How Water Based UFH Works

Diagram of UFH System

The boiler feeds hot water to the manifold which distributes it to each room individualy based upon seperate thermostat settings.

In a water based UFH system, the boiler provides the hot water in a similar fashion to a standard radiator based system. It pipes the hot water straight to the manifold which is basically the distribution centre for the whole system. Every room to be heated is connected by a snaking loop of pipe to the manifold. As each room has a seperate connection to the manifold, it provides each of them with precise temperature control.

Controlled by a thermostat to a predetermined temperature, the manifold mixes the hot water from the boiler with the cooler water returning from the coils under the floor. As each room calls for heat, an actuator opens the pipe run to the room and delivers water to it at the correct temperature. When the room comes to temperature, the actuator then closes the valve until either the room cools or the room stat goes to a different setting and calls for more or less heat.

Normally, on the ground floor of a property, the coils of pipe are encased in concrete or screed, which in turn lies on a layer of very efficient insulation. When the system is operating, the coils heat the concrete in which they are encased and, with the reflective properties of the insulation, radiate the heat upwards.

On the first floor the pipes can still be encased in concrete, however they are usually installed into aluminium plates, which again radiate the heat upwards. The plates sit on top of the floor joists and then flooring is laid over the top.

The whole thing seems very complicated but in fact is a very simple solution and it is this simplicity that makes it a very efficient way to heat your home. One of the main benefits is that every room has its own digital, seven-day, programmable thermostat which provides total, flexible control by allowing each room to have its temperature set seperately. This allows you to have the bathroom several degrees warmer and maybe the bedrooms cooler for more comfort at night.