What you will need for your underfloor heating installation

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

Installing the underfloor heating mats or wire

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

For more advice installing HQ loose cable please click here.

For more advice installing our mat systems please click here.

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. You can install more than one mat or wire on a thermostat but it can’t exceed 16 amps.You can install larger areas using a relay/contactor – contact us for advice

Warmtoes cable  = 3600 watts

Warmtoes 160 watt mat = 23m²

Warmtoes 200 watt mat = 18m²

Calculating Amps –  m² x total watts for the area, divided by volts (240) = Amps

Example – 5m² 200 watt mat = 5 x 200 = 1000 watts total.  Then divide by 240 to get amps, in this case, 4.2 Amps.

Running costs = approximately 2p per m² at 160 watts and 2.5p per hour for 200 watt

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

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.

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.