There are some generic rules to follow when measuring up for underfloor heating and there are also specific rules that only apply to a certain room type. In general, if you cannot walk over it then do not heat beneath it. This applies to kitchen units, islands, fixed flat bottomed furniture and bathroom furniture that is fixed to the floor rather than wall hung. There are some circumstances when you may wish to heat beneath furniture, for example a kitchen island overhang, but as a rule if when measuring up you keep to the main area of the floor on which you can walk then you will not go far wrong.
Please read our guide below and if you have any questions then please call our award-winning technical support team on 01444 247020.


When measuring up for a bedroom, typically the wardrobes and any fixed flat bottomed furniture is deducted from the total floor area. Some choose not to heat beneath the bed if it is intended to be used for storage space. Once the free floor area is worked out we then deduct around 10% to work out the mat size required - this fitting space brings the mats in from the skirting and the edges of the furniture. As bedrooms are often kept at a lower temperature than other rooms in the house our 160W heating mats or our 150W Combymat system should be suitable.
Bedroom Electric Underfloor Heating


For kitchens, only heat the main area, so avoid the units, and if there is an island then measure around it. If the kitchen has a breakfast bar you may wish to heat beneath it in the footwell. If the kitchen is tiled and the units take up a large proportion of the floor, 25% or more, then using our 200W heating mats or 240W heating mats are the best choice for primary heating. If the kitchen is an irregular shape then to make the installation easier we would recommend using our  3mm heating cable.
Kitchen Open Plan Electric Underfloor Heating


Bathrooms follow the same rules as with other rooms, measure around floor mounted fixtures and unless the bath is free-standing and has an air gap beneath it, measure around it. Similarly with boxing-in of pipework, deduct this area from the total. Unless the heating is being used only to take the chill from the floor we recommend with tiles using our higher output 200W or 240W heating mats. Up to 200W/sqm can be achieved with 3mm Cable if the room is irregularly shaped and a heating mat would be difficult to fit.
Bathroom Electric Underfloor Heating

In no circumstances do we recommend using a percentage to calculate the deduction required for kitchen units or fixed furniture.  With underfloor heating, the fitting space percentage deduction is only made after the deduction of units or fixed furniture. 


If you have any questions please call our technical department to discuss options on 01444 247020 or contact us here.