The short answer
The appliances that use the most electricity are usually the ones that heat air or water, run for a long time, or stay switched on all day. That is why tumble dryers, washing machines, dishwashers, electric heaters, ovens, fridges and freezers are often worth checking first.
There is no single appliance ranking that fits every home. A tumble dryer may be expensive per cycle, but a fridge-freezer is on all day. A kettle is high wattage, but only runs for minutes. The real cost is not just “how powerful is it?” — it is power multiplied by time, then multiplied by your electricity rate.
This guide shows the appliances to check first, explains how to calculate running cost using kWh, and links each decision back to the Calculatorz electricity tools.
Appliances most likely to use the most electricity
Energy Saving Trust says washing machines, dishwashers and tumble dryers account for 14% of a typical energy bill because they need electricity to heat water or air. It also highlights fridges and freezers because they are switched on 24 hours a day.
Tumble dryer
High power and long running time can make drying clothes one of the biggest appliance costs.
Washing machine
Heating water increases electricity use, especially on hotter washes or frequent cycles.
Dishwasher
Uses electricity for heating water and drying; full loads usually make better use of each cycle.
Fridge-freezer
Power draw cycles up and down, but the appliance runs day and night.
Electric heater
Often high wattage. Long evening use can quickly add to electricity costs.
Kettle, oven and hob
Some are high wattage, but cost depends on how long they are used and how often.
How appliance electricity cost is calculated
Electricity cost comes from wattage, usage time and your unit rate. The current Calculatorz default is 26.11p/kWh, based on Ofgem average Direct Debit electricity rates for 1 July to 30 September 2026, but you should use your own tariff for accuracy.
kilowatts = watts ÷ 1,000
kWh used = kilowatts × hours used
cost = kWh used × electricity unit rate
Appliance cost priority table
Use this table as a priority order. It is not a fixed ranking for every home, but it tells you which appliances are most worth measuring.
| Appliance | Why it can cost more | What to check | Best action |
|---|---|---|---|
| Tumble dryer | Uses heat and runs for long cycles. | Cycle length, power rating, filter cleaning and usage frequency. | Air dry when practical, keep filters clean and avoid half-load drying. |
| Washing machine | Heating water can increase cost. | Temperature, cycle length and number of weekly loads. | Use full loads and lower-temperature washes where suitable. |
| Dishwasher | Uses hot water and drying heat. | Eco mode, full loads and drying settings. | Run full loads and use efficient settings. |
| Fridge-freezer | Runs 24 hours a day. | Age, energy label, temperature, seals and frost build-up. | Keep seals clean, avoid overfilling and replace inefficient old units when justified. |
| Electric heater | High wattage and long use can be expensive. | Wattage, hours used and whether central heating would be cheaper. | Use targeted heating carefully and improve insulation or draught-proofing. |
| Oven, hob and kettle | High power, but usually shorter use. | Cooking time, batch cooking and how much water is boiled. | Only boil what you need and choose suitable cooking methods. |
| TVs, consoles and computers | Moderate power, but long hours and standby add up. | Daily hours, screen size, standby and charging habits. | Turn off fully when not needed and avoid leaving devices idle. |
| Lighting | Lots of bulbs across many rooms can add up. | Old halogen/incandescent bulbs, wattage and hours used. | Switch to LED and turn off unused lights. |
Why tumble dryers are often near the top
Tumble dryers combine the two things that make electricity costs rise: heat and time. A dryer cycle can run for a long period, and the appliance uses energy to produce warm air.
Energy Saving Trust’s quick tips put avoiding the tumble dryer near the top of its at-a-glance savings list. The saving depends on how often you use it and what you do instead.
Count weekly cycles
One cycle a week and seven cycles a week are completely different energy problems.
Check drying time
Longer cycles cost more. Overloading, blocked filters and damp rooms can make drying less efficient.
Compare alternatives safely
Outdoor drying is usually cheapest, but indoor drying needs ventilation to avoid damp problems.
Washing machines and dishwashers
Washing machines and dishwashers matter because they use electricity to heat water. Running more cycles than needed, washing at higher temperatures, or using half loads can increase cost.
Energy Saving Trust advises using fewer, colder washes and filling the dishwasher. It also notes that doing one fewer load of washing a week and washing at 30°C can save money.
