Ask most people what is driving their electricity bill and the answer comes back as lights left on, the television, or a phone charger forgotten in the wall. Those guesses are nearly always wrong. The things that actually empty a UK electricity bill are the appliances that make heat, because turning electricity into warmth takes a great deal of energy. A bulb sips power; a kettle gulps it. This guide ranks where the money really goes in a typical home, explains why a two minute job can cost more than a gadget left on all day, and shows you how to pin down your own biggest users rather than guessing.
The short answer. Anything that heats water or air is the big spender: electric showers, immersion heaters, kettles, washing machines and tumble dryers, ovens and electric heaters. Cold appliances (fridges and freezers) cost a fair bit too, not because they pull much power but because they never switch off. Lighting, televisions, laptops and chargers are usually a small slice of the bill, even in a house full of them. If you want to cut the bill, start with the heat, not the gadgets.
The rule that explains your whole bill: heat is expensive
Every appliance has a power rating in watts, and your bill is set by that power multiplied by the hours it runs. The catch is that the appliances which make heat draw enormous power compared with everything else. An LED bulb might draw 8 watts. A laptop draws perhaps 50 watts while charging. A kettle draws around 3,000 watts, an electric shower 8,500 to 10,500 watts, and a tumble dryer 2,500 watts. Heat-making appliances are simply in a different league, often hundreds of times hungrier than the electronics people worry about.
That is why the famous advice to switch off a standby light or unplug a charger barely shows up on the bill, while a long daily shower or a few tumble dryer loads a week genuinely does. The principle behind all of it is the kilowatt hour, the unit your meter counts and your supplier charges for; if that is not yet second nature, our explainer on what a kWh is walks through the sums slowly. Once you think in kWh, the ranking below stops being surprising and starts being obvious.
The biggest users, ranked
Here is a rough ranking for a typical home, with illustrative daily costs at an example price of 26p per kWh. Your own figures will differ with how long you run each appliance, but the order rarely changes.
| Appliance | Typical power | Illustrative cost in use |
|---|---|---|
| Electric shower | 8.5 to 10.5 kW | about 40p to 55p per 10 minutes |
| Immersion heater | 3 kW | about 78p per hour |
| Tumble dryer (vented or condenser) | 2.5 kW | about 90p to £1.30 per cycle |
| Oven | 2 to 2.5 kW | about 50p to 80p per hour of cooking |
| Electric heater | 2 kW | about 52p per hour |
| Washing machine | 0.5 to 2 kW (mostly the heat) | about 20p to 50p per cycle |
| Kettle | 3 kW | about 2.5p per boil |
| Fridge freezer | tiny, but always on | about 20p to 40p per day |
| Television | 50 to 120 W | about 1p to 3p per evening |
| LED lighting (whole house) | a few watts each | a few pence per day |
Illustrative figures at an example 26p per kWh to show the order of magnitude, not a quote. Actual costs depend on the model and how long you run it.
Notice how the kettle, despite a scary 3 kW rating, costs almost nothing per boil because it runs for under three minutes. Power alone does not decide the bill; power multiplied by time does. The expensive items are the ones that combine high power with real running time, which is why showers, immersion heaters and dryers sit at the top.
Heating water: the quiet giant
For most homes, heating water is the single largest electrical cost after space heating, and it hides in plain sight. An electric shower is effectively a small instant water heater bolted to the wall, pulling around 9 kW while it runs. Two ten minute showers a day, every day, can add up to a meaningful chunk of the bill on their own. The fix is rarely to shower less; it is to shower for less time and at a slightly lower flow, which our guide to electric shower running costs works through with numbers.
The immersion heater is the other water heavyweight. A 3 kW element heating a full cylinder can run for a couple of hours to bring a tank up to temperature, so an hour or two a day quietly becomes one of the larger lines on the bill. If you rely on an immersion rather than a gas boiler for hot water, the timing and the cylinder insulation matter a great deal; see immersion heater costs for how to run it cheaply, ideally on a cheaper overnight rate if you have one.
Heating rooms with electricity: the most expensive habit of all
If you heat any part of the home with plug-in electric heaters, that will usually dwarf everything else here. A single 2 kW heater costs around 52p an hour at the example rate, so running one through a cold evening costs a few pounds, and running several around the house turns into the biggest item on the bill by a wide margin. Electric heating is not inefficient (almost all the energy becomes heat), it is just that electricity itself is dear per kWh compared with gas. People reach for a portable heater thinking it is the frugal option and end up spending far more than running the central heating would have. The trade-offs are laid out in gas versus electric heating costs.
The kitchen: short bursts, high power
The kitchen is full of high-wattage appliances, but most run only briefly, so the cost depends entirely on how long the heat is on. The oven is the kitchen's biggest user because it stays hot for an hour or more, holding a couple of kilowatts the whole time. A hob, a microwave or an air fryer used for a quick job costs far less. The washing machine looks like a modest user until you realise that almost all its electricity goes into heating the water, which is why dropping the temperature makes such a difference, and why the tumble dryer, which has to evaporate water out of soaking clothes, is one of the priciest appliances most homes own. Drying clothes on a rack or line instead, when you can, sidesteps that cost entirely.
Cold appliances and the always-on background load
Fridges and freezers are a different kind of cost. Each one draws very little at any moment, but it runs every hour of every day all year, so the small numbers accumulate. A single fridge freezer might use somewhere between 200 and 400 kWh a year, which is real money even though you never see it spike. An old, poorly sealed or badly sited unit can use far more, so this is one of the few cases where the age and condition of an appliance, not your behaviour, drives the bill.
Then there is the background hum of a modern home: the broadband router, the smart speakers, the television on standby, the boiler's controls, the doorbell, the phone chargers. Individually these are tiny. Added together they form a constant baseline load that runs day and night, and while no single one is worth chasing, the total can be 10 per cent or so of a household's electricity. In practice, switching off a few of them saves pennies, but understanding the baseline helps you read your bill; our guide to standby power separates the items worth switching from the ones not worth the bother.
How to find your own biggest users
General rankings only get you so far, because your home is not average. The reliable way to know what is costing you is to measure. A plug-in energy monitor, a cheap device that sits between an appliance and the socket, tells you exactly what that appliance draws and what it costs over a day or a week. Put it on the tumble dryer, the fridge, the games console, anything you are unsure about, and the guesswork disappears. Our guide to using a plug-in energy monitor explains how to read one.
For the things that cannot be unplugged, like an electric shower or a hardwired cooker, the appliance ranking and a bit of arithmetic do the job: power in kW, multiplied by hours used, multiplied by your unit rate. You can run those numbers for any appliance in seconds with the running-cost calculator, which is the fastest way to turn a vague worry into a real figure and decide whether it is worth acting on.
The bottom line
The electricity bill is dominated by heat, not gadgets. Showers, immersion heaters, electric room heaters, ovens, washing machines and tumble dryers are where the money goes, because they combine high power with real running time. Cold appliances cost a steady amount simply by never switching off, and the always-on background load is a small but constant baseline. Lighting and electronics, the things people instinctively blame, are usually a minor part of the total. So if you want a smaller bill, spend your effort on shorter showers, cooler washes, line drying, and being careful with electric heating, and measure anything you are unsure about rather than guessing. Start with the running-cost calculator to see your own numbers.