Heating, cost per kWh
What a kWh really costs, once the standing charge is in
Every figure on this site is priced at the capped unit rate, and the bar at the top of every page says so. That rate is not what a kilowatt hour costs you. The standing charge is payable whether you use anything or not, and once it is spread across the units you actually buy, the same tariff costs one household half again what it costs another.
Some links on this page are affiliate links, which earn us a commission if you buy. It costs you nothing extra, and it never changes which option comes out cheapest here, because the ranking is arithmetic. How this works.
The unit rate is not the price
The cap sets a unit rate of 26.11p per kWh for electricity and a daily standing charge on top. The standing charge is not a fee for using energy, it is a fee for being connected, and you pay it on a day you use nothing at all. Divide a year of it across the units you actually buy and it becomes part of the price of every one of them.
| Option | Running | Cost per kWh | Relative |
|---|---|---|---|
| Mains gastypical use, 11,500 kWh | 7.33p | 8.25p | |
| Off-peak electricityovernight rate, 2,700 kWh | 7p | 14.7p | |
| Electricity, high use4,200 kWh a year | 26.1p | 31.1p | |
| Electricity, typical use2,700 kWh a year | 26.1p | 33.8p | |
| Electricity, low use1,800 kWh a year | 26.1p | 37.7p |
The spread is 4.6 to one between mains gas and electricity, low use, on identical tariffs, with nobody switching anything. The only difference is how much each household buys.
Why the low user pays the most
This is the part that reads as unfair, because it is. The standing charge is a fixed annual cost of roughly two hundred pounds across both fuels. A household buying 4,200 kilowatt hours of electricity spreads that over a lot of units. A household buying 1,800 spreads the same money over far fewer, so each one costs more. Using less energy saves you money in total and raises what you pay per unit, at the same time.
Work out your own figure before reading any tariff comparison. Take the annual kilowatt hours off a bill, add the standing charge for the year, divide by the kilowatt hours. That number, not the headline unit rate, is what a switch has to beat. A tariff advertising a lower unit rate and a higher standing charge can easily cost a low user more.
Gas is not slightly cheaper, it is a different order of thing
Per kilowatt hour delivered into the meter, gas costs a small fraction of what electricity costs, and that gap is wider than any tariff decision available to you. It is the single most important number in a British house, and it explains why heating with a plug-in electric heater costs so much more than heating with a boiler, and why a heat pump has to be about three times as efficient as a boiler merely to draw level.
It also sets a floor under the electric options on this site. Even the off-peak overnight rate, which is the cheapest electricity most people can buy, is still dearer per unit than mains gas. Anywhere on this site where an electric appliance loses to a gas one, this table is the reason.
Where the working comes from
There is no purchase price and no consumable here, so the sum is unusually short: the capped unit rate, plus the daily standing charge times 365, divided by the units bought in a year. Both the unit rates and the standing charges are the current Ofgem cap and update themselves on this site when the cap changes.
The verdict
If you use a lot of energy, the unit rate is most of your price and shopping on unit rate is sensible. If you use very little, the standing charge is most of your price, the unit rate matters less than the advertising suggests, and the saving available from switching is smaller than it looks. Either way, heat with gas rather than electricity wherever you have the choice, because no tariff on the market closes a gap that wide.
Put your own numbers in
Change the kilowatt hours a year to your own annual figure, taken off a bill rather than guessed, because that single input is what this whole page turns on.
Cost per meal
Set the purchase price to zero for the running cost alone.
Questions
What does one kWh of electricity actually cost in the UK?
Between 8.25p and 37.7p on the figures in this page, depending on how much you buy. The capped unit rate is 26.11p per kWh, and the rest is the standing charge spread across the units you use.
Why do I pay more per kWh if I use less energy?
Because the standing charge is fixed. It is charged for being connected rather than for what you use, so the fewer units you buy, the larger the share of it that lands on each one. Using less still lowers your total bill.
Is gas cheaper than electricity per kWh?
By a wide margin, and the gap is bigger than any tariff switch. That is why a plug-in electric heater costs several times what a gas boiler costs to deliver the same heat, and why a heat pump needs to be roughly three times as efficient as a boiler just to draw level.
Should I switch to a fixed tariff?
Work out your own cost per kWh first, using your annual kilowatt hours and the standing charge, because that is the number a fixed deal has to beat. A lower unit rate paired with a higher standing charge can cost a low user more. A fix is also a bet on where prices go next rather than a saving in itself.
Does the price cap cap my bill?
No. It caps the unit rate and the standing charge, not the total. If you use more, you pay more, and there is no ceiling on the bill itself.
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More heating and damp costs, or read how we work these out.
Prices used on this page
- Electricity, 26.11p per kWh. Ofgem price cap, direct debit, average of England, Scotland and Wales, including 5% VAT.. Ofgem energy price cap unit rates and standing charges. Checked 22 August 2026.