How to Lay Electric Underfloor Heating

electric heating system installer unrolling cables

Installation of an electric system should be fairly straightforward, though to ensure everything runs smoothly, it’s worth following a thorough procedure.

Consult a certified electrician when connecting the final mains connection, but this article can assist with installing an electric underfloor heating system by providing step-by-step instructions on preparing and laying insulation and mats, installing sensors as necessary and running cables.

Preparing the Floor

If you plan to install electric underfloor heating in a new build or renovation project, it’s vital that the floor be prepared correctly. Underfloor heating systems use thin heating wires that, when activated, radiate warmth across your floor surface and into the room—controlled by a thermostat to ensure optimal temperatures are reached—providing warming comfort across every inch of your room surface. Systems can either be installed as one whole system or as individual zones.

As soon as a room needs heating, its measurements must be taken and a sketch drawn showing where each mat and its power connections will go. This enables the ordering of enough heating mats without overlap and will prevent the necessity of cutting cables, which would void their warranties. They should then be laid out exactly in their correct places as indicated on their sketch and kept at least two inches from walls, cabinets, and fixtures for their safe installation.

Once the heating mats have been placed in place, they must be tested with a volt-ohm metre to make sure they’re operating effectively. Furthermore, it is a good idea to inspect the subfloor for signs of damp, grease, or oil that could interfere with the setting of the adhesive used to attach flooring, leading to issues in later years if left untreated.

Warmup Cement-Coated Insulation Boards should then be laid down, similar to how tiles would be applied, using flexible tile adhesive and then layering the insulation boards on top. This will prevent heat from escaping the floor, reduce energy use in heating the room and minimise seasonal cracking risks.

When using specialist floor coverings such as engineered wood, laminate, or vinyl tiles, a self-levelling compound may be applied over the top to seal and protect the heating wires beneath. It depends on the thickness and composition of your floor covering to determine whether this step is necessary.

Laying the insulation

Before undertaking the installation of an electric underfloor heating system on your own, it is a wise move to lay a small amount of insulation board or tiling backer board in the flooring area in which you are working; this will prevent heat from escaping down through the floor and allow your system to run more efficiently.

Once this has been installed, mats can be laid. Before beginning this task, it is a good idea to mark where cables will go in order to avoid wasting heat by placing mats in areas that won’t be utilised frequently and also ensure the cables don’t travel beneath fixtures like bathtubs and kitchen units.

Before and after installing cables, it is a wise practice to conduct tests using a volt-ohm metre in order to check that their resistance falls within acceptable parametres; this will ensure a fully functional UFH system.

Utilising the metre will also enable you to ensure cable runs do not overlap too closely and avoid crossing each other, which is crucial in protecting heating cables from becoming damaged. Furthermore, make sure the floor sensor and power supply cables are not placed too high and are at least 6 inches from any walls for optimal operation.

Once installed, make sure to keep heating mats at least 4 inches from cabinets or fixtures to help avoid damage to wires and the underfloor heating mat itself. After positioning cables, they should be tested again with a volt-ohm metre to make sure that they are in good condition before proceeding with installation.

Electric underfloor heating installation can be completed as a do-it-yourself project; however for best results, it is advisable to hire professional installers. They have all of the tools necessary for expeditious completion as well as knowledge of any electrical regulations that must be observed.

Laying the mat

Once the insulation and floor surface are in place, it’s time to lay the mat. This may be a relatively straightforward task depending on what kind of system is in place, whether as part of a new build or a retrofit to an existing room. If in doubt, seek professional assistance; they will have all of the right tools at their disposal and understand electrical regulations, so any work conducted adheres to them fully.

Heating mats should be laid in a pattern that complements both the room and any fixed fixtures within it, with insulation underneath to avoid heat loss through downward flow and edge insulation added around edges to stop any heat escaping into walls. Before sticking down your heating mat, it’s advisable to draw out how your cable runs will fit within this floor space, detailing where they begin and end so as to ensure they don’t become cut or crossed by other wiring, which could cause them to overheat and cause an accident.

Once the mat is in place, it is wise to conduct a multi-metre test in order to confirm continuity of power and that its reading falls within acceptable parametres as detailed in your installation instructions. Any exposed wire should be protected using foil tape, while cable runs should not exceed 50mm apart or they could overheat and become dangerously hot.

After positioning the sensor in the room (see this guide for more details), connect it to the thermostat and let it know when the desired temperature has been met; the system can then shut off automatically.

Before beginning to lay the floor covering, it’s wise to spend some time considering where the cable connections will be placed; this should be relatively straightforward, provided there are no obstructions in their way. Once complete, it’s simply a case of connecting the thermostat, controller, sensor, and any other connected points via electrical cable.

Connecting the wires

Once your layout is finalised, the next step in connecting the wires should be connecting them together. Care should be taken when connecting these wires, as following the manufacturer’s instructions is key. Using a multimeter to check power continuity and resistance within allowable limits is essential to ensuring optimal functioning. It is also vital not to cut or otherwise damage mat cables since this would compromise their ability to function correctly in the future.

Wires can either be adhered to a mat or laid loose; when doing the latter, you must first have planned out where you want your thermostat and sensor to reside. When positioning mat cables under floor level, they should come to an end where they connect to the controller and thermostat; additionally, ensure any sensor cable ends fit within this zone as well.

As much as possible, it is preferable to avoid routing the heating cable along the same path as plumbing pipework in order to reduce downward heat loss and potential seasonal cracking issues. Doing this also helps save on energy usage since only when necessary will the cable turn on and use energy.

Depending on the type of underfloor heating (UFH) system you choose, cables may either be attached directly to a mat or laid loosely around the room. Electric UFH systems tend to stick the cables directly onto their mat, while loose cable installation uses short strips of tape as anchor points so as not to get dislodged while installing tiles. To keep things secure when installing this type of cable UFH system, it is advisable to use short strips of tape around its perimeter to hold it in place and ensure it won’t become dislodged during tile laying processes; otherwise, you risk dislodging when laying your tiles!

Installing underfloor heating requires many steps and professional assistance is vital if it is to go smoothly. If you do not feel confident enough in yourself to complete this work yourself, seek a quote from an electrical specialist; that way, you will know it’s being completed to the highest standards.