Underfloor Heating vs. Radiators - Summary
The choice between underfloor heating and radiators is one of the most important decisions for new construction or renovation. Both systems have their merits – but which is optimal for your situation?
Technical Basics
Underfloor heating is a surface heating system where heating pipes are laid in the screed. Heat transfer occurs primarily through radiation (~60%) and convection (~40%).
| Parameter | Value per DIN EN 1264 |
|---|---|
| Standard flow temperature | 35°C |
| Max. surface temperature (living area) | 29°C |
| Max. output living area | ~100 W/m² |
| Typical standard output | 75 W/m² (wet system) |
Conventional radiators transfer heat through convection (70-80%) and radiation (20-30%).
| Parameter | Value per DIN EN 442 |
|---|---|
| Standard flow temperature | 75°C |
| Standard return temperature | 65°C |
| Typical standard output | 2,650 W/m² (Type 22) |
Suitability for Heat Pumps
| System | Flow Temperature | COP | Annual Electricity Costs* |
|---|---|---|---|
| Underfloor heating | 35°C | 4.5 | ~€900 |
| Underfloor heating | 40°C | 4.0 | ~€1,000 |
| Radiators (optimized) | 45°C | 3.7 | ~€1,080 |
| Radiators (standard) | 55°C | 3.0 | ~€1,330 |
*Assumption: 12,000 kWh heating demand, €0.30/kWh electricity price
Key Takeaway
Underfloor heating is technically the ideal heat transfer system for heat pumps – it enables low flow temperatures and thus maximum efficiency. Its physical output limit of about 100 W/m² is sufficient for well-insulated new buildings and energy-renovated old buildings.