Top 15 disadvantages of underfloor heating

underfloor heating system

I have done extensive Google searches to gather as many opinions as possible about the disadvantages of underfloor heating systems. From my point of view most of the arguments of those who are against the underfloor heating systems are myths.

These myths appeared due to the fact that there was little information in the field and many works or executed without design and without specialized training. That is why there were many heating systems under the floor with water that did not work or did not work at optimal parameters.

But the trend is favorable for underfloor heating systems, systems that will be increasingly popular especially in combination with insulated houses and condensing heaters or heat pumps.

If you have decided to do a floor heating, you better buy a floor heating project to get rid of worries and complications.

Is underfloor heating healthy?

Yes, this legitimate question is often asked, regarding the underfloor heating. Underfloor heating is subject to rules of maximum radiant surface temperature. If we exceed this temperature, the floor may cause discomfort in the first place and may cause health problems, but there are no in-depth clinical studies on this topic. As long as we are within the allowed limits, underfloor heating is healthy.

Does the underfloor heating system raise dust?

“One of the disadvantages of this heating system is the fact that it can lift the dust from the room faster than the classic radiator systems, because it heats up a large part of the floor, which is also one of the reasons why the Nordic people use it mainly in rooms with high humidity. ”

“At least for me, even if the floor temperature is low, keep the dust up. I made comparisons with the other rooms and I can say that there is more air dust in the areas where I have the floor. For asthmatics or those with allergies it is not a very interesting thing. I have heard many complaints about this. The good part is that the dust is evenly distributed ”

“It was not recommended for homes due to the fact that the dust is high due to the heat from the floor and the rate of lung disease was higher for those who had this type of heating compared to those with heating by radiators …”

“Whoever says that underfloor heating does not rise honestly, I do not think he knows exactly what he is talking about, I have not only my experience but also other friends who have this heating system installed. The dust stays uuuuup and stays there. If you want, on a sunny day take pictures in rooms heated on the floor and in those with radiators. It can be said that it does not circulate as much as in radiators but only that.

The dust issue seemed to me to be one of the most frequent fears of potential users. In fact, underfloor heating does not produce dust.

Dust exists almost everywhere, if the level of dust is visible means that we must identify the cause of its appearance.

Even if we change the heating system this does not help to eliminate dust. The dust will rise and if we train it by moving in the room.

Against the dust we must consider the following: the cheapest option is to clean more often, to remove all residues after construction and finishing, to aspirate the dig before the installation of the parquet, to install centralized suction systems with external drainage, to install systems for ventilation with F7 or F9 filters, to keep the house under pressure, we can have portable filtration systems inside.

Does underfloor heating dry the air?

“Underfloor heating … not much is done. Dry the air plus other disadvantages. ”

Someone was saying that the air is not as dry. “When I had young children I bought a hygrometer (it measures humidity) to be sure I don’t have problems with humidity. Now it is mounted in the kitchen where it is assumed that I have a relative humidity higher than in the other rooms. Unfortunately it is not so as long as temperatures outside were positive and heating worked sporadically humidity was OK, about 55-60 %. Now when it’s cold and floor go more morning found 35% humidity. We measured and in the other rooms and the values ​​are close – 35-40 %. Not to be thrown in front of me again, that I built the installation with “nothing” [although I did it with a company something, I mention that it is completely automated, the temperatures in individually regulated rooms, the temperature on the boiler flow set to 50 degC and floor heating set to 27 degC ”

Our houses are not tight, they have quite a lot of infiltration and from time to time we ventilate. The phenomenon of decreasing relative humidity in houses as it cools off is normal.

The ability of the air to retain humidity decreases as the temperature decreases, so cold outside air with high relative humidity will have low relative humidity and will dilute the relative humidity in the house by lowering its percentage.

That is why in winter the ventilated houses have low relative humidity.

We can consider that any heating system acts on humidity as well.


Can the heating pipes be broken in the floor?

“Are there any risks that those pipes, no matter what they are, will break? Either from dilation, or from wear and tear … various reasons. And of course, if they break, will the hot water be in the house? ”

Serious pipes for underfloor heating test each batch of pipes. There is a very low probability of having problems with a pipe due to a manufacturing defect. All pipes marketed in Europe are tested for a standard life of 50 years at nominal temperature and pressure. The use of pipes below the nominal temperature extends their life.

