What is Underfloor Heating? Why is Underfloor Heating Important? What is the History and Advantages and Disadvantages of Underfloor Heating? How is Underfloor Heating Done?
- Oğuzhan ÇALIŞIR
- Oct 20, 2024
- 9 min read
Author: Dr. Eng. Oğuzhan ÇALIŞIR
What is Underfloor Heating? How Did It Develop Historically?
The floor heating system, in its simplest form, is the heating of the environment with hot pipes placed inside the floor. The main logic of the floor heating system is to increase the surface area, reduce the temperature difference and consume less energy and provide a more comfortable heat target. The heat in the pipes (water system) or cables (electrical system) placed in the floor areas is heated where the floor is operated (Figure-1). These systems have been widely used as an alternative to classical systems for years. The most natural use emerged in ancient times in Far Eastern countries and later in Rome with the heating of baths. The most common examples of bath heating are seen in Anatolia. Today's baths are widely used in structures such as residences, mosques, hangars, sports halls, etc.
Figure-1. Underfloor Heating System Working Principle
The Importance of Underfloor Heating
Since the 1970s in Europe, underfloor heating systems, which have been applied in both residential and industrial buildings, have become increasingly known and are emerging as a rising value.
Energy efficiency is currently becoming the state's energy policy. The essence of this policy is to prevent energy losses, use the efficiency of the existing amount and produce in a new efficient way. In question. Underfloor heating systems; It offers users the opportunity to use it productively.
When considered here, a saving and great return will be provided for the heating of 70%-75% of the total energy of the residences.
What are the advantages of underfloor heating?
Underfloor heating system saves energy
There are fundamental differences between underfloor heating and traditional parameters heat transfer rules. While the majority of heat transfer in radiator applications is carried out by convection, that is, by heating the air and storing it in the space; in underfloor heating systems, the majority of the transfer is radiated, that is, it ends with radiation (Figure-2). On the other hand, while the boiler water temperature should be exhausted to 70-80°C to provide suitable room temperature in cut-off systems, the underfloor heating boiler water temperature should be a maximum of 50°C, because in heating with cut-off, the temperature of the cut-off panels reaches up to 55-60°C, while the floor temperature for a heated feed during underfloor heating is 24-29°C. In radiator applications, the targeted space temperatures are 1-2°C higher than the targeted distance with the underfloor heating system due to the fact that the air is cooled and the comfort increase of the air movement is increased. This temperature should not be underestimated due to the annual 6-10% energy saving at different rates.
Figure-2. Radiation Heating in Underfloor Heating
Underfloor Heating Provides Comfortable Heating
It provides a comfortable environment thanks to the homogeneous distribution of temperatures in the space both in the extreme and vertical axis (Figure-3). Every part of the room is heated equally. Radiator operations are carried out; there is no problem of places close to the radiators being hot and places far away being cool. It is seen that the temperature data obtained in floor heating systems are much closer to the ideal distribution. With special collector systems and room thermostats, you can control your home as a whole, on a floor or room basis, according to your desire, and set the desired temperature values. With the timing module, the time temperatures decrease when you are not at home, and you can ensure that the space features reach the desired equipment before you return home.
Figure-3. Comfort in Underfloor Heating
Underfloor Heating is Environmentally Friendly
While underfloor heating applications provide energy savings thanks to the low temperatures in question, they can easily be combined with energy efficient systems that use cutting energy sources such as ground heat and solar energy. Renewable energy systems benefit from completely natural resources while allowing the user to distribute fossil fuels such as natural gas and diesel from price changes. They also contribute to the protection of eliminating carbon emissions.
Is Underfloor Heating Healthy? Does Underfloor Heating Create Dust?
The underfloor heating system is healthy. Underfloor heating does not create air movement during heating, where you have a 50% radiant (ignition) heating. This both positively affects human comfort and does not harm the layer of dust on the surface from rising, plastering, sticking to tulles and curtains and the ceiling and creating a dirty appearance. The reason for the dust flying in the space is the air flow in the environment. The reason for the air flow is the replacement of hot air and cold air in the space. In other words, the greater the temperature difference in the environment, the amount of flying dust will also increase. In the Underfloor Heating System, the temperature differences in the space will be much lower with the storage system and the counter values, and the possible dust will be less at this rate. As is known from daily life, the curtains of the windows included in the records are monitored. The reason for this is the air movements caused by the temperature difference between them and the environment (Figure-4).
Figure-4. Comparison of underfloor heating and cooling heating
Underfloor Heating is Aesthetic and Safe
Since underfloor heating systems are hidden under the floor, they allow spaces to be decorated as desired. It does not provide any space or volume, and it also saves time and money spent on maintaining unsightly components. The absence of protection panels that pose a risk of injury and accidents, especially for children, is an important advantage.
Does Underfloor Heating Cause Varicose Veins?
According to today's standards and if applied correctly, underfloor heating systems do not pose any harm to human health. TS EN 1264 limits the temperature of general areas in underfloor heating applications to 29ºC. Considering the average human body temperature of 37ºC and the foot temperature of 33ºC, it is not possible for a floor at 29ºC to cause dilation in the leg veins and cause varicose veins.
This kind of false prejudice occurs over time because people who do not have sufficient knowledge about underfloor heating systems and their applications use boilers made for cutting systems in the same way for underfloor heating, and the temperature on the floor is carried to very high levels (>37°C).
Applicable in high volume spaces Underfloor heating systems are extremely suitable for high volume spaces (mosques, churches, airports, lobbies, etc.) as they provide a homogeneous heat geography from the entire floor upwards and heat living spaces. Radiator applications will increase the negative effects of air movements on the ambient temperature in parallel with the increasing height and will create a significant disadvantage.