Best first checks
Use full loads where practical, choose eco or lower-temperature settings when suitable, and compare your actual weekly cycles in the calculator rather than relying on generic averages.
Fridges and freezers: lower power, long hours
A fridge-freezer may not look dramatic on wattage alone, but it is switched on all day. That makes age, efficiency, temperature settings, door seals and frost build-up important.
Energy Saving Trust says fridges, freezers and fridge-freezers are among the longest-lasting appliances in our homes, so it can be worth choosing efficient models when replacement is due.
Do not judge by wattage alone
A high-wattage appliance used briefly may cost less than a lower-wattage appliance used all day. Always multiply power by time.
Electric heaters, heated airers and plug-in heating
Electric heaters can be useful for short, targeted heating, but long use can be costly. The same logic applies to heated airers, heated throws, dehumidifiers and other plug-in heating or drying devices.
The decision is not simply “electric heater bad”. It depends on wattage, hours used, room size, insulation, central heating alternative and whether you are heating one person, one room or the whole home.
Kitchen appliances: kettle, oven, hob and microwave
Kitchen appliances often use high power, but many run for short bursts. That means behaviour matters. A kettle can be cheap or wasteful depending on how much water you boil and how often you boil it.
Energy Saving Trust’s quick tips include not overfilling the kettle. Its kitchen advice also recommends letting hot food cool before putting it in the fridge or freezer, defrosting freezers, and avoiding leaving fridge or freezer doors open for long periods.
Lighting, standby and small devices
Lighting and standby power are rarely the only reason for a large bill, but they are easy to improve. Many small costs become noticeable when they happen every day across multiple rooms and devices.
Ofgem says changing old bulbs to efficient LED lights can save up to £4 per bulb per year, based on Energy Saving Trust guidance. Energy Saving Trust also says switching appliances off at the plug can save around £45 a year in Great Britain.
Calculate LED savings
Compare old bulb wattage with LED wattage, hours of use and purchase cost.
How to measure your own appliance use
The most accurate way to find your expensive appliances is to measure or calculate your own usage. Citizens Advice provides an appliance calculator to compare electrical appliance costs, and Calculatorz lets you run your own wattage and usage assumptions.
- Find the appliance wattage on the label, manual or manufacturer website.
- Estimate realistic hours per day or cycles per week.
- Use your own electricity unit rate from your bill.
- Calculate weekly, monthly and annual cost.
- Compare the saving with the cost of changing behaviour or replacing the appliance.
A smart meter or plug-in energy monitor can help you spot usage patterns, but you still need to connect the reading to habits and appliance use.
Should you replace an appliance to save electricity?
Replacing an appliance only makes financial sense if the saving justifies the purchase cost. A new efficient fridge-freezer may save energy, but buying one too early may not be the best use of money.
| Before replacing | Ask this | Why it matters |
|---|---|---|
| Annual running cost | What does the current appliance cost per year? | You need a baseline before judging savings. |
| New appliance cost | How much will the replacement cost? | Purchase cost can outweigh annual savings. |
| Payback period | How many years until savings cover the purchase? | A long payback may not justify early replacement. |
| Behaviour change | Can you reduce usage without replacing it? | Sometimes habit changes give faster savings. |
Estimate your whole bill impact
Appliance savings are useful, but your full bill also includes standing charges and gas usage.
Common appliance-cost mistakes
- Judging cost by wattage without considering hours used.
- Ignoring always-on appliances like fridges and freezers.
- Using national averages instead of your own tariff and usage.
- Replacing appliances before calculating payback.
- Forgetting that your bill also includes standing charges.
- Assuming a “small” device cannot add up if it runs for many hours.
- Leaving old bulbs in rooms used for long periods.
FAQs
Which appliance uses the most electricity?
It depends on your home, but tumble dryers, washing machines, dishwashers, electric heaters, ovens, fridges and freezers are usually worth checking first.
How do I calculate appliance running cost?
Divide watts by 1,000, multiply by hours used, then multiply by your electricity unit rate.
Is a tumble dryer expensive to run?
It can be, because it uses heat and often runs for a long cycle. The exact cost depends on wattage, cycle length and your electricity rate.
Are fridges and freezers expensive?
They can be significant because they run all day. Age, efficiency rating, seals, frost and temperature settings affect running cost.
Should I replace old appliances?
Only after comparing the new purchase cost with the annual running-cost saving. Sometimes usage changes pay back faster than replacement.