Electric Underfloor Heating Questions

When operating on floor temperature, we recommend the floor temperature is set between 24 to 28 degrees Celsius.

You will first need to work out the total load of your heating mat. Each heating mat comes with a label attached on the power lead which will tell you the total power of the entire heating mat.
For example. If you have purchased a 200watt heating mat that is 10m2. The heating mat is 200watts per square metre, meaning the total power is 200 x 10 = 2000watts or 2kilowatt. Divide mains voltage into this and you end up with your Amps or current. 2000watts divided by 230volts = 8.69Amps.
Your electrician should use this information when working out what size supply to install for the heating mat. If in doubt contact our technical team for support.

Any kit size over 12m2 will typically be 2 separate heating mats as no manufacturers make singles mats larger than 12m2. So when purchasing a 20m2 heating kit you will receive 2 x 10m2 heating mats. Each heating mat comes with a 2metre power lead, these heating mats will need to be connected in parallel at the start near the thermostat. Both power leads should be installed and connected to the thermostat or a junction box before extending to the thermostat. You CANNOT join one mat onto the end of another mat as they are series resistive wires and they just won't heat up!

It depends on the size of the heating mat and the power per square metre. For example if you have a 200watt heating mat at 5m2 area. The total load is 5 x 200 = 1000watts which is divided by 230volts gives a total current of 4.34Amps.The system can be protected with a 5amp fuse in this instance.

No, you must control the underfloor heating using a thermostat that is hard wired via an isolation switch. The thermostat will prevent the heating wires from overheating and also reduce your running costs by maintaining the optimum temperature.

No. You will need one thermostat per room or per heating zone.

Yes, the heating mat is repairable, we recommend using the prowarm repair kit found on our site.

No, you cannot cut the heating wires or cables at all as they are series resistive wires. If you shorten one of the heating mats the remaining cable will be a lower resistance meaning you'll get more current through a smaller mat. It will run too hot and fail.

Each heating mat size that we supply if a different cable with its own unique resistance per linear metre, a shorter heating mat will have a higher resistance as it will not need as much current to produce the same output.

When calculating how much heating cable or mat you need, measure the room dimensions wall to wall, takeaway any fixed furniture from this area and deduct an additional 10%. You then round down to the nearest cable/heating mat size.

They are different manufacturers. There are no technical differences between Warmup and prowarm, the heating mats are constructed in the same way and are the same thickness.

With electric underfloor heating in small areas you can usually provide the supply via a fused spur as the load tends to be less than 13amps. When your room size starts to exceed 14m2 plus, you may need to calculate the load to determine whether you will need a dedicated power supply instead.

The 200W loose cable or heating mat is only recommended for use under tiles. This system can achieve fairly warm temperatures which can if not programmed correctly be detrimental to a floor finish that may be temperature sensitive such as carpet, vinyl, laminate or wood flooring.

You can, however we would strongly advise that an insulation board is installed first for a far greater efficiency. You also need to ensure that the subfloor is suitable to accept the floor finish. I.e. suitably reinforced ready for tiling.

We recommend that you use an electrician to install and connect the electric underfloor heating systems, along with a floor layer.

Heating mats

Heating mats are the same cable as the loose cable kits (2mm loose heating cable rated @10/12 watts/m) already spaced out for you and attached to a fully adhesive mesh backing. Heating mats are typically easier to install in larger areas, whereas loose cables are more suited for smaller or awkward shaped rooms (i.e. bathrooms) Our heating mats come in 3 wattages:
200 watts per square meterthis is the most powerful type of heating mat. It can be used beneath tiled or stone floors and is recommended for high heat loss areas such as conservatories. It should also be used where laying onto a concrete floor when not using insulation boards. The maximum area you can connect to 1 thermostat is 18m

150 watts per square meter

This is a mid-range powered mat, our most popular, which is suitable for most applications and can be used as a primary source of heating beneath most floor finishes. It should be noted that finishes such as Karndean or Amtico have a maximum of 150w per meter. The maximum area you can connect to 1 thermostat is 24m

100 watts per square meter

This is the lowest powered mat which is suitable for taking the chill off cold tiles – it is not suitable for a primary heating source. The maximum area you can connect to 1 thermostat is 36m2 Heating mats are for use on a finished subfloor such as concrete screed or plywood and we recommend they are encased in either a flexible tile adhesive (if laying tiles) or a flexible levelling compound if laying any other floor finish.

Underwood Foil heating mat

This underwood foil heating mat is designed for use underneath laminate or engineered wood floor finishes without the need for adhesive of levelling compound. It must be used in conjunction with Profoam or XP-Pro insulation boards, but once fitted the laminate or engineered wood can be installed directly on top! This system can also be used under carpet or vinyl BUT in this case it must also be used with Heat Pak Dual Overlay.

Heating Cables

The loose heating cable is rated at 10 watts per linear meter and is the same cable used in the heating mats. The cable comes on a drum and spacing must be manually measured (full instructions on how to do this are included in the kit).

In Screed Heating Cable

Must be encased in the finishing screed of the concrete floor (usually a minimum of 65mm as per Building regulations) with a minimum of 20mm of the screed above the cable. The same maximum outputs are recommended for the in-screed cable, that is, up to 200watts/sqm beneath tiles / stone and 160 watts/sqm beneath all other floor finishes.

