How to choose a warm floor and install it correctly

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

The life hacker studied the popular heating system and put together a comprehensive guide with video for you.

What is underfloor heating

Underfloor heating is a heating system that does not require the usual radiators. The heating element can be an electric cable or water circulating through pipes. They are located over the entire floor area and evenly warm the room.

Heating occurs due to radiation, not convection. Heat spreads from bottom to top, which further increases heating efficiency. Hottest at floor level, colder at ceiling. This allows you to reduce the temperature in the room by 2 ° C, and the person's feeling of warmth will not change. Even such a slight decrease saves energy resources by 12%.

How the underfloor heating system works

Depending on the technology used, the device of underfloor heating is somewhat different, but in general, all types have a similar multi-layer structure. A layer of thermal insulation is placed on the floor or base, and heating elements are installed on it. Further, if necessary, a cement screed is equipped and the finishing floor covering is already laid on top.

Heating control in water-heated floors is carried out through a mixing unit. In electric ones, a thermostat is used for this, to which a temperature sensor located inside the floor is connected.

What are warm floors

By the type of heating element, underfloor heating is divided into water and electric. The latter can be made in the form of a cable, thermomat and film.

1. Water heated floor

At the heart of the underfloor heating water is a closed circuit of pipes with a circulating coolant, which is heated from the boiler and enters the system through the mixing unit. Due to the requirements for regulating the flow rate and temperature of the heating medium, this option is only suitable for private houses or apartments with individual heating.

Such floors are usually installed at the initial stage of construction. The base is waterproofed and covered with a layer of insulation, and then pipes are mounted on it, which are connected to the manifold cabinet and poured with concrete. Next, a finishing coating is laid on top of the screed.

Pros:

• The lowest operating costs.
• The most uniform heating over the entire area.
• Heating of the coolant is possible from different sources.

Minuses:

• The high cost of equipment compared to electric underfloor heating.
• Constructive complexity and laboriousness of installation.

2. Cable underfloor heating

A cable heating system is in many ways similar to a water heating system. The only difference is that instead of pipes with a coolant, a heating cable is laid in the floor array. It is powered from the electrical network and controlled by a thermostat that reads the readings from a temperature sensor inside the structure.

This type is installed during a major overhaul, since a concrete screed is needed. Thermal insulation is laid on the ceiling, a cable is laid out on top of it, then a screed 3-5 cm thick is poured and a decorative coating is mounted.

All electric floors, unlike water ones, do not have a self-regulation function and can be damaged by overheating. They must not be installed under wardrobes, kitchens and other furniture without legs. Therefore, the location of the furnishing elements must be thought out in advance and not changed.

The exception is the so-called smart systems, which are able to reduce power when the temperature of the heating element rises. However, they are significantly more expensive.

Pros:

• Low price.
• The ability to use in the apartment.
• Electrical connection without additional equipment.

Minuses:

• Relative complexity and laboriousness of installation.
• High power consumption.
• Cannot be installed under furniture without legs.

3. Thermomats

In fact, thermomats are a variation of the underfloor heating cable. The same cable is used here as a heating element, only of a much smaller cross-section and pre-fixed on a polymer mesh with large cells.

Often this type is chosen when finishing the floor with ceramic materials. With a thickness of less than 3 mm, the thermomats can be easily placed between the finished screed and the tile, taking up the space inside the tile adhesive layer. On sale there are thermomats with different cable spacing, designed for a certain power.

Pros:

• Ease of installation.
• Fast warm-up.
• Does not affect the thickness of the floor.

Minuses:

• High energy consumption.
• Cannot be installed under furniture without legs.

4. Foil underfloor heating

Film is another type of electric underfloor heating. Structurally, it is a conductive element laminated between two insulating polymer layers.

Installation of such a system is carried out on a heat-reflecting substrate. A warm floor is laid on top, and then a protective film. If linoleum or carpet is planned, then an intermediate layer of plywood is mounted. And the laminate can be laid directly on the foil.

Pros:

• Ease of installation.
• Almost does not affect the thickness of the floor.
• More energy efficient than cable floors and thermomats.

Minuses:

• Cannot be installed under furniture without legs.
• Not suitable for wet rooms.
• Easy to damage during installation.

Which warm floor to choose

In many ways, the choice of underfloor heating technology depends on the planned finish. It is important to take into account the specifics of the premises, the presence and material of the subfloor, as well as the possibility of arranging the screed. Well, you need to decide whether you want to replace the heating system or just supplement it.

• Water heated floor - ideal for a country house, even as the main heating. It will help you save money. It can be installed in all rooms and any coating can be used, but it must be installed at the initial stages of construction or renovation.
• Underfloor heating cable - an alternative to underfloor heating for apartments, although it can also be installed in private houses. Heating is possible, but expensive. Suitable for any premises, requires screed filling. The best coating is tiles; special laminate and linoleum are less suitable.
• Thermomats - an option for cases when it is impossible to make a screed. For the rest, everything is true for them as for a cable underfloor heating.
• Film warm floor - the easiest view to implement. Suitable for comfort heating, but not heating. Compatible with all types of coatings with high thermal conductivity and low thickness: laminate, linoleum, carpet.

Is it worth installing a warm floor yourself?

The installation of the system has a lot of nuances. Incorrect installation can lead to breakdowns or malfunctions of the equipment, and in the case of electric underfloor heating, also to a fire. Before proceeding with the installation, read the instructions and soberly assess your strength.

