Underfloor heating in the Costa Blanca

Why underfloor heating is taking over new builds

When you build or fully renovate, the heating-system decision impacts comfort for the next 30-40 years. A decade ago, the automatic answer was radiators with a boiler. Today, hydronic underfloor combined with aerothermal is the dominant install in modern new construction on the Costa Blanca, particularly in villas and large homes. Several reasons converge on comfort and efficiency.

Underfloor heats the entire floor surface to a gentle temperature (typically 26-29°C at the surface) instead of heating concentrated wall points with a radiator. The thermal sensation is very different: warm feet, evenly tempered ambient air, no convection currents stirring dust, no cold zones moving away from the radiator. Perceived ambient temperature with underfloor at 21°C feels equivalent to a room with radiators at 23°C, cutting energy consumption 8-12%.

Aesthetically and functionally, underfloor frees the walls completely. Without fixed radiators on the wall, furniture goes where you want, not where the heating system allows. The room looks cleaner and more usable. For modern homes with large glazed walls or minimalist decor, it’s the only option consistent with design.

Hydronic or electric

Hydronic underfloor is the complete system. Multi-layer cross-linked polyethylene tubing is laid in a serpentine pattern over each room’s surface, embedded in roughly 5 cm of self-levelling cement. Warm water (35-45°C) heated by the source (gas boiler, aerothermal or solar thermal) circulates through it. Each room has its own thermostat and a central manifold regulates individual flows. The most efficient option, the most used in new builds.

Electric underfloor uses an electric heating mat or cable embedded under the tile or floating floor. No boiler, no manifold, no piping. Install is simpler and faster (a day per typical room), so it’s often used in partial renovations where only a bathroom or kitchen is heated. Long-term electrical consumption is higher than hydronic, so for a whole home hydronic wins.

Renovations on existing properties

For a Costa Blanca home with existing underfloor that has started to fail (cold zone, leak, circulation noise), diagnosis requires specific tools. Thermal imaging to identify non-working circuits, electronic leak detector to locate loss points without breaking the floor, and manifold gauges to verify circuit pressures. In most cases we diagnose and repair without lifting the entire floor.

Most common repairs: replacing electrothermal manifold actuators that have failed and block a whole circuit, replacing the circulation pump when it no longer drives enough flow, balancing the circuit when there are thermal imbalances between zones, and full bleeding when there’s air in the system. Embedded tubing leaks are the most serious failure but also rare: quality multi-layer tubing has a guaranteed 50-year life.

Modern smart control

Underfloor pairs especially well with WiFi smart thermostats per room. The thermal inertia of the floor (slow to heat, slow to cool) makes fine hourly programming very efficient: start heating 1-2 hours before planned use, stop before leaving home, and the comfortable temperature holds through the planned period. For holiday homes, mobile remote control means the house is warm on arrival without having been kept warm during the whole absence.

We work with underfloor-specific control systems from Honeywell, Tado, Heatmiser and Uponor. Integration with Google Home and Alexa allows voice control for ad-hoc adjustments without opening the app.