DIY: Lay and connect electric underfloor heating

• Basic information about installation
  • Properties of electric underfloor heating
  • Substrate treatment before installation
  • Special features in wet rooms
  • Special features of wood substrates
• DIY instructions in 8 steps
• The thermostat
• frequently asked Questions
• The different subfloor coverings
• The flooring

The electric underfloor heating ensures a pleasant warmth, which is distributed evenly throughout the room. In winter you always keep warm feet and benefit from the individual adjustment options. But how is the heating professionally laid and what points do you have to pay attention to at work? "

The heating of premises is an important issue, be it in new construction or modernization. Electric underfloor heating increases living comfort while increasing the value of the building. It has numerous advantages when laying over other types of heating, as it is implemented quickly and easily with little effort. It is important to pay attention to the correct connection to ensure safety and proper function. After laying a floor covering can be applied, here are also some points to note. Other factors include insulation and insulation.

Basic information about installation

The underfloor heating can be installed both in the new building and subsequently. The retrofitting is possible in the old building as well as the prefabricated house. With a little manual skill can save the cost of a specialist company. If you are unfamiliar with electrical installations, you can also do the laying yourself and commission a specialist company for commissioning. If the connection is carried out yourself, then carry out a check before commissioning and if necessary have the heater removed by a specialist company.

Properties of electric underfloor heating

Basically, you can use underfloor heating under any flooring. Electrical variants have only a small height, so that simplifies the installation. If the old floor coverings are sustainable, then these can be reused. When retrofitting, it is important to prepare the soil beforehand. If it serves as the basis for the underfloor heating, then an underground treatment must be carried out. Damaged surfaces are not suitable and must be replaced if necessary. Often, however, a repair is possible.

Substrate treatment before installation

To be able to use the floor, you must perform the following steps:

• First remove all old flooring residue and loose parts that would prevent a flat surface.
• If there are any bumps and holes in the floor, you must fill these. Then level and smooth the floor, for example by sanding. Overhanging remains must be removed.
• Apply a primer. This step is used for surface sealing and ensures the carrying capacity.
• If necessary, seal the floor against moisture.
• To avoid heat loss, it is an advantage to install an insulation.
• Before starting the actual laying you have to clean the floor and let it dry sufficiently. He must be dust-free in any case.

The laying material is also subject to some requirements. Thus, the materials must not be heat-resistant or absorbent. Also check that the ingredients meet these criteria. For example, primers, tile adhesive, leveling compound and grout are crucial. If the materials are not heat resistant, they may deform, peel off or be destroyed.

Special features in wet rooms

Wet rooms, such as bathrooms or sanitary rooms, often require additional moisture protection. If you are planning a tiling made of ceramic, then in any case a composite seal should take place. Failure to provide adequate shielding may result in damage and fire hazard. If moisture penetrates into the system, a complete replacement of the heating is generally necessary.

Special features of wood substrates

If you want to apply wooden planks, chipboards or similar coverings, then you must pay attention to the rear ventilation of the wooden floor and implement them accordingly. Socket profiles prevent the formation and infestation of moisture.

DIY instructions in 8 steps

Step 1: Create a plan

The heating should always be laid according to a plan. This will ensure that you get the best thermal effect. Measure all room dimensions and transfer them to a true-to-scale plan. Afterwards you mark the places for the furniture.

This will identify the furniture zones and have a layout plan at hand. This procedure is important to prevent heat accumulation and damage to the heater. If furniture prevented the heat dissipation of the heating, then it would come to the congestion of heat. The inventory can heat up, floor coverings are destroyed and underfloor heating can be damaged. In addition, the risk of fire would increase. Before laying the heating, you must also specify the position of the temperature sensor and enter it in the plan.

Step 2: Calculate the demand for heating foils or heating mats

Once you have determined the laying area and entered it on the plan, then you must determine the number and dimensions of the heating mats. If required, the heating mats can be folded over at non-live points and thus adjusted. In any case, pay attention to safety and avoid obstruction of live areas. Heating foils are cut to size and can therefore be adapted to the circumstances.

Step 3: Add necessary points to the plan

Include all relevant factors in the plan, such as probe sleeves, isolation points, plumbing pipes and connecting cables.

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Step 4: Prepare the heating foil or the heating mats according to the set up plan.

Step 5: Lay the foil or mats on the prepared surface.

Tip: If you retrofit the heating in the bathroom and use it as tile heating, you can also lay the heating elements in tile adhesive. Make sure that the conductors are completely covered with either a leveling compound or the adhesive.

When retrofitting with foils, roll them out and fix them. The heating foils can be self-adhesive or have the possibility to staple. Before laying the laminate, PVC or parquet, laminate the pipes with aluminum foil.

Step 6: Allow the leveling compounds to dry completely. Make sure you have sufficient insulation before.

