Hydronic underfloor heating

How hydronic underfloor heating works

Plastic pipes (PEX or multi-layer) run over the system board, carrying water at temperatures typically between 30 and 40 °C. The screed above the pipes warms up and radiates heat into the room from the entire surface area. Each room has its own circuit, which starts and ends at the manifold. There, the circuits are hydraulically balanced and controlled according to thermostats.

The low water temperature is why underfloor heating works so well with a heat pump. The pump does not need to heat the water to 55 °C as required for radiators, and therefore consumes significantly less electricity. It also suits a condensing boiler, which operates at full condensation efficiency in low-temperature mode.

What is included in the supply

• Calculation of heat loss by room and design of pipe spacing (denser near windows and external walls).
• Thermal and impact sound insulation according to floor level, perimeter expansion tape, system board.
• Pipe laying, pressure test before concreting with protocol.
• Manifold with flow meters, optionally a mixing assembly and pump group.
• Coordination of screeding (anhydrite or cementitious), heating test and commissioning protocol for floor covering installers.
• Control: room thermostats, zone actuators, connection to heat source.

Anhydrite or concrete?

Anhydrite (poured) screed encases the pipes better, has higher conductivity and is poured quickly and evenly. Cement screed is more resistant to moisture, so we choose it for garages, utility rooms and anywhere where water exposure is a risk. For both types, the screed must cure and pass a heating test before laying the floor covering; otherwise, the floor may crack or the wood may warp.

Which floor coverings are suitable

Tile and stone conduct heat best; vinyl and poured floors work excellently. Wood and laminate are suitable if the manufacturer has approved them for underfloor heating and they have low thermal resistance. Thick carpets will essentially block the underfloor heating.

Spacing and circuits that make sense

The standard spacing is usually 10 to 20 cm, with denser laying near windows and external walls. We keep the length of each circuit such that the pump can push through it without issues and it can be balanced. Bathrooms get their own circuit because you want a different temperature there than in the bedroom. Combination with a heat pump or boiler: an overview of sources is available on our website. topeniachlazeni.cz.