Underfloor Heating is a proven technology which offers attractive benefits when integrated as part of a heating solution into residential or commercial buildings. By its nature it is a radiant heating system as opposed to convection based solutions such as radiators.

Radiant systems heat the people and objects in the room as opposed to the convective ‘top down’ stratified heat of radiators. The result is evenly distributed heat, resulting in lower operating costs and greater comfort.

In new build construction of residential units wet screed systems are the preferred method of installation on the ground floor. Upper floors can pose some design issues, namely structural requirements in timber frame construction or joisted upper floors require significant structural enhancement to allow a screed to be poured.

The potential alternative solutions to install underfloor heating in areas of light build construction are as follows:

                                      Screeded solution

As introduced above, the building structure is designed to facilitate the application and mass of screed, and in addition to an insulation layer either through the use of precast flooring, structural joists etc.

Modular composite wooden flooring boards

These systems are factory manufactured chipboard or ply panels with integrated under floor piping. The panels are typically placed on top of the joists in place of the floor boards, and typically laid in back to back arrays. Piping protrudes from one end of each flooring panel. The panels are piped in series within the floor joists with a main flow and return piping running along the end of the panel. The finished floor is laid on top of this product.

Piping and aluminium diffuser tray

In this configuration battens are applied a set distance below the top of the joist and plywood is used to form a carrier layer between the joists. Insulation is manually cut and inserted between the joists on the carrier plywood which fills the void almost to the top of the joist.

The insulation is routed continuously along the centre line. The aluminium diffusion tray is laid parallel to the joist span on top of the insulation. The routed channel is designed to accommodate the u-channel in the centre of the aluminium tray. This u-channel in the diffusion plate provides a recess to take the underfloor heating pipe. At both ends the joist is routed to form a notch to allow the pipe to turn 180 degrees.

EPS panels with aluminium diffusion layer

This solution is available in configurations as low as 13mm deep. The EPS panels contain a series of factory cut groves which run along the linear length of the panel to hold the pipe. The complete panel including the grove has a factory applied aluminium foil diffusion layer. The layer ensures an even distribution of heat and prevents heat deflection the zones below.

The floor joists are covered in plywood or a similar substrate and the EPS panels are bonded to the ply substrate layer. The pipe is then laid into the panel groves. Several manufacturer approved tile adhesives can be applied directly to the product and tiles can be applied directly on top. To facilitate the use of a soft floor finish eg carpet or cork a 6mm floating plywood floor can be laid on top of the EPS panels. Wooden floors can be laid directly onto the panels as a floating floor.

Contact us to find out which system is most suitable for your project. 

A common saying in Ireland is that, if you don’t like the weather all you have to do is wait five minutes for it to change.

Underfloor heating in Ireland needs to be designed with this maxim in mind. With such variable weather, your heating system needs to be able to respond quickly, supplying heat when needed, then turning off rapidly as the temperature increases. Greentherm underfloor heating systems are designed first and foremost to be controllable. A dedicated thermal store and a lightweight floor screed gives a fast response to changing conditions, ensuring optimal comfort and efficiency.

Some installers like to replace the dedicated thermal store with a thick slab of concrete or heavy screed, especially when combined with a heat pump system. They justify this as ‘thermal mass’ doing the same job as a thermal store, saving on the cost of a large cylinder.

The effect of ‘thermal mass’ is to make the effective control of the heating system almost impossible.

A system with too much thermal mass will respond far too sluggishly to changes in temperature or demands for heat. The underfloor heating systems will only begin to supply heat to the room one the floor slab surface has exceeded room temperature. In some cases, with heavy concrete floors, this can take hours.

Heat will continue to soak up through the slab long after the thermostatic valves have closed, pushing the room temperature beyond that set on the thermostat until the air temperature matches the slab. With so much heat stored in the slab, it will take hours for the room to cool back down again unless a window is opened.

The graph below illustrates the effect. The low thermal mass system in blue has already reached a comfortable temperature, before the high mass system in red begins to respond. The high mass system also overshoots the set ‘comfortable’ temperature, continuing to radiate heat even after it is no longer required.

Effect of ‘Thermal Mass’ on underfloor heating response time.

The effect is similar to trying to push a heavy train with no brakes. It takes a lot of effort to start it moving slowly. And once it is finally moving, it takes so much effort to pull it to a stop again that the train overshoots the point where it was supposed to stop and must be pulled back again. It responds slowly to temperature changes and takes a long time to settle down afterwards.

Compared to this, controlling a Greentherm underfloor heating system is like pushing a lightweight car. It takes little effort to get it moving, and once you stop pushing it, it stops all on its own. The thermal store acts as a heat ‘battery’, charging up and then releasing energy exactly when and where it is needed.

Your own comfort is at your fingertips.

Click here for more information on Greentherm Underfloor Heating.
Contact us to arrange a free, no-obligation consultation.