Underfloor heating is fast becoming a popular choice for heating a home. It only takes a few minutes to understand why this system is becoming ever more popular. So, what is underfloor heating and what are the benefits.

With an underfloor heating system your home is divided up into zones. Each zone is an area which is thermostatically controlled giving the occupant control over room temperature. Open plan areas such as a lounge/dining  area would also be considered as a single zone, again controlled by a single thermostat.  A zone should not be confused with a pipe circuit or loop as many larger zones or rooms may require several pipe circuits to effectively supply heat.

 
In simple terms hot water from a heat source such as a boiler is sent to a dedicated underfloor heating manifold. The manifold then blends the water down to a suitable ‘safe’ temperature distributing the hot water to each of the underfloor pipe circuits. Each circuit is controlled by a valve, the valve or valves if there are multiple circuits within a room are controlled by the thermostat. When the thermostat calls for heat the boiler is fired and the valve/s on the underfloor heating manifold are opened. The circulating pump activated thus allowing warm water to be pumped into the underfloor pipes.

The warm flow water circulates round the pipe loops transferring heat to the screed slab. The cooler returning  water  then 'topped up' warm water at the manifold and returned again around the slab.

Underfloor heating can be broken down in two way: by installation method or by heat source. By heat source I refer to the equipment supplying the hot water. Firstly I will talk about installation methods of which I see three different models:

• Screeded System – The screeded system is by far the most popular of all underfloor heating systems and is the simplest to install and the most cost effective solution. Already hugely popular on commercial installations this method is ideally suited to new build properties or extensions where a screeded floor is to be installed. Floor insulation such as celotex is installed into each room based upon current regulations. A foam strip is then placed around the perimeter of the room creating both an insulating barrier and a an expansion gap for the screed slab. Then, by means of a ‘system plate’ or ‘clip rail and pipe staples’ the pipe is fixed in place atop of the insulation. Screed of a type suited to the installation is then poured over the top creating the slab. It is this slab that will then become the surface heat emitter proving the heat to the room.

• Timber floor System – There are various products on the market for this type of system. One type is installed between the joists prior to the floor surface being laid, another type is installed from below after the floor surface is installed, and the last is installed as a false floor over the top of the installed floor surface. In each of these scenarios the final floor surface becomes the surface heat emitter. The engineering behind each of these systems follows the same logic which is to force as much of the heat from the pipes to go up through the floor. To prevent much of the heat being lost one option is  a standalone layer of insulation installed below the pipes, another is a layer of insulation that encapsulates the underside of the pipes, and another works by means of a reflective material that again sits below the pipes reflecting heat upward. On all counts the ideal scenario would see the pipes in direct contact with the floor surface.

• Over Top or Overlay System – Again there are various types of system to cater for this market which are born from two necessities. The first of these necessities is when a system is needed for retro fitting over the top of an existing floor where minimal impact to the overall floor height is critical. The second necessity factors in when more modern floor types such as TGI or POSI joists are at play. These floor types can quickly become overly complicated due to different joist centres and restrictions to installation requirements as well as being labour some and difficult to install. A thin panel laid atop the existing floor resolves these issues.