Step 7: Lay the flooring over the heater.

Step 8: Next you need to connect the heater. It is important to observe the manufacturer's instructions. Oftentimes, a prolonged warranty / guarantee is granted in the case of an installation carried out by a specialist company, or the liability is excluded in the case of a self-constructed installation. Whether this is legally permissible, is questionable, however, avoid later trouble with the manufacturer, if you consult a specialist at least for a check or acceptance. In any case, have this measure confirmed in writing, for example by listing it on the invoice.

Important: In order to ensure perfect function and safety, it is important to check the correct installation. Always use an ohmmeter and measure the resistance of the heating mat. Compare the measurement results with the manufacturer's specifications.

The thermostat

When you select the location for the thermostat, there are a few things to keep in mind:

• Place the thermostat at least 50 cm away from exterior doors and windows. This is important because opening the windows and doors changes the temperature.
• Avoid a location on the wall that is exposed to direct sunlight. The inside of an outer wall is also not suitable.
• In the bathroom, the thermostat must be placed on a flat surface. Observe the local building regulations during installation and connection.

frequently asked Questions

What do I have to consider with the electrical lines ">

Tip: If you apply for a heating tariff for your energy supply, you have the option of saving on the electricity bill. However, there are often structural requirements for this. Inform yourself in advance about the conditions, so you save yourself expensive retrofits or high electricity bills.

What do I do during installation when there is an obstacle in the way?

If you install and connect the underfloor heating, obstacles may emerge that have to be bypassed. In this case, you can cut the net of the heating mat under the cable.

Important: Never cut or damage the cable. Then continue the heating mat in the new direction. For the floor sensor of the thermostat, you can mill a suitable slot.

Important: You must cover the connections between the power cords and the yellow heating cable.

What do I have to consider when selecting the floor coverings "> The different underfloor coverings

Screed: screed is suitable for underfloor heating. However, a primer is necessary. When laying, pay attention to expansion joints and edge joints.

Gypsum boards and dry screed: Other materials are suitable in principle, but it depends on the information provided by the manufacturer. In individual cases, the soil may be unsuitable. The reason lies in the different temperature resistances of the material. Please note the manufacturer's instructions for the plaster. Only if this can withstand the high temperatures of the electric underfloor heating, the use is possible.

OSB boards and chipboard: With sufficient strength, both floor variants are suitable. Make sure that the base is resistant to treading and not swinging. A primer is an advantage.

Raw concrete: Raw concrete should only be used with sufficient insulation. Otherwise, it comes to a large heat loss.

Asphaltstrich: Also in this case you have to pay attention to the temperature resistance. Especially older screeds could deform.

The flooring

Laminate, cork and parquet

If you decide for parquet, cork and laminate, then the heating capacity must not be too high. The heating power should be between 50 and 140 watts per m². Under laminate, cork and parquet you can lay both heating foils and heating mats.

It is recommended to lay the electric heater on a footfall sound insulation. Also pay attention to the temperature resistance of the materials. Lay heating mats in the leveling compound, fill everything and wrap the components in aluminum foil.

Carpeting and PVC

Above all, the heat resistance of the underside of the floor coverings is crucial. There are some major differences between the individual models. In this case too, lay the heating cables first in the leveling compound and then level them. Heating foils are often the simpler variant.

The heating power must be selected depending on the heat resistance of the underside of the lining. Note that carpeting leads to a strong insulation and shields the heat. As a result, the bottom of the bottom heats up more than other floor coverings. For this reason, the heating power must be matched to both the coating, the texture and the strength.

Granite, marble, tiles

Tiles have a rather sluggish behavior in heat absorption and heat dissipation. Therefore, it is recommended in this case to select a higher heating capacity. The heat output is expressed in watts, more precisely in watts per m².

Especially in the bathroom tiles are often used. This will make the floor in the bathroom pleasantly warm after showering. Whether in the bathroom or in the living room, with tiles, marble and granite and stone floors, the heat is difficult to get through the material, so that in this case the heating power must be higher. In general, outputs of 160 watts per m² are optimal.

In any case, check the heat permeability. The heat resistance is usually not problematic because it is usually sufficiently high. Information on the maximum thickness of the floor to be laid can often be found in the manufacturer's instructions for electric underfloor heating.

Tips for quick readers:

• You can use heating mats or heating foils
• the substrate must be suitable.
• pay attention to heat resistance
• for tiles, marble, granite, stone floors, observe heat permeability
• Adjust heat output to material
  • Tiles, marble and granite and stone floors: higher heat output
  • Wooden floor, laminate, parquet, cork: lower heating power
• Prepare underground
• possibly prime
• Floor must be level
• Measure the heating mat resistance after laying
• After connecting, have it removed by a specialist company