The mats are 500mm wide and come in different lengths to suit the size of the room you require. For instance, if you require a 4m2 mat kit, it will come on a roll of 8m2 long by 500mm wide. This covers 4m2. You roll out the mat and cut it when you reach the end of the room then flip it over and come back the other way.

Our heating cables are 2mm thick, but you need to allow for your tile adhesive (5mm), your tile and any insulation board used.

Underwood - 140w per meter

Under Tiles / stone floors - up to 200w per meter

Under carpet or lino - maximum of 150w per meter

If you would like to heat a standard room which is well insulated 150 watts or greater is required. If you are heating a conservatory, which is considered high heat loss or a room with lots of fixed furniture such as a kitchen then we suggest 200w. 200w by nature heats up faster than the 150w so if you can use it then you may as well have the most powerful.

This depends on several factors. If you are covering 80% of the rooms total floor area and have a well-insulated room it can be used as a primary heat source. The heating system must be fitted with insulation boards such as Profoam, XP-Pro or Insulated tile backer boards depending on which system and floor finish you are installing. Tiles are the most efficient floor covering to install and you will achieve a much higher output and greater chance of heating your room with this type of flooring.

The system always works best if used with suitable insulation boards as this prevents the heat from going downwards and ensures it travels up. We understand that not everyone has the floor height to install a board so in this case you could use Fast heat thermal primer, which does not raise the height at all. (however this is not as effective as insulation boards)

Yes, our range of thermostats will switch up to 16amps so any combination of mats or cables can be connected as long as the total load does not exceed this. If you would like to switch a larger area with 1 stat then you can use a contactor to switch the load, please call for more info on this. When using more than two heating mat / cables to connect into 1 thermostat it may be a little tight to get all the cables into the thermostat terminals – in this case you can use a junction box to connect them which can be positioned on the wall behind a blanking plate or similar.

When installed correctly, typically underfloor heating systems can achieve between 24-27 degrees floor temperatures. The 200 watts heating mat under tiles can achieve a higher temperature however it is recommended to limit the floor temperature to 30degrees Celsius for comfort reasons.

You should aim to cover between 80-95% of the free floor space of the room. Covering less than 80 % of the floor area means you will end up with cold spots on your floor. We recommend that you measure the intended area to be heated, remove any fixed furniture and remove an extra 10% of your total measurement to ensure that you don't order too much heating cable or mat. The heating mats cannot be shortened, so its crucial you get the sizes correct, feel free to send a floor plan through to the sales team for their expert advice and sizing recommendations.

Most flooring manufacturers approve their products for use with underfloor heating systems, usually recommending that the maximum floor temperature does not exceed 27degrees Celsius, this is easy to setup on the thermostats sold with the kits. If in doubt we always recommend you check with your supplier that your wood or laminate floor is suitable to use with our underfloor heating systems

If you are using the underwood system as a primary heat source we always recommend using our Profoam insulation boards or the XP-Pro insulation boards. These boards come in different thicknesses and the thicker the insulation the better.

Yes - our system is suitable for wet areas and is fully 18th edition compliant, providing you follow the installation instructions. Our cables are all double insulated and have are fully protected with an earth screen or earth metallic covering. These systems must be electrically protected by a 30milliAmp RCD, if unsure speak to your electrician or our technical team.

Our mats are rated at 140w per m2.

The Heating mats are all 500mm wide and come in pre determined lengths from 1m2 to 12m2, eg: if you wanted to cover an area of 8m2 the mat would come 16 meters long by 0.5m wide, the mats can be cut and turned to suit any given floor space, this makes our system much more versatile than the old fashioned carbon film systems. (PLEASE NOTE DO NOT CUT THE CABLES).

The Underwood foil heating mats are rated at 140w per m2.

The Heating mats are all 500mm wide and come in pre-determined lengths from 1m2 to 12m2, eg: if you wanted to cover an area of 8m2 the mat would come 16 meters long by 0.5m wide, the mats can be cut and turned to suit any given floor space, this makes our system much more versatile than the old fashioned carbon film systems. (PLEASE NOTE DO NOT CUT THE CABLES).

Yes, most free-standing furniture is fine to use, we don't recommend installing it under any fixed appliances or fitted wardrobes etc, also thick rugs, dog beds etc can also cause localised heating issues.

When installing laminate or engineered wood on top of the Foil underwood heating mat we do not recommend using an underlay on top of the foil heating mat prior to laying the flooring. The insulation board underneath the foil heating mat (profoam or XP Pro insulation) will provide a cushion layer for the flooring as well as insulate against the cold subfloor.

Yes, you can wire 2 mats directly into the back of 1 thermostat. Providing you do not exceed the maximum load of 16amps.

The silver aluminium tape that comes with the kit needs to be placed across any mats that have been cut, this will ensure the mats earth continuity.

7mm to 18mm is the recommend range of thicknesses that we suggest. This ensures your system is working as effectively and efficiently as possible.

If you use our 6mm insulation boards the total thickness will be 8mm as the heating mat is only 2mm thick.

The foil heating mats can be cut and turned to suit any given floor space, this makes our system much more versatile than the old fashioned carbon film systems. (HOWEVER PLEASE NOTE DO NOT CUT THE CABLES).