There are Many Different Application Options in Underfloor Heating Systems
Floor heating installations are available for wall or ceiling applications. Applications made on the wall have wet, spring application capabilities, as well as ready-made applications made in plates. Hamam heating starts from the floor and falls from the wall.
Applications on suspended ceilings are carried out with ready-made modules within the boundaries of suspended plasterboard panels.
Apart from this, other applications frequently used in the literature are industrial floor heating applied in places such as hangars, warehouses, factories, concrete temperature control system, grass field floor heating applied to stop the icing of football fields, open area floor heating and ice skating cooling.
What are the Disadvantages of Underfloor Heating?
Underfloor heating systems are low temperature heating systems (30-50ºC). Low temperature heating systems provide energy savings. In addition, since their initial protection is slow, they enter the late regime.
It would be a correct approach to operate the system continuously at a low setting without shutting down the capacity system with the underfloor heating system.
In addition, the underfloor heating temperature initial investment temperatures are slightly higher than the panel cooling heating systems. However, this difference is almost non-existent compared to aluminum protected heating systems.
How is or should underfloor heating be done?
The underfloor heating system should be done by expert teams like other heating systems. However, it is applied with a more professional application compared to other conventional heating systems. Because underfloor heating systems require a more complex programming method and more skillful application compared to other systems. In this case, in case of failure, extra care should be taken and the application should be done by unqualified companies and craftsmen. Below are the steps of professional underfloor heating system application in order.
Underfloor Heating System Project Design
Before starting the underfloor heating application, the first thing to do is to have the project drawn by professional engineers.
The work starts by requesting an architectural project from the customer in dwg format in a computer environment. After examining the incoming architectural project, the project owner is asked whether it can be added to the project later. The project is started based on any additional or architectural project. If there are any items to be added, it is continued accordingly. One of the most important questions to be asked in the previous versions of the project drawing is the collector locations. The location of the collector is very important. Because when the collector location is changed, the entire project will change, so this situation should be determined at the very beginning. The customer may not be informed about this. In this case, the project architecture or, if any, the interior architecture group can be asked about the collector location. In case no answer is received, the design engineer places the collector in the most reasonable place possible and makes the drawing accordingly. In Figure-6, a floor plan is applied with underfloor heating of an example villa project.
Figure-6. An example floor heating project
Pulling the Underfloor Heating Edge Band
The cost of the underfloor heating edge band is to ensure that the screed, which is heated and expanded like every other material after the screed is applied and the system is running, is removed. In this way, materials such as parquet, ceramic or natural stone on the floor are prevented from moving due to damage. The edge band also prevents the heat loss of the edge areas of the roof. There are two types, adhesive and non-adhesive, but there is no difference in terms of material content. Adhesive models are easier to stick and provide ease of application. Non-adhesive models are recorded with a cooling staple etc. There is no difference in the existence of both models. The edge band (Figure-7) should be applied to all walls of the place where heating will be done. It is a mistake that damages only the outer walls by cutting the material and there is no good in the result as it is thought.
Figure-7. Floor Heating Edge Insulation Band
Laying Underfloor Heating Styrofoam
The most important value of underfloor heating styrofoam is its density, i.e. density. Low-range styrofoams are both severely crushed and broken into pieces during installation. Styrofoams that are broken and crushed can use the pipe holding and flexibility feature. This means that an incorrect application is being made. This underfloor heating styrofoam must be at least 26 densities or 28-30 densities. High-density styrofoams are designed to allow easy installation of pipes and provide a homogeneous distribution on the floor. This product, which has a height of 40-45 mm, keeps your space warm and comfortable by helping to reduce heat loss to the lower floor. Its panel is approximately 60x100 or 60x120 cm in size and provides sufficient coverage for your heating facilities. Another important point to consider when installing styrofoam (Figure-8) is the leveling of the floor. Rough surfaces accumulated with screed, plaster, gypsum, etc. can cause high-density breakage and even breakage. From this point onwards, the previous floor should be heated with levelling screed and waited for it to dry sufficiently.
Figure-8. Floor Heating Styrofoam
Installation of Underfloor Heating Collector Cabinet
There are two different types of underfloor heating collector cabinets: under-concrete (Figure-9) or on-surface. The type that is concealed and concealed for liquids is used. However, if it is not possible to hide the record, surface-mounted cabinets can be used. The function of the collector cabinet is to mount the collector installation and at the same time to hide it. It also allows room thermostat switches to be mounted within itself. It is important for the cabinet door to be easily opened and to be made of as thick sheet metal as possible so that it is not crushed or damaged. It is important for the edge strip to be ergonomic in order to face the wall and to have an aesthetic appearance.
Figure-9. Floor Heating Collector Cabinet
Installation of Underfloor Heating Collector
The underfloor heating collector should be stainless steel and have a flow indicator (Figure-10). Chrome-plated brass and collectors without flow indicators used in radiator systems are not used in underfloor heating. Because after the system is put into operation and the water is based, which line has air and whether it is heated or not can only be determined with a collector with a flow indicator. Also, adjustment can be made in collectors with flow indicators. There should be automatic or manual air intake purges on the collector. Also, collector hanging clamps should be on the collector. If there are none, you can purchase them later and add them, but this will bring you an additional cost. Collector assembly can be done after cabinet assembly or as a final process. Because if the construction site is not well protected, collectors can get dirty or damaged.
Figure-10. Underfloor heating collector with stainless flow indicator
Installation of Pipe Connection Records
Underfloor heating pipe connection records (Figure-11) are the connection parts that provide the connection between the pipe and the collector. After the collector assembly, the pipe is connected to the record and the flooring system is started. If the collector is decided to be installed at the end, the records should be purchased last.
Figure-11. Pipe Connection Record
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