How Does Underfloor Heating Work?

How Underfloor Heating Works: A Guide for UK Tradespeople

Understanding how underfloor heating works is essential for any UK tradesperson aiming to deliver professional advice and expert installations. Unlike traditional radiators that rely on convection, underfloor heating (UFH) provides warmth through radiant heat. This method transforms the entire floor into a low-temperature emitter, evenly distributing heat throughout the space and creating consistent comfort from wall to wall.

The Mechanism of Radiant Heat

Radiant heating involves the direct transfer of heat from a warm surface to surrounding objects and people. In a UFH system, the floor becomes that warm surface, radiating heat gently upwards. This avoids the common issues found with radiators, such as hot and cold spots or draughts. Because the system heats such a large surface area, it requires significantly lower flow temperatures — typically 35–65°C for wet systems — compared to traditional radiator systems that may exceed 70°C. As a result, energy efficiency improves, particularly when UFH is paired with low-temperature heat sources.

Wet Underfloor Heating Systems (Hydronic)

Wet UFH systems are commonly used in new builds and large-scale renovations. Here’s how they function:

  • Heat Source: A gas or oil boiler, biomass unit, or renewable heat pump provides heated water.
  • Manifold: Water flows to a central manifold that distributes it through multiple pipe circuits. Each circuit serves a heating zone, and integrated flow meters help balance the system accurately.
  • Piping: Installers lay flexible PEX or Pert pipe in loops, either embedded in screed, clipped over insulation, or routed through preformed panels.
  • Heat Transfer: As warm water circulates, it releases heat to the floor structure, which then radiates warmth into the room.
  • Controls: Each zone is regulated by a thermostat that monitors temperature and adjusts pump activity accordingly.

Electric Underfloor Heating Systems

Electric UFH offers a convenient, dry-fit option for retrofits and small spaces. It works as follows:

  • Heating Mats or Cables: Resistance wires are either embedded in mats for easy rollout or laid individually onto insulation boards.
  • Installation: The mats or cables sit just beneath the final floor covering, providing rapid heat-up times.
  • Power Connection: The system connects directly to the mains via a fused spur, with no need for plumbing.
  • Thermostat Control: A floor sensor and thermostat work together to maintain safe and efficient temperatures.

Whether you’re installing wet or electric UFH, both systems offer reliable, energy-efficient heat and improved comfort. By fully understanding how underfloor heating works, you’ll be better equipped to specify systems, reassure clients, and install with confidence. Discover our full range of underfloor heating kits or explore components tailored to wet and electric systems.