is fundamental, as is their selection: they support and fix the pipe and contribute significantly to the thermal insulation of the slab, as well as to energy saving since they prevent leakage.

Together with thermal insulating skirting board, screed additives, synthetic fibres and fixing clips, the Valurapid modular manifolds complete the supply: they ARE available in both single and pre-assembled versions (diameter 32 or 26 mm – outlet 16 or 20 mm, with safety or eurocone connection, with holder, gasket or flowmeter). Climarapid, on the other hand, is the range of manifolds with a mixing unit that allows simultaneous management of a high temperature circuit and a low temperature circuit. Each kit has from 4 to 12 connections in low temperature and 2 in high temperature.

All Valu-technik components are adapted to the building site, facilitating laying and installation. An advantage also recognized by installer Giuseppe Vitò who appreciated ‘the speed and ease of installation, pluses that come to the aid of the installer’s needs!’.

Underfloor installation: choosing the pipe

Among the elements that contribute to the optimal installation and thus operation of an underfloor heating and cooling system are undoubtedly the pipes.

Pipes convey the system’s heat transfer fluid and must have specific mechanical characteristics in order to be durable and allow the system to perform efficiently. First of all, they must have a high resistance to thermal shock, that is, they must be able to withstand sudden, high changes in temperature without change in operation. In this regard, PE-X/AI/PE-X Multi-calor multilayer pipes are undoubtedly an excellent answer due to their high breaking strength: the guaranteed product life is 50 years with use at pressures of 10 bar and temperatures up to 95°C, or higher pressures with temperatures below 95°C. Failure can only occur when pressures exceed 100 bar.

Conductivity of 0.42 W/mK is another important requirement to facilitate the leakage of fluid heat to the outside, so as to avoid thermal obstacles in the exchange and not to compromise the overall performance of the system. Another type of resistance that is indispensable is the one to corrosion and chemicals, which will be used to clean the systems. Due to their polymeric nature, the materials used for Valu-technik system multilayer pipes are free from corrosive phenomena typical of metals. In addition, their exceptional resistance to major chemical compounds allows them to be used in various applications, including industrial ones.

The flexibility of Aquatechnik’s multilayer pipes, such as Multi-calor, is another advantage that amazed the installer: they are extremely light compared to metal pipes, generally weighing only a quarter as much as a copper pipe and a fifth as much as an equivalent steel pipe. Furthermore, thanks to the combination of cross-linked polyethylene and aluminium, these pipes offer high flexibility during bending, which is maintained even after the pipe has been shaped. This type of pipe maintains its configuration over time, which reduces the number of bracket clips needed compared to other plastic materials used in systems, such as single PE-X, PE-RT, PP-R, PB, PVC-C and others.

It is therefore clear that a multilayer polypropylene and aluminium pipe is the best choice for a radiant panel heating and cooling system due to the intrinsic characteristics of the material and also related to Aquatechnik’s specific proposal compared to traditional materials, such as copper, which is more expensive and more difficult to lay and work with.

Which diameter to choose for the multilayer pipe in the radiant system

For a professional installation, it is essential to select not only the best materials, but also to evaluate the most suitable diameter of the multilayer pipe that will be used. Multi-calor, Multi-eco and Polipert pipes are available in rolls of various lengths in diameters from 16 mm to 20 mm.

The use of 16 mm piping allows an ideal compromise between pressure loss and optimization of the number of circuits required.

In industrial applications, on the other hand, the large areas available, allow for laying with larger wheelbases, therefore making it possible to use 20 mm diameter piping, which would otherwise be difficult to handle.

The efficiency of radiant panels also for the environment

The benefits of a radiant panel system do not stop at installation and living comfort, but go further: efficiency and savings are other strengths of Valu-technik.

Radiant underfloor heating is easy to use because it can be controlled with a thermostat. Temperature and time can be controlled at the push of a button and are also compatible with Wi-Fi smart thermostats, which increases not only its ease of use but also its efficiency because it saves on the energy used. Underfloor heating systems also require a lower operating temperature than radiator systems (30°-40°C vs. 70°C). This allows ideal pairing with generators such as heat pumps or condensing boilers whose high efficiency helps reduce costs in bills. On average, radiant underfloor heating systems allow savings of 15% or more.

Another advantage? They require no maintenance to reduce this type of cost as well. In short, Valu-technik is a win-win solution for both end consumers and installers.