Retrofit underfloor heating - calculation of the costs per m²
- Costs and prices for underfloor heating
- Different systems - different costs
- Subsequent to installing a floor heating system
- Models for retrofitting
- Complete system for underfloor heating
- Thin-film process and electric underfloor heating
- Electric underfloor heating - costs
- Disadvantages of underfloor heating
In the new building, a floor heating system is often installed today. In the old building it is a bit more expensive to also enjoy warm feet on the floor. Of course, the costs are quite different. Here is a calculation of the approximate costs that may be incurred per square meter if you retrofit underfloor heating.
How much the retrofitting of the underfloor heating actually costs, also depends on the situation. If, for example, the floor has to be completely rebuilt and a new insulation installed, the costs for the subsequently installed underfloor heating increase significantly. If the floor heating is to be installed on an old screed, there are new systems that have a very low installation height. Although these are sometimes more expensive, but reduce the effort. So here again a part of the costs is compensated. Under certain circumstances, you can even save heating costs with the underfloor heating, because in an old building, the arrangement of conventional radiators is not always optimal.
Costs and prices for underfloor heating
The cost of retrofitted floor heating in an old building depends not only on the conditions of the old flooring, but also on the size of the rooms. The larger the number of square meters that should be equipped with underfloor heating, the lower the price per square meter. Of course, this is partly due to the connection costs to the previous heating system and various other aspects. In addition, the amount of cost per square meter depends on your own contribution. If you are prepared to remove the existing floor yourself or to glue the studded panels for a new floor covering yourself, the costs will be considerably reduced.
Aspects of costing - these questions should be asked:
- Texture of the floor and insulation under it.
- Approximate year of construction of the building "> Different systems - different costs
Even with underfloor heating, it is again important that you compare the offers of different providers. Even if you want to install the floor heating yourself, you should still ask the prices of local craft companies. Sometimes these are at almost the same level as the prices you already have to pay for the materials alone. Then, because of the company's warranty, it may ultimately be cheaper than doing the work yourself.
- Wet laying in the screed - construction height from six centimeters - per m² from 45 euros
- extremely flat floor heating system - construction height about two centimeters - per m² 80 - 120 euros
- electric underfloor heating - construction height about one to two centimeters - per m² from 40 euros
The costs also depend on the type of installation. Here you have the choice between a meandering and a helical installation. Detailed information about the construction of a floor heating can be found in our article "Structure of a floor heating" .
Subsequent to installing a floor heating system
If an underfloor heating system is subsequently installed, there is not always the possibility of classic installation in the screed. This method is also referred to as wet laying, since the heating coils for the surface heating systems are embedded in the wet screed. As the screed then firmly encloses the heating coils, the entire screed heats over the entire surface, which allows a pleasant even heat release. However, since this structure fails about six to ten centimeters high, the installation in an old building is usually only possible if the old screed is completely torn out.
Construction height of the underfloor heating:
- Wet laying directly in the screed
- between 6 and 10 centimeters
- Thin-film laying on the old floor covering / also on tiles
- between 2 and 5 centimeters
- Electric underfloor heating / also on tiles
- from 1 cm construction height
Models for retrofitting
There are some newly developed systems, which were developed especially for the subsequent installation of a floor heating in the old building. These often have a very low construction height, but possibly also a higher price per square meter. Suitable for retrofitting are so-called thin - film systems, which occupy less space with an installation height of two to five centimeters. In addition, there are still systems that are powered by electricity and therefore do not require any connection to an existing heating system. These are usually drying systems where no water runs through the heating coils. However, the follow-up costs are significantly higher here, since the power consumption of these electric underfloor heating systems can be very high. Positive, however, is the extremely low height of this floor heating, which makes it possible to get warm feet even in very low rooms.
Tip: These electric heaters are therefore more for a single room, such as the bathroom. Here, the underfloor heating is rarely used for the heating of the entire room, which further relativizes the heating costs.
Complete system for underfloor heating
In any case, you should purchase a heating system from one source. For most systems, heating is difficult or impossible to access later. If defects or leaks occur, a complete system made by just one manufacturer will make it easier to claim these defects. In the case of piecemeal components, leaks and problems occur more frequently, since the elements are not perfectly matched to one another.
Thin-film process and electric underfloor heating
Underfloor heating, which is laid using the thin-film process or as an electric heater, can be laid relatively easily on the old screed floor. Even the tiles on the floor do not necessarily have to be pricked out. If you do not disturb the additional height of the old tiles, you can stick a thin knobbed plate into which the heating pipes are then clipped. Then a potting compound is applied, which forms the new floor. The electric version is even thinner and is often simply glued on as a finished mat.
Electric underfloor heating - costs
Calculate the electricity costs for your electric underfloor heating in advance on the basis of the current electricity prices. If you only want to lay the heater in a small room, make sure that you only install it in the running area. Under the bathroom furniture, for example, you certainly need no heating. Most electric floor heating systems require about 100 to 180 watts per square meter. If the heating is then switched on for about an hour only in the morning and in the evening, you will consume about nine kilowatt hours per square meter per month if you use 150 watts as a basis. These costs can be tolerated even when, for example, three square feet of underfloor heating in a bathroom still well, if the feet are warm for it.
Detailed information on the acquisition and operating costs of an electric underfloor heating can be found in our article "Electric underfloor heating - costs and electricity consumption" .
Tip: As you can see in this small sample calculation, however, the electric heater for a living room of perhaps 30 square meters quickly becomes unprofitable. The heating time is much longer there and the electric underfloor heating would have to run almost around the clock to keep the temperature in the room. Only 20 square meters of heating surface then cause a power consumption of 900 kilowatt hours per month with a heating time of only ten hours per day.
Disadvantages of underfloor heating
Of course, such subsequent construction also have slight disadvantages. Since the old screed is not removed, there is no way to install additional floor insulation. But this is usually poor especially in old buildings. So it may happen that the new floor heating can not reach the desired temperatures in the room. This is important not only with regard to the comfort temperature, but also with regard to the energy consumption. Often therefore additional radiators are necessary in a real old building.
Please also read the article "Underfloor heating - advantages and disadvantages"