Electricity used = fitted load in kW × hours actually heating. Cost = that kWh × your electricity unit rate. For an illustrative 10m² room with 7m² of fitted 150W/m² mats, the load is 1.05kW. At an example tariff of 28p/kWh, one full-power hour costs 29.4p. A thermostat can reduce on-time, but the actual demand depends on the room and conditions.
The calculation, in full
Take a 10m² room as the example.
This example assumes 7m² of fitted mats in a 10m² room. That is 70% coverage; it does not establish heating suitability. Check the room’s heat loss, floor specification and actual whole-mat layout separately.
The Ribbon produces 150W per m². Seven square metres at that output is 1,050 watts, or 1.05 kilowatts.
At 28p per kWh, used as a worked example, running continuously at full power for one hour costs 29p an hour.
This is the maximum energy charge for one full-power hour at the assumed tariff. A cold room may need sustained heating, so do not assume the thermostat will always reduce that figure.
How Thermostat On-Time Changes Consumption
The thermostat only calls for heat when the room needs it.
Say you schedule an hour before work and three hours after you get home. That is a four-hour schedule; actual full-power on-time may be shorter or may occupy the whole period, depending on heating demand.
If the room is already at the temperature you set, the heating does not come on at all, and for that period it costs nothing. If you set it higher, the system draws power to bring the room up, then switches off once it gets there and cycles on and off to hold it.
For illustration only, 15 minutes of full-power heating during an hour is a 25% duty cycle. Your system may run for less or more time depending on heat loss, weather, set temperature and its starting conditions. An EPC band does not establish a fixed duty cycle.
What that comes to in practice
| Room | A 10m² room |
| Illustrative fitted mat area | 7m², which is 70% of a 10m² room |
| Load | 1,050 watts, or 1.05 kilowatts |
| Electricity price used | 28p per kWh, used as a worked example |
| Maximum, flat out for an hour | 29p an hour |
| Example hour with 25% on-time | Just over 7p for that hour |
| A four-hour schedule at that duty cycle | Around 29p for the day |
| Four hours flat out, the ceiling | About £1.18 |
| A different room | Calculate from its fitted load and actual on-time |
| Supplier paperwork | Supplier paperwork includes Nemko certificate P15220551, dated 3 December 2015, for AHT floor-heating elements, Class II, tested against EN 60335-1, EN 60335-2-96 and EN 62233. Ask EkoBuild for the documentation applying to the product supplied. |
Work out your own
For a full-power hour, multiply fitted heated area in m² by 150 watts per m², divide by 1,000 to convert watts to kilowatts, then multiply by your electricity unit rate per kWh. That gives the energy cost of one full-power hour.
Multiply by the fraction of time the heating actually draws power. Use measured on-time where available; otherwise compare clearly labelled scenarios rather than assuming a universal duty cycle.
We are deliberately not publishing a single whole-house figure. It depends far too much on the individual property to be honest about, and a number that is wrong for your house is worse than no number at all. Per room, with the working shown, is the useful version.
Across the year
In summer it may not run at all, in spring and autumn only occasionally, and on the coldest winter days it will run for longer.
A well insulated room holds its heat longer than a poorly insulated one, so the thermostat calls for heat less often. That is why insulation and heat retention matter just as much as the price of electricity.
Solar panels and battery storage
The Ribbon runs on electricity, which means it can run on electricity you generated yourself. You cannot make your own gas.
During daylight, solar can supply the heating and cut what you buy from the grid. But most people need heat early morning and evening, when solar generation is low. A battery bridges that gap, and on the right tariff it can also charge on cheaper off-peak power.
Solar electricity is not free, the equipment has a cost and exported power has a value, but using your own generated or stored energy cuts how much heating electricity you buy at the full grid rate.
Solar and battery payback depends on installation cost, generation, demand and import/export tariffs. Use a property-specific assessment rather than a fixed payback period.
Is it cheaper than gas?
Here is the honest answer, and it is not the one you would expect a heating company to give.
Electricity costs more per unit than gas on a standard tariff, so it would be misleading to say electric is automatically cheaper. The comparison that matters is room-by-room control, fast response, no slab to heat, and solar, battery or off-peak on top.
Whether it works out cheaper in your house depends on its heat loss, floor construction, controls, tariff and how you use the heating. Ask for a room-specific assessment; a worked example is not a prediction of your bill.
Related video
This related clip covers solar and storage, not a complete running-cost calculation. Use the worked assumptions above for the cost example. How solar and storage can supply the heating: video, captions and transcript.
Get the number for your actual room
The free Room Designer works out the heated area, the coverage and the price for your room, so you are not working off an example.
Running cost FAQs
How much does electric underfloor heating cost to run per hour?
For the illustrative 7m² mat layout, 7 × 150W = 1.05kW. At 28p/kWh, a full-power hour costs 29.4p. If it draws power for only 15 minutes, that hour costs 7.35p; this is a scenario, not a typical-cost promise.
What does a room cost to run per day?
Using the same illustrative 1.05kW load at 28p/kWh, four full-power hours cost £1.176. Four scheduled hours at an assumed 25% on-time cost 29.4p. Actual on-time and your tariff determine the bill.
Is electric underfloor heating cheaper than gas?
Electricity costs more per unit than gas on a standard tariff, so it would be misleading to say electric is automatically cheaper. The comparison that matters is room-by-room control, fast response, no slab to heat, and solar, battery or off-peak on top.
Does it run all the time?
A thermostat calls for heat when needed. Actual on-time varies with the room, weather, chosen temperature and floor construction; it may remain on for a substantial part of a cold period.
How does solar change it?
Solar or stored electricity can reduce grid imports, but equipment cost, generation timing, losses and export value matter. Size the system and calculate payback using the property’s demand and actual tariff terms.
What electricity price are these figures based on?
28p per kWh is a worked example. For your own full-power hourly cost, multiply fitted heated area in m² by 150 watts per m², divide by 1,000, then multiply by your unit rate per kWh.