How to Choose Electric Underfloor Heating: Cable, Mat, or Film?

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How to choose electric floor heating: cable, mat or film?

Electric floor heating is currently available in three basic forms – heating cable, heating mat and heating film. At first glance, it might seem like three variants of the same thing, but in practice there is a fundamental difference between them: different construction, different conditions of use, different installation height, different installation method, and different costs. Choosing the right solution has a direct impact on whether the heating will work reliably for decades, or end up requiring a floor repair after two years.

This article will explain exactly what each type is, how they differ, in what situations each of them makes sense, and what to watch out for when choosing. We won't beat around the bush – let's get straight to the point, with concrete values and examples from real projects.

Three basic types of electric floor heating

Before we start comparing, it's good to know what we're actually talking about. Each type has its own physical nature, from which all its properties – both positive and limiting – stem.

Heating cable

A heating cable is a simple resistance conductor (or two conductors in one sheath) that generates heat when electric current passes through it. It is usually supplied in two variants: single-core and twin-core. A single-core cable must have both ends led to one electrical box – this is its main disadvantage, as it can be complicated to physically manage this on small areas. A twin-core cable has both ends in one place, making installation much more convenient.

The cable is laid by hand in loops (serpentine pattern) with a set spacing between individual lines. This spacing determines the resulting specific power – the smaller the spacing, the higher the power per square meter. The heating cable is typically covered with a layer of self-leveling compound or anhydrite screed mixture, or laid directly into a sand-cement screed. The resulting thickness depends on the cable diameter and the thickness of the covering – it usually ranges between 30 and 50 mm, including the final surface layer.

An example is the HAKL TCX 10/1230W heating cable, which is a twin-core heating cable with a total power output of 1,230 W, designed for areas typically ranging from 8 to 14 m². This particular type has a specific power of 10 W/m, which is a standard value for comfort heating under tiles.

Heating mat

A heating mat is basically a heating cable glued onto a fiberglass mesh in evenly spaced loops. It is a prefabricated product with a fixed spacing, which means the specific power is fixed by the manufacturer – most often 100 or 150 W/m². The mat is laid without the need to manually measure distances between loops, which significantly simplifies installation.

Mats are available in various widths (typically 0.5 m or 1 m) and lengths. The mesh can be cut along its length – but never the cable itself – allowing the mat to be adapted to irregular floor plans. The mat is typically laid in adhesive directly under tiles, meaning a minimal increase in floor height – usually 8 to 12 mm including the adhesive and tiles.

Heating film

A heating film is a thin (0.3–0.5 mm) graphene or carbon heating layer laminated between plastic films with resistance strips instead of a cable. Heating here is planar – the entire film surface heats up evenly. Films are not covered with adhesive or embedded in screed – they are laid loose or fixed and covered with a floating floor (laminate, vinyl flooring, carpet). They must not be used under tiles glued with adhesive – the adhesive would mechanically damage the film, and moisture would compromise the electrical insulation.

Films have the lowest heat accumulation of all three types, respond quickly to the thermostat, but are suitable only as supplementary (comfort) heating – they do not reach the power required for primary room heating.

When to choose a heating cable

A heating cable is the most flexible solution in terms of power and area. Because you choose the spacing between loops yourself, you can precisely set the required specific power. This is a key advantage, for example, in situations where you need higher power for primary heating (150–200 W/m²), or conversely lower power for comfort supplementary heating (80–100 W/m²). A mat with fixed spacing does not give you this freedom.

From practice: a customer with a new family house with tiled flooring in a large living room (40 m²) needed primary heating where the exterior wall lacked sufficient insulation. A mat with a standard power of 150 W/m² wasn't enough – we needed a cable with an 8 cm spacing, giving a power of ~175 W/m². This wouldn't have been possible without a cable.

Another typical use case for cable is irregular floor plans with numerous alcoves, columns or other obstacles, where a mat would be needlessly wasted through cutting. The cable can simply be routed along the outline of the obstacle without material loss.

Disadvantages of cable: it requires screeding, which will increase your floor height by at least 40–60 mm in total. This can be a problem in renovations where you have fixed door heights and existing screeds. Installation also takes longer and requires greater precision – you must maintain even spacing and properly fix the cable with mounting tape before covering it.

We cover heating cable installation in more detail in the article Installing a heating cable: spacing, covering and connection, where you will find the exact procedure for calculating spacing and recommended screed mixture thicknesses.

