Dishwashers
Dishwashers
History
American socialite Josephine Cochrane was frustrated at the way her servants were damaging her fine bone china by scrubbing it in the scullery sink. She is said to have remarked: “If nobody else is going to invent a dishwashing machine, I’ll do it myself.”
Working in a shed behind her home, she developed and patented a design employing water jets and a rack that would hold the soiled tableware in place inside a copper boiler. Powered by a motor, a wheel turned and squirted soapy water over the dishes to clean them. In 1886, Josephine patented her design, set up a manufacturing company, and began to supply the machines to restaurant businesses.
It was not until the social changes of the 1950s and the development of effective detergents, that ordinary households would acquire a dishwasher.
The UK dishwasher market
By 2018, 49% of British homes had dishwashers[1].
Innovation
Most of the energy use in dishwashers comes from heating up the water. So, the less water that there is to heat, and the lower the temperature difference between the water supply and the temperature at which it is used, the lower the overall energy consumption.
So the most energy efficient appliances and programmes tend to use water very efficiently as that keeps the energy use low. As a result, ‘Eco’ or energy-efficient programmes tend to take longer, sometimes up to two and a half hours. The lowest temperature programmes are usually 40-45C.
A few dishwashers allow ‘hot fill’ connections from the hot water system, which may mean that the water can be heated more cheaply by the central boiler or by another source such as solar panels. In practice, due to the small amount of water used in modern, efficient washes and the length of pipes from the hot water cylinder, these are only worthwhile for households that use hot washes. Research suggests that a well-organised dishwasher can use a small proportion of the energy and water used to wash by hand.
Labelling
Using new measurements which came into force on March 1 2021, dishwasher labels now display their energy efficiency on a visual scale from A to G. The new labelling also shows:
- Energy consumption in eco program per 100 cycles (kWh)
- Rated capacity in standard place settings for the eco program
- Duration of the eco program (hours and minutes)
- Water consumption per cycle in eco program (litres)
- Airborne acoustical noise emissions (dB(A) and noise emission class
There is also a QR code on the label for more product information. This links to the product on the manufacturer’s website. By hovering a smartphone camera over the the code, a link to the webpage is opened, where the consumer can get more details on the product.
[1] ONS, Family spending in the UK: April 2017 to March 2018, Table A45, Percentage of households with durable goods