The heating element is the most important part of the electric underfloor heating system. It is constructed of a metal that has a resistance so that whenever the system is turned on and current is flowing through it it produces heat. All metals, apart from superconductors, produce heat when electricity flows through them, however the amount produced and their efficiency varies.
Heating elements can be produced in many different ways. The most common heating elements are made of one thick copper wire surrounded by an outer insulation. A more technologically advanced form of these wires, suitable for higher output systems, uses a spun wire of between three and 9 strands to create a stronger and more stable heating element. Finally, an alternative method of construction uses a very thin heating element spun around a central core to produce a heating wire with increased flexibility.
Heating elements are usually insulated with Fluoropolymer as this material has a very high melting point which makes it particularly suitable for use in undertile heating cables. Fluoropolymer is, however, less suitable for use in systems laid directly beneath wooden, laminate or carpeted floors as the heating system can reach dangerously high temperatures without the insulation failing. Heat Mat’s underlaminate system uses a PVC based inner insulation that is calibrated to fail in such a way that if there was a dangerous build up of heat beneath a laminate or wooden floor it would automatically melt ensuring the RCD would then switch the system off.
Most underfloor heating wires use a copper based metal to produce the required heat as it is a cost effective and widely available material for manufacturing, however a number of different alloys are used depending on the systems individual requirements.