What does an electric underfloor heating cost to run?

Electric underfloor heating feels luxurious and is lovely underfoot. It is also resistive heating spread across a whole floor, so the running cost scales with the area you have tiled. Every square metre is its own little heater, and they all draw at once.

At around 150W per square metre, even a modest bathroom adds up, and a large open-plan floor can become one of the most expensive things in the house to run. A 150W element per square metre is the same one-to-one resistive heating as a plug-in heater, just spread out flat, so the cost is driven simply by how many square metres you switch on and for how long.

It works best as gentle, scheduled comfort, not primary heating. Warm tiles in a bathroom for the morning routine, on a thermostat and timer so it is not heating an empty room all day. Used that way, over a small area for a couple of hours a day, the cost stays reasonable and the comfort is real.

The big mistake is treating electric underfloor as a whole-home heating solution. Running it across a large living area all day is where the bill gets frightening, because you are paying resistive rates to warm a large surface continuously.

A heat pump heats the same space for a fraction of the energy, because it multiplies its energy three-to-four times rather than converting it one-to-one. If you love the warm floor, the sensible pattern is to keep it zoned to small areas like the bathroom, tightly timed to the hours you are actually in there, and let a heat pump do the heavy lifting for the rest of the house.

Because the cost depends so directly on area and hours, this is one where the calculator is genuinely useful. Enter your heated floor area and the hours you run it at your own rate, and you will quickly see whether it is a pleasant small luxury or a hidden heavyweight, and how much a timer and a smaller heated zone would save.