Can the underfloor heating system burn or burn?

“Attention, however, the lower leg is sensitive. I do not recommend this thing to those with small children. if the spirals are not set (too close in some places), there may be warmer areas and a baby will fry over there. ”

To be able to withstand the temperature of the heat agent it should be over 65 degrees and you can have direct contact with it. The operating temperature for the floor heating agent is generally below 40 degrees. If a pipe breaks, it cannot splash, it is embedded in the screed. Temperatures exceeding 40 degrees above the radiant surface are almost impossible.

Does the underfloor heating cope with the low temperatures?

“I am not coping due to soil losses at -30. in warmer areas of Romania (constant kind would work) but in the mountains I do not recommend. a small radiator eventually masked and closed to the installation does not bother anyone. and preferably only downstairs, not upstairs. otherwise the warm air rising from below meets the ceiling already heated by the pipes and is bad. ”

The underfloor heating faces any suitable isolated house in Europe. In the last period it does not seem to me that in Europe the temperatures are very low for very long periods. In a hurry we are preparing for the greenhouse effect.


Does underfloor heating help the development of microorganisms and bacteria?

“Come on, I’m in the discussion now. Regarding the fact that this type of heating does not raise dust, does not “smoke the walls”, I wonder if anyone has studied (or is a relatively new system widely adopted in the world) if this heated floor is not very harmful in terms of of bacterial or microbial plaque (I am not good at medicine) considering that it has an optimum hot temperature for the development of these microorganisms or whatever. ”

For the development of bacteria, moisture is also needed, generally, under floor heating there are no conditions for moisture formation. The system dries the hole, evaporates even the water from the siphon. There may be this danger in the case of the man who also cools the rooms with the help of the radiant system. In these conditions we must take precautionary measures against condensation.

Do you cope with removing condensation from the windows?

“What would cause the dust to rise, mold on the ceiling (?!?”

“I just came from a girl who used to sell Junkers, and she advised me not to put myself on the floor, which is a good name for churches and halls … Look how losing the customer world …”

“Does the heating just face the floor without heaters? I refer mainly to the condensation on the windows. ”

The formation of condensation on the windows depends on the quality of the hardware used and the relative humidity in the house, not the type of heating system.

If the temperature of the inner surface of the insulation drops to the dew point, it will condense regardless of the heating system. Mold is also a problem of condensation, it is solved with thermal insulation and / or ventilation.

In general, the surface of the window reaches the dew point because there is a thermal bridge inside the hardware. A quality hardware will not reach the dew point.

How to repair the underfloor heating system?

“If something goes wrong, how do you repair it? to heaters is simple. ”

“If something is broken, underfloor heating, you beat it. At the classical one it is repaired very simply, or much simpler ”

It is very unlikely that a pipe under the floor will break in 50 years of operation due to a manufacturing defect.

Components that can fail in a floor heating system are visible components, which are extremely easy to replace.

And the distribution of flow to the radiators is also drawn by the floor. The use of a PPR type pipe for this operation is very risky.


What is the maximum step at which the heating pipes can be fitted to the floor with hot water?

“The dilemma is what is the maximum distance at which the pipes can be placed so as not to give you the feeling of being hotter and colder in an area.”

It is designed. But the maximum distance is 30 centimeters between the turns.


When are pipes from floor heating replaced?

“We can also assume that the pipes are of very good quality, but they will still crack in 5.6 – 10 years, when the problems will be the same – this will of course not happen if every 5-7 years a general cleaning will be done in the house, which will also include the complete replacement of the pipes, with all the tiles and the parquet above, which I think nobody does. ”

“The life of the heating system is 50 years. After 50 years what are you doing? In the conditions in which you have no “incidents” in the meantime.

Do you break everything and change the pipes? It’s pretty expensive for this fun. ”

The European norm obliges the producers of the pipe for heating in the floor to test the pipes for a period of use of minimum 50 years, under pressure and nominal temperature, but the life can be much longer and it depends on the temperature and the operating pressure.

Tests have shown that use with lower temperature and pressure prolongs the life of pipes. These pipes can last maybe even hundreds of years depending on the quality of the charging water in the installation.

How high is the thermal inertia when heating the floor?