When to choose a heating mat

The heating mat is the most popular type of electric floor heating, and for good reason. It combines sufficient power for comfort (and in some cases even primary) heating with ease of installation, which even a skilled DIY enthusiast can handle. A power of 150 W/m² is fully sufficient for primary heating in most common well-insulated rooms, while 100 W/m² is enough as a comfort supplementary layer under tiles in bathrooms or hallways.

The mat is the ideal choice in these situations:

Bathroom: Regular floor plan, tiles, low installation height – the mat is almost always the first choice here. A typical bathroom of 5–8 m² with a 150 W/m² mat provides comfort even in winter with primary heating.
Kitchen: Under tiles near a countertop or kitchen unit, where you want a warm floor without added screed height.
Hallway: Fast and clean solution, minimal floor height increase, simple installation.
Renovation without demolishing screed: The mat goes directly into adhesive on top of the existing floor, no need to demolish the existing screed. You save both time and cost.
Toilet, utility room: Small area, low cost, quick installation.

Practical example: a customer was doing a complete renovation of a bathroom and hallway in an apartment block. The existing screed was fine, she just wanted new wall and floor tiles with floor heating. We laid the mat directly onto the old leveled screed, covered it with adhesive, and glued on new tiles. Total floor height increase: 20 mm. We only had to shave 18 mm off the bottom of the doors – no demolition, no screeding, done in one day of professional work.

Limitation of the mat: because it has a fixed spacing, you cannot set the power yourself. If you need power higher than 150–160 W/m² (which is rare in standard insulated new builds, but real in older houses with thin walls), the mat won't work and you'll need a cable. Also, on irregular areas with columns, corners and alcoves, relatively significant waste occurs when cutting.

You can find a detailed installation procedure in the article Installing a heating mat under tiles: step-by-step procedure.

When to choose heating film

Film has the most specific conditions of use of all three types and is most often chosen incorrectly. Let's state this clearly:

Film is intended exclusively for use under floating floors – laminate, vinyl planks (LVT/SPC), sorted carpet. You must not glue it into adhesive, cover it with screed, or fix it with glue. The film is simply rolled out onto thermal insulation with a reflective foil, the individual strips are connected according to the instructions, and the whole thing is covered with a floating floor.

Advantages of film:

Minimal floor height increase – film + underlay + laminate = 8–15 mm total.
Fast installation without wet processes – the surface layer can be laid on the same day.
Fast response to temperature change (low heat accumulation).
Possibility of removal and reuse when replacing the floor.

However, the limitations of film are significant:

The power of films is typically 60–80 W/m², which is too little for primary heating – film is exclusively a comfort supplementary solution.
It must not be used under tiles or other glued surfaces.
It must not be covered by furniture without legs (sofa, cabinet) – there is a risk of overheating and damage.
Floating floors must have a thermal resistance of the surface layer of max. 0.15 m²K/W – most thick laminates exceed this limit. Always check the floor manufacturer's specifications.
Wet areas (bathroom, kitchen) are unsuitable for film – laminate + moisture = a problem, even without the film.

From practice: a customer bought film for a bathroom because "it's thin and won't raise the floor." That's true, but film cannot go under tiles set in adhesive, and laminate doesn't belong in a bathroom either. We ended up with a 150 W/m² mat under ceramic tiles – which was the correct choice from the start.

Power: how many watts per square meter do you really need

This is a question many people ask only after choosing a system – and that is a mistake. The required power directly affects which system you can even use.

The following basic guideline values apply:

Comfort (supplementary) heating: 80–100 W/m² – bathroom, hallway, kitchen with another primary heat source.
Primary heating of a well-insulated new build: 120–150 W/m² – a 150 W/m² mat is sufficient.
Primary heating of an older building with poorer insulation: 160–200 W/m² – cable with adjustable spacing is required.
Bathroom with an exterior wall or above an unheated space: at least 150 W/m², preferably 160–180 W/m².

Power calculation depends on the room's heat loss, which is influenced by insulation, north/south orientation, air exchange, and window type. In the article What power of electric floor heating do I need for my space? you will find a detailed calculation procedure as well as practical tables for various types of spaces.

Remember: the effective heating area is not the same as the total room area. Neither cable nor mat is laid under fixed furniture (cabinet, bed without legs), under built-in units, or under the toilet bowl. In practice, the effective area of an 8 m² bathroom may be only 4.5–5.5 m², which significantly changes the total required power. Keep this in mind when calculating as well.

Thermostats: an essential part of every electric floor heating system

Every type of electric floor heating – cable, mat, and film – must be controlled by a thermostat. Without a thermostat, the heating would run continuously, which is energy-inefficient and also dangerous – there is a risk of overheating the floor and damaging the surface layer.

