Warm feet & pleasant room climate – the properties of underfloor heating

The underfloor heating belongs to the surface heating systems and is differentiated into different models. On the one hand there are the electrical systems and on the other hand the hot water heating systems. The idea of heating rooms by means of a warm floor is not new, however, because even the Romans knew to appreciate these benefits. How are underfloor heating systems installed, how much do they cost and what are the real advantages and disadvantages of this heating system?

Underfloor heating – models, functionality & installation options

With hot water underfloor heating systems, heating coils are laid in or under the screed and this is usually done when the house is built. However, a subsequent installation of underfloor heating is also possible. One variant is electric underfloor heating, as it is installed as a network directly under the floor covering, but other alternatives are also available.

The models – wet and dry system & the electric underfloor heating system

Underfloor heating can be installed using the so-called wet system. For this, the heating pipes are laid above the insulation layer directly in the screed. The screed is poured around the pipes in liquid form, which also gives the system its name. The heating pipes are attached directly to the insulation layer or clamped onto laying plates. A wide variety of systems can now be purchased in the trade for this purpose, such as:

• Support element system
• Tacker system
• Clamping rail system
• Or the dimpled panel system

During construction, metal-containing additional particles are added to the screed so that the heat conduction in the floor is higher and the heat can be distributed evenly.

The dry system works, as the name suggests, without the need to pour a layer of screed. Here, the pipes are installed directly under the floor covering in foam boards and then covered with dry boards. This method is particularly suitable for retrofitting, as the system only requires a low installation height and no new screed needs to be poured.

With electric underfloor heating, the heating cables are laid directly under the floor covering. As this is fairly simple, installation can often be easily done by yourself and does not require a skilled expert. The system has a quick response time and provides heat faster than the other systems. Electric underfloor heating enjoys the additional advantage of not requiring any maintenance and consequently the cost is kept quite low. However, the disadvantage is that electric underfloor heating has higher operating costs.

Advantages and disadvantages of the hot water system

Even though the hot water system is mostly used only in new buildings, it is the most common. Even if it still differs in two different installation methods, the entire system offers many advantages and disadvantages that can be decisive in the decision. Especially for builders, a comparison of the most important points is useful to consolidate the decision-making process.

Advantages of a hot water system

• Operation with low temperature
  The hot water system is operated at low temperatures, for which a flow temperature of approx. 35 degrees is specified. The water therefore does not have to be heated strongly, whereby energy can be saved. The low temperature also makes a combination with renewable energies, such as a heat pump, possible.
• Warm feet throughout the house
  Especially in winter this advantage is a real luxury, because cosy warm feet in the whole house contribute enormously to the well-being and increase the cosiness.
• Individual room design
  When designing the room, there are more possibilities with underfloor heating, because no radiator, which must not be blocked by a piece of furniture, stands in a disturbing place.
• Pleasant radiant heat
  Underfloor heating works via radiant heat, because a full 2/3 of the heat given off by underfloor heating is radiant heat. This is generally perceived as very pleasant compared to the normal heat from radiators.
• Suitable for allergy sufferers
  The underfloor heating is particularly suitable for allergy sufferers and asthmatics, because no air is stirred up and therefore the dust concentration in the air is much lower. In addition, the air is less dry and more pleasant to breathe.
• Warm feeling at low room temperatures
  Due to the radiant heat and the regular distribution of heat in the room, lower room temperatures (about 2-3 degrees less) are perceived as warmer. The heating does not have to be set so high and heating costs are saved.
• Regular heat
  Since the heat is emitted from the entire floor surface and not just through a radiator in the room, the heat is distributed very regularly in the room and unpleasant draughts are avoided.

Disadvantages of a hot water system

• Adjustment of the room temperature
  In large rooms it takes time until the whole room has reached a certain temperature. Rapid heating up is therefore not possible with underfloor heating. Systems that are laid directly in the screed are more sluggish in terms of their ability to regulate. Temperature changes are therefore a longer process, as the room temperature adapts.
• Modification to the heating system
  After the fact, change the heating system is almost impossible. There are differences depending on the model, but especially the systems laid in the screed can no longer be removed.
• Installation and maintenance costs
  On average, underfloor heating costs a little more than the installation of an ordinary heating system. Here, however, it strongly depends on the model and the individual characteristics of the property.

Renovation & refurbishment – Retrofitting underfloor heating systems

Retrofitting underfloor heating is easier than you think, because modern techniques allow the heating pipes to be inserted into the hard screed. For this purpose, milling processes are used that mill the channels for the heating pipes into the existing screed. For renovations and redevelopments the underfloor heating offers, thus likewise an alternative to further heating systems. But what needs to be taken into account, where can the process be used and how powerful are the retrofitted underfloor heating systems really?

Old & new buildings – underfloor heating possible everywhere

Until now, the installation of underfloor heating during a renovation was almost impossible and was only conceivable with a new installation of the screed. Since the screed is rarely replaced during a renovation and a complete removal and re-laying is too complex and expensive, a new technique was developed to integrate the underfloor heating into existing screed. This technique can be used in all buildings, whether old or new. The advantages of underfloor heating can also be used in older buildings.

Installation – fast and low-dust despite milling technology

If the screed is fresh, the heating elements are laid first and then the screed is poured. But also the subsequent installation is simple. First the channels are milled and then the heating elements are laid and then the screed is filled in the remaining gaps. This technique maintains the height of the floor covering and doors do not have to be elaborately adjusted. Almost any screed, from dry screed to concrete, is suitable for the milling process. However, if milling does not work, dry screed boards can be used to help out. After drying out, the floor covering can be laid directly and the underfloor heating can be put into operation.

The risks – further costs and problems

If everything goes without problems, the subsequent installation of underfloor heating takes only one or two days and is quite inexpensive. However, the prerequisite for this must be, for example, that the screed is smooth and clean. Particularly in the case of renovation and refurbishment work, it can happen that the old floor covering cannot be completely removed or that other complications arise. Should this occur, you will have to reckon with additional costs for the smoothing and levelling of the floor.