Save Energy in Washing up 
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Some people love doing it, but I’m afraid I’m not one of them. And neither’s my wife. Surely the Dishwasher is the best domestic appliance of all time…
So an important question to all those like us is how does the dishwasher stack up in terms of Carbon footprint ? Is it true that it's greener than doing the dishes by hand ?
Well, let’s say it actually might be.
It all depends. If you’ve got a modern machine, only run it with a full load and do so at a low temperature you may well be greener. This is because a modern dishwasher is so efficient with the water it uses. Older models tend to be a lot more consumptive.
DISHWASHER - HOW IT WORKS:
A dishwasher is actually a very simple machine. First it heats up a load of water, then sprays that around from a spinning jet onto all the dirty dishes. Once done it pumps out the dirty water and gives the dishes a rinse. When that’s pumped away you’re done. Unless you’ve got one that blows hot air over the dishes to dry them.
Of all these things, heating the water is far and away the greatest consumer of energy.
POSITIVE STEPS:
Full load:
Like a washing machine, dishwashers use a very similar amount of energy whether full or empty. If you’re putting it on just to wash the coffee mugs it’s not going to be a very efficient use of energy. Instead, wait until you have a good full load before switching on to be most Carbon-efficient.
Lower temperature:
Given that a dishwasher uses most of its energy in heating up water, if you can drop the temperature it is bound to help. Turn it to the lowest setting and see. In a machine we looked at, just dropping it by 10degrees saved around a quarter of its electricity.
Eco-setting
Some machines have an “economy” or “quick wash” setting. It’s well worth checking out how that performs as you could save more. If you have the manual it should tell you how much energy it will save. Like on the washing machine, there’s often no perceptible difference in quality of wash on these settings… just much better energy efficiency… and that means less Carbon.
Get the best rated machine
These days the efficiency of dishwashers is many times better than it used to be. Some will now wash a loadful using less than 1 kWh and only 10 litres of water. So as and when you do need a new one, make sure that you look out for the top rated ones.
Hot water feed
In the past dishwashers had a hot and cold feed, but these days many machines have just a cold water input. Although probably done for reasons of cost, this is an environmental step backwards as it means the hot water has to be heated by electricity rather than from your own domestic supply. Doing so is far less energy-efficient.
For instance heating a litre of water up by gas rather than by average UK electricity produces 2.5 times less CO2. And if you have solar hot water on tap then you’re infinitely better off in terms of Carbon. If you can get a system with hot and cold fill then great. The other alternative, as ever, is to ensure that your electricity is as low Carbon as possible.
What about HAND WASHING ?
If you’re washing by hand, the same principles apply.
Full load:
Washing a sink-full of dishes is much more energy efficient than doing them in dribs and drabs.
Plug in:
Keep the hot water in the sink to let things soak in while other things are being washed. Once done, they then only need a light rinse with minimal scrubbing. Anything that speeds up washing up has got to be a good thing in my book !
Bowl:
If you’re not likely to fill the sink, use a washing-up bowl instead. This will instantly cut down the volume of the hot water you need while still giving dirties a chance of a good soak.