Thermostats fall into three main categories:

Manual mechanical thermostat – the simplest, without a display, a rotary dial. No time programming, but reliable and cheap. Suitable where you don't need automation.
Digital programmable thermostat – display, temperature setting in °C, weekly program, floor and air temperature sensor. For example, the HAKL TH 900 digital thermostat falls into this category – it offers clear control, dual-sensor measurement (floor + air), and full weekly programming. It's a practical choice for most standard installations.
WiFi thermostat – control via smartphone even remotely, integration with Google Home / Amazon Alexa, remote consumption monitoring. For example, HAKL TH 951wifi or HAKL TH 952wifi – both allow full control via the app, with the TH 952wifi additionally featuring a color display and more advanced settings. Suitable for smart homes or people with irregular schedules who want to keep control over heating even while on the go.

Important technical parameters to consider when choosing a thermostat: maximum load in amperes (typically 16 A = 3,600 W, a contactor may be required for larger areas) and type of temperature sensor (NTC 10k is the most common standard, but check compatibility with your cable or mat). Thermostat selection is covered in more detail in the article How to choose a thermostat for electric floor heating: manual, digital or wifi?

Comparison overview: cable, mat, film

Property	Heating cable	Heating mat	Heating film
Typical power (W/m²)	adjustable 80–200	fixed 100 or 150	60–80
Floor height increase	40–70 mm	20–30 mm	8–15 mm
Suitable surface layers	tiles, stone, terrazzo	tiles, stone, wall tiles	laminate, vinyl, carpet
Primary heating	✓ yes	✓ yes (150 W/m²)	✗ no
Wet processes (screed/adhesive)	required	adhesive only	none
Installation difficulty	medium to high	low to medium	low
Suitable for bathrooms	✓ yes	✓ yes	✗ no
Power flexibility	high	limited	low
Relative installation cost	higher	medium	low

Electric floor heating as a primary heat source – what to watch out for

Electric floor heating is increasingly being used as a primary heat source, and not just in smaller rooms. In well-insulated new builds with low specific heat demand (energy class A0/A1), it is a fully viable solution. However, there are several facts you should know in advance:

The operating cost of electricity is higher than with a heat pump or gas. That's a fact. With good insulation and smart control via a thermostat with a night zone (lower temperature at night), you can significantly reduce operating consumption – but electricity will still be more expensive than gas or wood. If you're considering primary electric floor heating, ideally combine it with photovoltaics and storage.

The floor must have sufficient thermal capacity. Tiles and stone are ideal – they accumulate heat and release it steadily even after the heating is switched off. Laminate or vinyl accumulate minimal heat and cool down quickly when switched off. This is acceptable for comfort supplementary heating, but disadvantageous for primary heating.

Thermal insulation beneath the system is essential. If you don't have sufficient insulation downward (into an unheated attic, garage, or ground), heat escapes downward instead of warming the room. The minimum recommended thermal insulation value beneath the heating system is 0.04 W/mK at a thickness of at least 30–50 mm above ground (extruded polystyrene EPS or XPS). Without it, you could have a system running continuously while the room remains unheated.

The question of primary versus supplementary heating is covered in more detail in the article Electric floor heating as a primary vs. supplementary heat source.

Electric floor heating under various types of flooring

The choice of heating system must always be based on the type of surface layer you will have. At the same time, the surface layer itself must be compatible with floor heating – not all flooring is suitable for this.

Ceramic tiles and stone: An ideal combination. High thermal conductivity, trouble-free covering of the mat with adhesive, long service life. Use a mat or cable.

Vinyl (LVT/SPC): Modern vinyl flooring is increasingly thermally conductive, and most manufacturers certify it for floor heating up to a maximum surface temperature of 27–28 °C. Always check the specific product. You can use film (floating installation) under vinyl, or in some cases a special thinner-profile mat for glued installation.

Laminate: A thermal resistance of laminate R ≤ 0.10 m²K/W is a condition for most systems. Thick laminate boards (12–14 mm) may exceed this limit. Laminate + film = floating installation. The surface temperature must not exceed 27 °C – otherwise deformation and joint separation occur. Front heating under laminate with film is comfortable; primary heating is problematic.

Wood flooring (solid, multi-layer): Wood and floor heating are compatible, but require special conditions – maximum surface temperature of 27 °C, wood moisture content of 6–9%, and the system must have a slow temperature ramp-up on first start-up. Neither mats nor cables are glued under wood – wood is laid floating or glued directly onto a screed with a cable.

You can find more about floor compatibility in the article Electric floor heating under various types of flooring: tiles, vinyl, laminate.

