Advice for buying electric underfloor heating systems

What you will need for your underfloor heating installation.

Advice: all you need is the correct sized under floor heating system, a thermostat control and to make sure you have an R.C.D to cover the electrical supply.

Size matters –

It is essential to make sure that the correct sized heating system is ordered. Underfloor heating is only installed in areas that don’t have permanent furniture.

Always leave a 10 cm Border around the room when making your calculations.

The example room pictured below is 2.1m long by 3.2m wide, this equals 6.7m² of floor area. However after taking out the furniture the area for heating is only 2.9m2.

You always recommend a size smaller so if they want a mat they would order a 2.5 m2 (NOT A 3) or a 450 watt Warmtoes cable system.



Choose your system –

Loose Wire Underfloor Heating

Underfloor heating wire



Installing your Warmtoes loose cable or mat system is very straight forward. Please follow the detailed advice included with each kit.

  1.  Draw your area and make sure you have bought the right sized kit before you start installing.
  2.  Make sure the floor is clean and ready for the final floor finish. If the sub-floor is plywood you must prime the wood. Use a proper tilers primer and not a PVA.
  3.  Plan where the product will be installed and if it’s a loose cable system plan the spacing between the cables using the instruction manual.
  4.  Install the wire or the mat
  5.  We recommend you cover the heating with a flexible leveling compound before you tile.


For more advice installing HQ loose cable please click here.

For more advice installing our mat systems please click here.

More technical detail:

When installing either system it is very important to test the ohm’s and continuity at the start, middle and at the end of your installation. See how you test underfloor heating.

Now you can connect your thermostat. Always use a part P qualified electrician for any electrical work.

When the heating is installed the cold leads are fed into a junction box. It doesn’t matter where you fix these items, you may want to be hide in a cupboard. If you have a thermostat that reads air temperature this will need to be in the room. If you plan just to use the floor sensor (floor warming) then this isn’t necessary.

You must have a Residual current device (RCD)

All modern houses have an RCD. Rcd’s are designed to disconnect the circuit if there is any damage to the electricity circuit. RCD’s detect small leakage currents (typically 5–30 milliamperes) and disconnect the power quickly to prevent harm and maintain a safe enviroment.

Preparation for the electrics

You will have to chase the wall out and install a single deep (35mm) back box to house the thermostat with conduit (min 25mm). You will need to pull the sensor and the connection cables through this.


Our thermostats are 16 amp so you can install the following m2 of each type on each thermostat.

  1.  HQcable  = 3600 watts
  2.  Warmtouch 150 watt mat = 24m2
  3.  HQ 160 watt mat = 23m2
  4.  HQ 200 watt mat = 18m2

You can install larger areas using a relay/contactor – contact us for advice.


Click on the how to program an underfloor heating thermostat to see how easy a controller is to program.

Underfloor heating Hq’s electric underfloor heating kits are 100% efficient. The wire will last for the life time of your floor. This makes it not only an amazing value for money product, but also environmentally friendly. The mats are only 2mm thin. You will use far less leveling compound (saving you money) and add hardly any height to the depth of your floor. This product is far better than older, thicker wired systems.

When you know what to buy visit our shop.

Running costs Installing loose wire heating Installing mats