How to install a water heated floor

1. Install the manifold cabinet and place the mixing unit with the pump in it. Choose a place in the center of the house to reduce the length of the supply pipes of individual underfloor heating circuits.
2. Lead the main pipeline from the boiler to the cabinet. If you plan to install control automation, also lay the electrical cable.
3. Prepare the rough surface. Smooth out all drops of more than 5 mm, remove dust and cover the base with plastic wrap or other waterproofing.
4. Install damper tape around the perimeter of the walls to separate them from the floor slab and compensate for thermal expansion. The tape should be higher than the topcoat and cut after installation.
5. Place expanded polystyrene on the base, and on top of it mats with bosses or a net for fastening pipes. Lay out the pipes in steps according to the calculations. It is preferable to lay in a "snail" pattern, so that the supply and return pipes are close to each other for uniform heat transfer.
6. Connect the pipe ends of each circuit to the manifold. If necessary, install actuators to adjust the temperature with a room thermostat.
7. Close the taps in front of the mixing unit and check the assembled system for leaks with a pressure of 6 bar.
8. Without relieving pressure, pour a concrete screed at least 3 cm thick from the upper edge of the pipes. Wait 28 days for full hardening.
9. Install a decorative covering that is compatible with underfloor heating.

How to install cable underfloor heating

1. Check the cable resistance with a multimeter and make sure it matches the nameplate value.
2. Draw up a laying scheme, marking the location of furniture without legs and large-sized appliances, as well as indents from the walls by 5-10 cm. The wire does not fit into these places! Calculate the resulting area and make sure the selected cable is sized for it.
3. Install the back box for the thermostat and run the power cable into it. Make a pipe for laying the temperature sensor at a distance of 50 cm from the wall.
4. Prepare and clean the rough surface. If the underfloor heating is used for heating, lay expanded polystyrene on the base of the plate. If only for heating - a heat-insulating film. Glue the damper tape around the perimeter of the walls.
5. Attach a mesh or mounting tape to secure the cable and fold it out with a snake. A single-core wire is inserted into the junction box with two ends, a two-core wire - with one.
6. Insert the thermal sensor into the corrugation, put a plug on it and lay it into the prepared pipe.
7. Install the thermostat and connect the power and heating cable to it according to the diagram in the instructions. Turn on the system for a couple of minutes and make sure it warms up.
8. Turn off the power supply and fill the 3–5 cm thick screed with cement-sand mortar. Wait 28 days for the concrete to harden completely.
9. Install a topcoat compatible with underfloor heating.

How to install thermomats

1. Draw the installation scheme, excluding the space where furniture and large-sized appliances are located tightly to the floor. Provide indents from the walls by 5-10 cm. Depending on the resulting area, select a thermomat of suitable power.
2. Fit the box for the thermostat and run the power cable to it. Cut out the connector for the temperature sensor wire.
3. Clean the floor surface and prime the surface. Mark the area to be heated for laying the mats. Step back from the walls and stationary furniture by 5-10 cm.
4. Starting from the wall with the thermostat, lay out the heating mats with the cable down and the net up. The mesh can be cut to fit the room. It is impossible to violate the integrity of the cable and overlap the mats!
5. Insert a thermal sensor into the corrugation, put a plug on it and lay it into the prepared pipe at a distance of 50 cm from the wall.
6. Check the resistance of the cable and compare with the nameplate. Install the thermostat, connect the power supply and mat wires to it in accordance with the diagram attached to the device.
7. Make a test short-term start of the warm floor and check if the system heats up.
8. Draw the finished mats layout and sign all the elements. This is required for warranty and service purposes.
9. Lay the tiles. Apply the adhesive to the mat mesh with a notched trowel. A layer with a thickness of 8-10 mm must completely cover the surface without air pockets. Be careful not to damage the heating cable.
10. You can turn on the warm floor only after the glue has completely dried.

How to install a film underfloor heating

1. Think over the installation scheme and draw up a drawing, noting the location of furniture and large household appliances without legs. Provide 5-10 cm indents from the walls. The material does not fit into this space. Calculate the required amount of film and its power, depending on the resulting area.
2. Fix the back box under the thermostat and lead the power cable to it. Make a connection for the temperature sensor wire.
3. Prepare the base: level all the differences over 3 mm by 1 m, clean and prime the surface. Place a heat-reflective underlay with a laminated base over it and secure with double-sided tape. Do not use foil-clad materials!
4. Divide the heating foil into strips of the desired length, referring to the marked cutting lines. Space 5-10 cm away from walls and stationary furniture. Do not overlap the film! Place it end to end or leave between strips 1–2 cm, depending on the manufacturer's recommendations.
5. Mount the contacts: insert one end between the layers of film, and the other over the copper bus, squeeze them with pliers. Connect the wires to the terminals and crimp them carefully but securely. Connect all the pieces of film to each other according to the diagram in the instructions. Insulate the contacts and ends of the copper bus using the supplied bitumen tape.
6. Install the thermostat, connect the power cables and wires from the film. Tape the temperature sensor to the bottom of the thermal foil, to the heating strip. Route the wire from the sensor in a layer of heat-reflecting substrate and connect to the thermostat.
7. Run the system for 2-3 minutes and make sure that all areas of the film are warm.
8. Install the topcoat. It is necessary to lay polyethylene under the laminate. For linoleum or carpet, a protective layer of plywood or fiberboard must be placed on top of the film. During installation, be extremely careful not to damage the film with fasteners.