Dishwashers

The dishwasher market is dominated by four companies, each with several different brands. In total these four accounted for almost 75% of sales in 2016. 

About 30% were from BSH Home Appliances (Bosch, Siemens, Neff and Gaggenau), 18% were from Whirlpool (Whirlpool, Hotpoint, KitchenAid, Maytag and Indesit), 14% from Electrolux (Electrolux, AEG and Zanussi), and 12% from Beko (selling Koç Group brands Beko, Blomberg, Flavel, Grundig and Leisure).

All of these best-sellers are in the bottom half of our Ethiscore table. All four company groups received a worst rating for supply chain management, and for their lack of conflict minerals policies, and all lost a whole mark for anti-social finance for having high risk subsidiaries in jurisdictions considered to be tax havens. 

The Whirlpool Corporation has also been the focus of serious concern over its failure to recall faulty tumble dryers which have caused fires in the UK. 

Dishwasher energy labels and ratings

Dishwasher EU energy labels range from A+++ (most efficient) to D (least efficient). The label includes information about drying efficiency and noise, as well as annual energy and water consumption (based on 280 cycles/year or around five per week).

We gave an extra half mark to a brand if it had at least one A+++ model of dishwasher available on its website. With some brands, all models were A+++ rated. But nearly half the brands on the table had no A+++ models.

How do dishwashers compare to washing up?

The first question ethical consumers generally ask about dishwashers is: are they more energy efficient than washing up by hand? Studies tend to conclude that dishwashers win. Modern dishwashers can be so efficient with their use of hot water that they can beat all but the most frugal of washer-uppers.

The second question is: does this include the energy used to manufacture the machine in the first place? It does: the embedded energy accounts for less than 10% of that used over the lifetime of the product. 

However, it is worth noting that all the studies show that the amount of energy and water used depends a lot on how you do the job. Most importantly, they find huge variation in how much hot water people use to wash up by hand. Modern dishwashers use about 10 litres per cycle.

In a 2011 global comparison (which did not include the UK), the average amount of water used to wash 140 items by hand ranged from 34.7 litres in Australia to 160 litres in Russia. Individuals used between 18 to 473 litres! It seems like some people do their dishes in the bath. 

How much energy would you save using a dishwasher? 

In a 2010 study, the average hand-washer in the UK used 49 litres of water and 1.7 kWh of energy for a load, compared to 13 litres of water and 1.3 kWh of energy used by the dishwasher. (The difference in energy was not as great as the difference in water, due to people using cold water as well as hot).

The average Brit uses about 35 MWh of energy per year in total, so if you washed up once a day, this 0.4 kWh daily saving would be slightly less than half a percent of your energy usage. 

That isn’t nothing, but it should probably be considered to be at the upper end of what you might achieve. The dishwasher used in the comparison was set to an Eco cycle which only heated water to 50 degrees, lower than many standard dishwasher cycles.An Eco cycle may take longer and will not be everyone's first choice.

Also, the study did not include any pre-rinsing, which many people do, and which can add 10-20 litres per cycle. Dishwashers can also encourage people to use items only once, where otherwise they might reuse them before washing, particularly mugs and glasses. 

So should I buy a dishwasher if I'm concerned about energy use?

It is likely that you can save some energy and water by using a dishwasher, if you use it in the most efficient way. Full size machines (12-14 place settings) are more efficient than compact (6 settings) or slimline machines (10 settings). 

However, if you are in a household of one or two people, and wash up very efficiently, the case for a dishwasher is less compelling than in a larger household. 

And even in terms of how much water you heat in your house, there may be more effective changes you could make. Only 1% of the average UK home’s heated water use is for a dishwasher, or 4% for washing up, compared to 9% for baths, and 25% for showers. 

If you do have a dishwasher, keep it in good repair 

• Weekly - clean the filter 
• Weekly - wipe the door seals – to prevent perishing leading to leaks
• Every 6 months - remove and clean the spray arms
• Every 6 Months - run a hot cycle on empty to stop any smells.