Dishwashers vs. hand washing

Dishwashers, invented by a wealthy woman, in 1893 to stop her maids chipping her china, are one of the most popular time and effort saving devices in modern homes. But are dishwashers better for the environment than hand washing? Different dishwashers have different environmental 'footprints' and if you are about to purchase a new one this should be a consideration. But how does using your dishwasher stack up against washing dishes by hand? Both use water, electricity and cleaning chemicals.

Dishwashers and the environment

The impact of dishwashers on the environment could be considered in two parts. Firstly, the manufacture of the machine itself requires the use of energy, which currently comes from fossil fuels, creating pollution and emitting carbon dioxide, a 'greenhouse gas'. It also requires the use of plastics, which again creates toxic pollution, and metals, which must be mined. The materials and parts usually also make several journeys around the globe to be processed and assembled. So every new appliance has an impact on the environment, simply by being made.

The second factor is in the machine's operation, and it is here that dishwashers can be better for the environment than hand washing.

Are dishwashers more environmentally friendly than hand washing?

The answer is that it depends on your dishwasher and on your hand washing technique. Consider the following factors.

• Water usage. A good dishwasher can use less water than careless hand dish washing. If you rinse in running water, for example, you are likely to use more water than an efficient dishwater cycle. However, an older mechanical dishwasher will use more water than a careful person

• Water heating can be more efficient in a dishwasher because there is no heat loss in transferring water to the sink, or in the water sitting in the sink for some time. This also depends on your hot water system; an electric heater just above the pipe is very efficient

• Of course, a dishwasher uses energy to run it

• Most dishwashing detergents contain phosphates, bleaching agents, surfactants, enzymes and anti corrosion agents. They may also contain anti foaming, anti caking and anti corrosion agents, sand (which is not good for your dishes!), gelling agents and starches. Many of these things have harmful environmental impacts. If you use a dishwasher, try to use as environmentally friendly a detergent as you can.

• If buying a new dishwasher, choose the machine based on it having as low an environmental impact as possible

The manufacture of any new appliance has an impact on the environment. Depending on how they are used and on the brand, though, dishwashers can be better for the environment than hand washing. If you are a careless hand washer then a dishwasher may actually reduce your use of water and energy.