When it comes to long-standing green-living debates, washing up by hand versus using a dishwasher is right up there with hand-driers versus paper towels. Here are some carbon-footprint figures, which hopefully will put the issue to bed for once and for all.
Almost zero CO2e: by hand in cold water (but the plates aren't clean)
540g CO2e: by hand, using water sparingly and not too hot
770g CO2e: in a dishwasher at 55°C
990g CO2e: in a dishwasher at 65°C
8000g CO2e: by hand, with extravagant use of water
Source: How bad are Bananas? The carbon footprint of everything by Mike Berners-Lee
The Bonn University* identified that the majority of UK households are not careful when it came to using hot water sparingly when washing up – especially as many people wash up by hand under a hot running tap with the plug open. The evidence shows that a dishwasher can be on average far greener when used properly.
*Full details here
How can dishwashers be a greener option?
Most dishwashers manufactured since 1994 use less water per cycle than the equivalent required to wash up, because they recycle the water throughout the wash. Newer models heat only the amount of water they need - and being cold fill, the water is heated in the dishwasher itself, not in the household's hot water tank or central heating system, where heat gets lost in transit. A standard 60cm wide household dishwasher is designed to hold 12 or 14 place settings, while slim-line models, at just 45cm wide, will wash up to 8 place settings. This water and energy efficiency can also help lower your utility bills.
