Hydronic underfloor heating spreads warmth through the floor at low temperature (30–35 °C). The result: a uniquely warm-underfoot comfort, no visible radiators, and a maximum heat pump efficiency (the lower the water, the higher the SCOP). In summer, it can even cool passively.
The figures that matter for quality underfloor heating, installed by our teams.
Water at 35 °C is enough to heat the entire surface. The lower the temperature, the higher the heat pump efficiency (SCOP).
Heat is spread across the entire floor surface: even distribution, no hot spots or cold zones.
No radiators, no visible convection. Walls are free for layout and decoration.
In summer, cool water circulates through the circuit: a 2–4 °C cooling effect, no compressor, virtually free (especially with geothermal).
The system’s thickness (insulation + pipes + screed) adds 8 to 10 cm of floor build-up. To plan for in renovations.
Underfloor heating has high inertia: it warms up and cools down slowly. Ideal for stable comfort, less suited to fast heating needs.
* Indicative values for a standard hot water system. Performance depends on the floor insulation and the floor covering.
Underfloor heating is the ideal emitter for a heat pump, but it has its constraints.
It comes into its own when you build or redo the floor. Three common cases:
The ideal moment: underfloor heating sits within the slab with no extra build-up. Paired with a heat pump, it’s the standard for new homes.
When the floor is redone from scratch (extension, full renovation), it’s the chance to fit underfloor heating with no extra demolition cost.
The underfloor heating + geothermal duo is the best performer: low-temperature water, record SCOP and passive geocooling in summer.
Low-temperature radiators are the alternative: they also work with a heat pump, without touching the floor. Paired with a high-temperature air-to-water heat pump, your existing radiators can also do the job.
A new 150 m² home with an air-to-water heat pump and underfloor heating across the whole surface. Water at 32 °C, a measured SCOP of 4.6, even warm-underfoot comfort. No visible radiators, walls entirely free.
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The emitter determines the heat pump’s efficiency and how comfortable it feels.
| Critère | Underfloor heatingVous êtes ici | LT radiatorsVoir la gamme → | Conventional radiatorsVoir la gamme → |
|---|---|---|---|
| Water temperature | 30–35 °C | 40–45 °C | 55–70 °C |
| Heat pump SCOP | The highest | Very good | Reduced |
| Comfort | Warm underfoot, even | Good | Convection |
| Visibility | Invisible | Wall radiators | Wall radiators |
| Installation | Floor to redo | Simple swap | Already in place |
| Cooling | Passive option | No | No |
| Ideal for | New build, major renovation | Renovation, replacement | Existing, hybrid |
Paired with underfloor heating, air-to-water delivers the best SCOP.
See air-to-water →The underfloor heating + geothermal duo = record efficiency + free geocooling.
Discover geothermal →Underfloor heating without floor insulation loses heat downwards. Insulate first.
See floor insulation →A hybrid also works with underfloor heating for optimal comfort.
See hybrid →Price ranges for installed underfloor heating and the related heat pump grants.
See prices →An overview of our heat pump solutions in Belgium.
Back to the heat pump guide →The price depends on the surface area, the type of insulation and the screed. Here are some benchmarks for an installed system.
See full heat pump prices & grants →* Indicative ranges for installed hydronic underfloor heating, excluding the heat pump. The heat pump is billed separately.
Tiles and stone are ideal (good thermal conductivity). Engineered parquet also works. Thick solid parquet and thick carpet slow heat transfer. We advise on the covering during the survey.
Yes, if the floor is being redone (stripping the existing one or an extension). The 8–10 cm build-up must be planned for: ceiling height, thresholds, steps. In new builds, the floor heating sits within the slab with no problem.
No, that’s its inertia: it takes several hours to reach temperature. But once warm, it delivers stable, continuous heat. It’s controlled by a room thermostat rather than in bursts.
Yes, by circulating cool water through the circuit (geocooling with a geothermal heat pump, or well water). The gain is 2 to 4 °C — gentle cooling, not air conditioning.
Absolutely. Without insulation, heat goes down into the subfloor instead of up. An insulation layer of 6 to 10 cm (PUR, XPS) under the pipes is essential.
Yes, significantly. The lower the water temperature, the more efficient the heat pump. With underfloor heating at 32 °C, the SCOP rises by 0.5 to 1 point compared with radiators at 55 °C.
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