Underfloor heating is now one of the most popular ways to heat a home or apartment comfortably and energy‑efficiently. There are two main types: hydraulic (water‑based) systems and electric systems. Both have pros and cons, but today, hydraulic underfloor heating is almost always recommended.
Hydraulic underfloor heating
Hydraulic underfloor heating is the most widely used because it is comfortable, energy‑efficient and low‑maintenance. Thanks to its even heat distribution and low energy consumption, it fits perfectly with modern, sustainable heating solutions with minimal environmental impact.
How does it work?
Hydraulic underfloor heating produces heat through:
- a central heat source such as a boiler or heat pump,
- a network of pipes embedded in the floor (cast into the screed or placed on the concrete slab),
- hot water circulating continuously through the pipes in a closed circuit.
The floor heats up slowly but very evenly, ensuring a stable room temperature and a pleasantly warm feeling underfoot.
Who is it for?
Hydraulic underfloor heating is an excellent choice for new‑build homes, where sufficient floor height and insulation are available. In renovation projects, installation can be more challenging because you need an additional build‑up height of 10 to 15 cm. In that case — or in apartment buildings — floor‑grooving (infrezen) is a practical, space‑saving alternative.
Advantages
Hydraulic underfloor heating offers many benefits:
- Low energy consumption thanks to low water temperatures
- Perfect match with heat pumps and other modern heating systems
- Very even heat distribution for high and consistent comfort
- More environmentally friendly than electric underfloor heating and beneficial for your energy bill
- Suitable for large surfaces and entire homes, with strong long‑term performance
Electric underfloor heating
Electric underfloor heating may seem attractive due to its low purchase price and easy installation. However, in Belgium it is less suitable as a primary heating system. It is mainly useful in specific situations where space is limited or only small rooms need heating.
How does it work?
Electric underfloor heating works without a boiler or central heat source. The system consists of a grid of electric cables connected directly to the power supply. These cables are rolled out over the screed or concrete slab, just beneath the final floor finish, similar to a carpet.
When electricity flows through the cables, they act as a resistance, heating up and transferring warmth to the floor, which then gradually and evenly warms the room.
Advantages
- Simple and quick installation
- Lower purchase cost: €30 – €75/m²
- Often suitable for DIY installation, reducing labour costs
- Only 3–13 mm thick, ideal when build‑up height is limited
Disadvantages
- High energy consumption
- Higher energy costs due to electricity prices
- Less eco-friendly
- Not recommended as primary heating under Belgian regulations
For these reasons, electric underfloor heating is usually limited to small rooms (bathrooms), occasional heating or projects where no additional height is available.
Who is it for?
Electric underfloor heating consumes significantly more energy than hydraulic systems and is therefore less eco‑friendly and less economical in use. As a result, it is rarely recommended and increasingly discouraged by Belgian regulations.
Installation considerations
When installing underfloor heating, several technical and practical factors must be considered. In renovation projects, these elements can influence the choice of system.
Electric underfloor heating is not recommended. The following explanations therefore mainly concern hydraulic systems.
Build‑up height
Floor height is often the biggest challenge in renovations. Depending on the system, the required height varies:
- Traditional hydraulic systems require an additional 10 to 15 cm because the pipes are placed in or on a new floor layer.
- Grooved systems integrate the pipes into the existing floor, resulting in almost no height loss — ideal for apartments.
In urban areas such as Brussels, additional factors may apply:
- limited load‑bearing capacity of older floors,
- acoustic regulations requiring extra insulation layers,
- restrictions on modifying shared building elements, such as floor structure.
Suitable floor coverings
Not all floor types are compatible with underfloor heating. Choose a material that conducts heat efficiently. The Rd‑value (thermal resistance) is key: the lower the value, the less heat loss. For optimal performance, stay below 0.15 m²K/W.
Linoleum, PVC planks, stone and most wooden or parquet floors are suitable.
Practical tip: ask your flooring supplier for the Rd‑value to ensure compatibility with underfloor heating.
Can underfloor heating also be used for cooling?
Yes, hydraulic underfloor heating can, in certain cases, also provide floor cooling. Lightly chilled water circulates through the same pipes in the floor. This is only possible when the system is connected to a heat pump with a cooling function and the home is properly insulated.
Floor cooling lowers the indoor temperature gently and evenly, but it does not replace traditional air conditioning.
Electric underfloor heating is not suitable for cooling.
Is underfloor heating compatible with renewable energy?
Yes, absolutely. Hydraulic underfloor heating is perfectly compatible with renewable energy sources such as heat pumps and solar energy.
Because the system operates efficiently at low temperatures, it aligns seamlessly with sustainable heating solutions and supports the transition away from fossil fuels.
Does underfloor heating use more energy than radiators?
No. Quite the opposite: underfloor heating is usually more energy‑efficient than traditional radiators. The system operates at lower temperatures and heats evenly, meaning you need less energy to achieve the same level of comfort.
This benefit is especially noticeable when combined with a heat pump.