The dishwasher, this appliance that we sometimes feel guilty about using, as if washing dishes by hand remained, in principle, the most virtuous gesture. Except the numbers tell a completely different story.
As part of its series of “Eco-Friendly Matches” videos, produced in partnership with ADEME, the Ecological Transition Agency, the question was asked head-on: which is really more ecological between washing your dishes by hand or in the dishwasher? The answer, with supporting figures, leans clearly in favor of the machine. Modern appliances consume between 10 and 15 liters of water per complete cycle, an amount much less than that required to wash by hand without careful attention to the flow rate of the tap. A Eurofins study carried out for GIFAM (Interprofessional Group of Household Appliance Manufacturers), carried out with 2,000 people, goes even further: washing the dishes of 12 guests by hand would consume between 42 and 105 liters of lukewarm water, depending on each person's habits.
This result is often surprising, as the image of the dishwasher remains associated with consumption rather than economy. The explanation lies in a very human bias, widely documented by experts in the sector: we see the water flowing from the tap, we hear the sound of the continuous jet, while the water circulating in the machine remains invisible, hidden in the tank. This direct perception instinctively gives the impression that manual washing is more sparing, while the measured reality says precisely the opposite. The gap widens even further when the tap remains open continuously throughout the wash, a very widespread habit.

What this task actually involves

Filling and starting the dishwasher involves placing the dirty dishes in the appliance baskets, adding the tablet or detergent, selecting the appropriate program, then starting the cycle. Allow around 5 minutes for this operation, a quick gesture that occurs several times a week depending on the consumption rate of the household.

Tips and tricks for truly economical washing

Absolutely avoid pre-rinsing dishes under the tap before placing them in the dishwasher: this reflex, still very widespread, consumes between 15 and 20 liters of additional water per cycle according to several specialized analyses, i.e. more than what the machine itself uses to wash everything. A simple scrape of the remains into the trash can is more than enough, as modern devices are designed to effectively deal with common dirt.
Waiting until the dishwasher is completely full before starting a cycle considerably optimizes the ratio between water and energy consumed on the one hand, and the quantity of dishes actually washed on the other. Starting a machine half empty means wasting a good part of the savings potential that the device can offer.
Favoring the eco program, rather than the intensive cycle, significantly reduces energy consumption without significantly compromising the result for common dishes: this program certainly washes at a lower temperature, but over a longer duration, which largely compensates in terms of cleaning efficiency.

Contrary to popular belief, the dishwasher remains, according to ADEME itself, the most water-saving solution in the vast majority of cases. Something as simple as waiting until the machine is full before starting it can make a real difference, much more than the reassuring feeling of "making an effort" by washing by hand.