Practical decision-making process: how to choose correctly

Finally, let's summarize it into a simple decision tree that covers 90% of real-life situations:

1. What will the surface layer be?
→ Ceramic tiles / stone → continue to step 2
→ Laminate / vinyl / carpet → consider film (comfort) or mat for glued installation
→ Wood (solid) → special conditions, consultation required

2. How much room do you have to increase floor height?
→ Less than 30 mm total → mat
→ More than 40 mm total → cable or mat
→ Renovation without demolition → mat

3. Primary or supplementary heating?
→ Supplementary comfort (bathroom, hallway) → 100–150 W/m² mat is enough
→ Primary, well insulated → 150 W/m² mat or cable
→ Primary, older building → cable with adjustable power above 150 W/m²

4. What is the area and its shape?
→ Regular shape, up to 15 m² → mat
→ Irregular floor plan, columns, alcoves → cable
→ Over 20 m², low spacing needed → cable

Frequently Asked Questions (FAQ)

Can I use heating film in a bathroom?

No. Heating film is not intended for damp areas, and it is compatible exclusively with floating floors (laminate, vinyl). A bathroom with ceramic tiles requires a mat or heating cable – both are intended for wet areas, have the appropriate IP protection, and are safely embedded in adhesive or screed.

Do I always need a professional electrician for the connection?

Yes. Electric floor heating must be connected by a certified electrician who issues an inspection report. Without an inspection, you have no valid insurance in case of damage caused by the electrical equipment. Laying the mat or cable on the floor itself (without electrical connection) can be done by a DIY enthusiast, but connecting to the mains installation belongs to an electrician.

What is the service life of electric floor heating?

Quality heating cables and mats from proven manufacturers have a guaranteed service life of 25–50 years when properly installed and operated with a thermostat (without overheating). Films generally have a shorter service life – around 15–25 years, depending on quality and operating conditions. The key condition for a long service life is always a thermostat with a floor temperature sensor – without it, there is a risk of overheating and accelerated degradation of the cable insulation.

Can I lay a mat or cable myself, without a professional installer?

A handy DIY enthusiast can manage the physical laying of a mat or cable if they carefully follow the installation instructions, maintain minimum distances from walls (min. 5 cm) and from other heat sources (min. 20 cm), and don't cross cable loops. Before covering and before laying tiles, it is mandatory to measure the cable resistance with a multimeter and record it in the warranty certificate. The electrical connection must be done by an electrician. You can find a detailed procedure in the articles Installing a heating mat under tiles: step-by-step procedure and Installing a heating cable: spacing, covering and connection.

What happens if I damage the cable while laying tiles?

This is the most common cause of faults, which you can read about in the article Common electric floor heating faults and how to fix them. If the cable is damaged during tile laying (for example, by a chisel), a repair using a special connector (a crimped cable connector designed for the specific cable type) is necessary before covering. After covering, locating and repairing the fault is much more expensive and usually requires milling out the tile at the fault location. Therefore, measure the cable resistance not only before covering but also after laying every 10 m² of tiles – if the value changes, the fault is fresh and easier to locate.

Is electric floor heating expensive to run?

It depends on several factors: house insulation, climate zone, set temperature, length of the heating season, and electricity price. For reference: a 6 m² bathroom with a 150 W/m² mat (total power 900 W, effective area ~5 m²) with a thermostat and an average operating time of 4–6 hours per day costs about €20–30 per month in winter at an electricity price of €0.20/kWh. Supplementary heating in a hallway is significantly cheaper. For primary heating of an entire house, costs are naturally higher and the calculation must be individual. You can achieve savings with a smart thermostat with a weekly program – for example, the WiFi thermostat HAKL TH 952wifi, which allows you to schedule a temperature reduction at night or during vacations, even remotely via the app.

Conclusion

The choice between cable, mat and film is not a matter of taste or price – it is primarily a technical decision that must be based on specific conditions: type of surface layer, installation height, required power, character of heating (supplementary or primary), and the shape of the area. For most common bathroom and hallway renovations, a mat under ceramic tiles is almost always the optimal choice. Cable makes sense for larger areas, when higher power is needed, and for irregular floor plans. Film is ideal where you want a minimal floor height increase under a floating floor and where comfort supplementary heating is sufficient.

Let yourself be guided by the actual parameters of your situation, not by marketing claims. And if you're not sure, it's better to consult an expert before installation – fixing mistakes in the floor is much more expensive than a consultation at the start.

Do you have a question about this topic?

Can't decide or dealing with a specific situation in your household? Write to us - we'll be happy to advise.