Run the dishwasher on eco — and only when it's full
A modern dishwasher run full on the eco cycle beats hand-washing on both water and energy. The trick is to resist part-loads and skip the rinse-under-the-tap habit.
It feels virtuous to wash up by hand, but the numbers usually disagree. A full modern dishwasher on its eco setting uses only around 6–10 litres of water for an entire load, while hand-washing the same dishes under a running tap can easily get through several times that — plus the energy to heat all of it. The machine recirculates a small amount of water and heats it precisely, which is hard to beat at a sink.
The two habits that make or break it are running it full and choosing eco. A half-empty machine throws away the advantage, so it pays to wait until it’s properly loaded. And eco, despite its long run time, is the efficient choice: it saves energy by heating less water more slowly, rather than the quick cycle’s short blast of very hot water. The long clock is the point, not a problem.
The classic mistake is pre-rinsing every plate under the tap “to be safe” — that single habit can pour away more water than the whole cycle uses, and modern detergents are formulated to grip onto food residue, so they actually clean better when there’s something to grab. Scrape, don’t rinse; load it full; press eco. It’s a rare case where the lazier, greener and cheaper options all line up.
How to do it
- Always select the 'Eco' programme as your default — it uses less water and heats it more gently over a longer run, which is where the saving comes from.
- Only run the machine when it's genuinely full — stack smartly so nothing blocks the spray arms, rather than running it half-empty out of habit.
- Scrape plates into the bin or compost instead of pre-rinsing under the tap — modern detergents and machines handle the rest, and pre-rinsing can waste more water than the whole cycle saves.
- Use the right detergent and keep the salt and rinse-aid topped up so eco's lower temperature still cleans well and the machine doesn't scale up.
- If you have a time-of-use or cheaper night tariff, use the delay-start timer to run the cycle when electricity is cheapest or greenest.
Pro tips & pitfalls
- Eco takes longer than the quick cycle precisely because it saves — it heats less water more slowly rather than blasting it hot and fast. Don't let the long run time tempt you back to the intensive programme; the clock running doesn't mean energy is pouring in.
- Clean the filter and wipe the door seal every week or two — a clogged filter makes the machine work harder and leaves dishes needing a rewash, which undoes the saving.
What it's good for
Good for the planet
- Saves water A full eco cycle uses only around 6–10 litres for a whole load — far less than the tens of litres a tap pours while hand-washing the same dishes.
- Saves energy Eco heats less water and heats it gently, so it's the lowest-energy programme on the machine — and a full load means fewer cycles overall.
Good for you
- Saves money Less hot water heated means lower water and energy bills; running full and on eco, rather than hot quick-cycles or hand-washing, typically saves a household €20–60 a year.
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