A dishwasher display showing several hours can make the eco programme look wasteful. Running time, however, is not the same measurement as energy use. Heating intensity and the programme’s sequence matter too.
Bosch’s explanation of its eco mode describes using a longer cycle with less intensive water heating than shorter programmes. The manufacturer also says that programme choice should match the load and degree of soiling. Exact consumption depends on the model and conditions.
Compare energy with energy
Open the manual for your own dishwasher and find the programme table. Compare the stated kilowatt-hours and water use, noting the test conditions and any options that change them. Do not rank programmes solely by the countdown shown on the display.
As a fictional arithmetic example, a cycle using 0.8 kWh consumes less electrical energy than one using 1.2 kWh, even if the first takes longer. The duration alone cannot reverse that comparison. These numbers illustrate the units and are not measurements of a particular appliance.
Extra drying, intensive zones or other selected options may alter the result. Record the full programme configuration if you are comparing your own usage.
Give the programme a suitable load
Load the machine as instructed so water can reach the items and the spray arms can move. Scrape away food remnants according to the manual, and use the recommended detergent. Do not overload the racks to make a single cycle appear more efficient.
Some items and cleaning needs require a different programme or should not go in the dishwasher at all. Follow the appliance and item instructions rather than treating eco as the answer to every load.
Keep filters and the machine maintained on the manufacturer’s schedule. If cleaning results deteriorate, investigate the cause instead of repeatedly running the same load. A useful resource-saving routine combines an appropriate cycle with correct loading and a machine that can do its job properly.