How much electricity does a dishwasher use?

With an ongoing energy crisis and bills rocketing, it’s useful to know how much energy our appliances are using. What about the humble dishwasher? How much electricity does a dishwasher use?

Finding an energy-efficient dishwasher

If you’re in the market for a dishwasher, then make sure to pay attention to the energy efficiency rating. Dishwasher energy ratings go from A+++ to D and the largest dishwashers are generally the most efficient.

Dishwasher energy labels provide an estimate of annual energy consumption, though the accuracy of this will depend on how regularly you use it. The annual energy consumption estimate is based on 280 standard wash cycles per year, which is about 5 washes a week. 

One of the main components which affects a machine’s efficiency is the inverter motor. Look for dishwashers with brushless motors as they’re quieter and more efficient.

Also, your individual habits will make a big impact on the actual amount of power your dishwasher uses but, nevertheless, multiplying the annual energy consumption of a dishwasher with the cost of electricity per kWh that you pay will give you a good estimate of how much it will cost to run that appliance year-round. 

If you look up your unit rate for your current energy company then this will tell you how much you pay per kWh. If you have an off-peak tariff of some kind (e.g. Economy 7) then you’ll need to know that too. For me, my peak rate is 37.67p per Kilowatt hour and off-peak is 21.89p per Kilowatt hour at the time of writing. If we take an example dishwasher, currently on sale at Currys, it has an energy rating of E and an energy consumption of 0.92 kWh per use (of course, bear in mind that this will vary considerably depending on the type of wash cycle that you use). This would mean an energy cost of 35p during peak rate and 20p off-peak.

One value forgotten about is ongoing energy use. For example, this Kenwood dishwasher consumes 0.5W when switched off and 1W in standby. To work out how wattage applies to kWh you can use an online calculator. So, if you use this dishwasher off-peak, so it’s in standby (turned on but not washing) for six hours a day and off for the remaining 16, that would use 14W, or around another 0.5p a day. Not a great deal but worthy of consideration. It also begs the question why a dishwasher needs to consume power when switched off!

How much electricity is my current dishwasher using?

This is something you’ll need to find out from your manufacturer (or the instructions manual, if you still have it). Most dishwashers will have a label on them listing the model number and you can use that to look up your specific details.

Apply the same rules as above and you can quickly work out your energy use.

Using my own rates above, I applied them to an A rated dishwasher (a Miele at 0.540 kWh per cycle) and to an F rated model (a Samsung dishwasher at 1.4 kWh per cycle). This gives a price range of 12p (31p at off-peak) and 20p (51p at peak rate) per cycle, which should give you an idea of the typical cost range.

Is it worth using a dishwasher over hand washing?

This is a tricky calculation, because it depends on several factors, including water usage. Don’t forget too that you may be comparing electricity costs of the dishwasher versus the gas costs of heating water for a sink of water. How the water in your house is heated is a factor too, so it’s hard to making a sweeping comparison that fits everyone.

Which magazine has calculated that you only need 13 items in your dishwasher for it to be more water efficient than hand washing, so as long as you have that you should consider the dishwasher over a bowl of soapy water (at least in terms of water, not electricity consumption).

But, do whatever you can to limit its use:

• If you have Economy 7 or any other cheap-rate electricity, switch on your dishwasher during these hours
• Wait until the dishwasher is as full as possible before putting it on
• Make use of any eco-wash options that your dishwasher has; the longer cycles are (counterintuitively) often the most energy efficient
• Regularly use dishwasher cleaners and make sure you clean out filters, etc – this will ensure it runs as efficiently as possible
• Cheap dishwasher tablets can, equally, be a false economy if they don’t wash your dishes sufficiently. If using any kind of review site, be wary of tablets having high ratings because they’re cheaper rather than actually clean well, which is often the case