“The thermal inertia is large to very large and with two faces. Until you heat the floor, all the possible frigures pass you by. Meanwhile in the other rooms the temperature is Ok, perfect I could say. The good part is that when the boiler is stopped for a few hours the floor does not cool significantly. ”

“The only thing I reproach myself with is that it has a high inertia and has to be kept running all the time. To recover a lost degree is difficult, 2 degrees is already a problem. The advantage that comes with this problem is that the temperature becomes uniform, constant and that at 21-22 grams I feel the same comfort that I had in the block at 23-24 degrees.

Yes, in fact, the underfloor heating systems have a great inertia. An efficient system reaches 80 % of capacity in 6 hours and 100 % in 24 hours. These systems must work permanently not in the open / off system.

Poorly executed systems can arrive in a week or never.

If we have an application where we want to quickly reheat a house, (for example, a holiday home) with only underfloor heating, it is not the best option.


What kind of liquid does the heating system load on the floor with a thermal agent?

“It is not recommended to circulate water in the underfloor heating system, but a special liquid. no more details are withheld. about the liquid explained to me the low degree of corrosion (low hardness of the liquid), the resistance to temp. negative if it happens to decrease temp. and not to start the installation (occasional residential building). otherwise services may appear and the customer pays ”

In the underfloor heating system and in all installations with thermal agent, the use of demineralized water with a conductivity below 100 microsiemens / cm is recommended. Avoid using antifreeze or other corrosion inhibitors.

What kind of flooring is the heating in the floor with water?

“Secondly, I am not convinced that the flooring system works so well with solid wood flooring. There is not so much history and experience in this regard.”

“The triple-laminated flooring is not very recommended for underfloor heating, there is the possibility of not resisting. It should be of good quality, possibly brought from outside (it is said that it is ‘boiled’ well), with a quality certificate and specific that it is good for underfloor heating (sometimes it has an H on the back, from the Heat) Then, being of a larger thickness it will have an insulating effect and probably the underfloor heating will not cope, and will have to be supplemented with radiators. ”

The underfloor heating systems can be used with solid wood flooring but also with any other type of flooring, this must be taken into account from the design of the installation.

Lately, I have seen that solid wood flooring is less and less used, is extremely expensive and requires extra special mounting conditions.

Solid wood flooring for underfloor heating is less wide and is very sensitive to relative humidity. If we are unable to maintain a constant relative humidity, due to deformations, it can effectively remove the screed.

Can the underfloor heating system be placed under furniture without legs?

“If the sofas and cabinets do not have legs of course you will not put under them, but if you can put them quiet.”

“Another disadvantage is that in general in a room where there is a heating system in the floor you must know very well the location of the furniture since the design phase because it is not recommended for such systems to be positioned below it, thus losing Also in this chapter we can talk about the fact that the repositioning of the furniture if it is desired to remodel the room must be done with great care also to avoid losing the efficiency of the system.

Moreover, the furniture must have legs in order not to be in direct contact with the floor, especially in the area where the heating system is positioned and unfortunately you will not be able to use any carpets or carpets in those areas. ”

“Because the underfloor heating is fixed (you cannot move the pipes once you have poured the excavator) it becomes very difficult to rearrange a room (to start moving / changing furniture) at will. If I do a floor heating taking into account a furniture without legs (bedside tables, beds, siphons, etc.), theoretically, I will have to create a “layout” of pipes to bypass these pieces of furniture. If my wife beats me to change the furniture (this can happen every 10 years for example) I will be forced to go to the same arrangement of the furniture in the room. I will not be able to change the furniture from one wall to another because there will be unheated floor areas. ”

The underfloor heating is installed in the entire screed regardless of the furniture above, for several reasons but first of all, do not worry about choosing the furniture.

Does the underfloor heating system evaporate water from the drain trap?

“Considering the low prices of the last period we can not talk about it as a disadvantage. Only as an annotation I would add an added care to the installation of drainage in the bathroom, especially the floor siphon … because without paying attention to this detail .. it appears due to the temperature of the floor a feeling of discomfort due to the smell as a result of evaporation. Siphon water and I also recommend the use of quality tiles in the bathrooms that allow the use of anti-lime solutions, as whitish stains may appear on the tiles. Otherwise the dust issues I think are only legends … because we are not talking about convection heating but radiant, so the fear of dust in this case is similar to the salt drop. But I repeat it is only about properly designed and executed floor heating installations ”

The problem with the evaporation of water from the siphon is real, but for this there are siphons with trap to avoid the problem of unpleasant odors.


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