Use the calculator below to estimate electric heater cost per hour (fan heater, convector, oil-filled radiator, panel heater) or gas heating cost per hour for a boiler heating the home.
Enter the unit rate from your tariff, then adjust the power and hours to match how you actually heat your home in the evenings.
The results are most useful when you compare options like “one room electric heater” versus “whole home gas heating” using the same daily hours.

How to interpret the “per hour” heating cost

The number that matters most is the heating cost per hour, because it makes different heating choices comparable.
A 2kW electric heater can look “cheap” until you see the electric heater cost per hour multiplied by three or four hours every evening.
In contrast, gas central heating is a whole-house system, so the hourly figure is more about what the boiler is burning while it is actively heating, not a single appliance.

Real homes rarely heat in a perfectly steady line. Boilers cycle, rooms reach temperature at different speeds, and heat loss varies by room.
That is why the cleanest comparison is always “same comfort outcome”: one person in one room versus trying to raise the temperature everywhere.
If you are weighing those two approaches, the comparison in Heated Blanket vs Electric Heater explains why personal warmth is often the cheapest way to stay comfortable.

Why your real heating cost can be higher than the calculator

If your result looks low but your bills feel high, it is usually because the heating is running longer than you think, or because the house cannot hold onto the warmth you are paying for.
The most common pattern is a heater or boiler effectively “chasing” heat loss, especially in draughty rooms, hallways, and rooms with cold floors or weak insulation.
When heat disappears quickly after the heating stops, it can make any heating method feel expensive because you are repeatedly reheating the same cold structure.

For central heating, another hidden driver of cost is distribution. If some radiators overheat while others lag, you often end up extending heating time just to make one area tolerable.
When flow is shared properly across the circuit, comfort tends to arrive sooner and the boiler can run more steadily rather than constantly compensating for imbalance.

Use the calculator as part of a whole-home approach

This calculator is best used as a decision tool: it tells you what your chosen heating method costs to run at your unit rate, for your hours, in a way you can compare side by side.
The next step is making sure the heat you pay for actually stays where you need it.
That wider strategy is explained in How to Keep a UK Home Warm for Cheap, which ties together heat loss, radiator performance, and targeted warmth so comfort improves without simply turning everything up.