Four hours in the dishwasher cost less than one

A dishwasher's motor uses very little: almost the whole bill goes on heating the water. That is why the European energy label, compulsory in its current form since March 2021, measures the eco programme and not the quick one. Three numbers you will find in the manual of any modern machine:

1. Temperature. Eco washes at around 50 °C; the quick cycle at 65 or 70. Every degree is paid for.

2. Time. Eco runs for three to four hours because it makes up for lukewarm water by letting the detergent work much longer. The heating element is only on for a few minutes of all that time; the rest is waiting.

3. Consumption. An eco cycle uses about 0.75 kWh; a short programme climbs to 1.3 or 1.5. Running it daily, the gap comes to more than 200 kWh a year, as much as a small fridge.

The quick programme has its place: lightly soiled dishes and an hour to spare. For everything else, set the eco cycle tonight and use the delayed start so it finishes as you get up.