How Much Do Household Appliances Cost to Run?
Some appliances cost pennies to run and others add up to a large share of your bill. Knowing which is which helps you decide where to cut back. The calculation is the same for every electrical appliance, and you only need three numbers.
The formula
Cost = power in kilowatts × hours used × unit rate. To convert watts to kilowatts, divide by 1,000. For example, a 2,000 watt heater is 2 kW. Run for three hours, it uses 6 kWh. If your electricity rate is expressed in pence per kWh, multiply 6 by that rate to get the cost in pence, then divide by 100 for pounds.
You can try this with our appliance cost calculator, which does the sums for you using your own unit rate.
Where to find the power rating
Look for a label on the back or underside of the appliance, or in the manual, showing watts (W) or kilowatts (kW). Many devices also show amps and volts. Multiply them to estimate watts. For devices that cycle on and off, such as fridges, the label rating overstates the average use.
High-power appliances used in short bursts
- Kettles typically draw around 2,000 to 3,000 watts but only for a few minutes at a time. Boil only the water you need.
- Ovens and hobs use a lot per hour but vary with how long you cook. Using the right size ring and a lid saves energy.
- Microwaves are usually more efficient than ovens for small portions.
- Electric showers are among the highest-power household devices, so shorter showers make a real difference.
Appliances that run for long periods
- Portable electric heaters are typically 1,000 to 3,000 watts and expensive when left on for hours. Heat the room you are using, not the whole home.
- Tumble dryers are one of the most energy-hungry appliances. Air-drying when you can saves a lot. A heat pump dryer uses far less than a vented one.
- Dehumidifiers can be useful in damp homes but run for hours. Fix the cause of moisture where you can.
Always-on devices
Fridges, freezers, broadband routers and devices on standby use little power each but run all year. Over twelve months, their total can be surprisingly large. A fridge freezer in good condition and at the right temperature is efficient, whereas an old or overfilled one works harder. Switching off devices left on standby, or using a smart plug, can trim your usage. See our guide to smart plugs and energy monitors.
Lighting
LED bulbs use a fraction of the power of old halogen or incandescent bulbs and last far longer. Replacing the bulbs you use most is one of the cheapest upgrades in the home.
Measuring rather than guessing
A plug-in energy monitor tells you exactly how much an appliance uses over time, including standby. It is the best way to find out what an old appliance really costs and whether replacing it would pay off. Once you know your main energy users, you can focus your effort where it counts.