There are two main types of electric underfloor heating systems, a mat system and a loose wire system.
The mat system consists of a heating cable which is already attached to a mesh which sticks to the substrate.
The loose wire consists of the heating cable on a coil which is run out across the floor and stuck down with fixing tape.
The advantage of the matting system is the speed and ease of install. With the cables already pre-spaced on the mesh all you need to do is run the mat out across the room. By cutting through the mesh, without cutting the cable, you can twist the mat to change direction allowing you to cover the entire floor.
A good quality Underfloor Heating mat will come with a self-adhesive mesh, which allows you to stick it directly to the substrate. It is always recommended to have the mesh above the cable as this prevents any cables from sticking up and potentially being damaged while tiling.
The loose wire systems are typically only used in an application where it is a smaller or irregular shaped room making it difficult to use a matting system. The loose wire system does provide greater flexibility for the manoeuvring of the cable however extra care needs to be taken to ensure an even cable spacing is maintained to avoid hot and cold patches.
The cable system is then stuck to the substrate using a fixing tape, generally a cloth weave tape. The Vario system offered by Thermogroup includes a fixing tape with pre-spaced markings helping you with getting the correct and even cable spacing.
The loose wire system has been around for longer than the matting system and as a result some installers are more confident and familiar with it than a matting system and prefer to work with what they know. It is always a good idea to check with your installer on the system they wish to work with.