Comparing energy use of old and new, highly energy-efficient appliances
To replace or not to replace
Knowing exactly when to replace an appliance, especially one that is still working, can be difficult.
Generally, older washing machines will consume more energy than a new, highly energy-efficient one, as EU regulations setting limits to energy use have come into effect. On average, washing machines sold in 1990 used 31% more energy than those available today. 
Actual energy consumption can vary considerably from model to model however, Which? calculated the annual energy costs of 216 washing machines and found they vary between £12 and £47 per year (based on washing four loads a week at 40°C). 
Monitoring the energy usage of your current appliance
You may find it useful to monitor the actual energy consumption of your washing machine. This can be done using a plug-in energy-usage meter. This is plugged into the socket and the appliance is plugged into the meter. Monitoring electricity usage for a month, or even a week, allows you to gain an idea of the annual consumption.
Bear in mind, you may use your washing machine more frequently at certain times of the year, such as the school holidays. So ensure you perform the test during a time that represents your typical usage.
The EU Energy Label shows the average annual electricity use of appliances.So you can easily find out how your washing machine fares compares to a new model before committing to a purchase.
What size washing machine?
If you are planning to buy a new washing machine, picking a drum size that best suits your needs will ensure no energy and water is wasted. Drum sizes available range from 5.5kg to 11kg.
The average household does more thanfive washes a week. A single-person household will have smaller individual loads than a family, so a smaller drum would be appropriate. A family or multi-person household may be able to reduce the number of washes needed by using a machine with a large drum and save water, energy and money in the process.
In any case, look out for the Energy Label – the best performing models on the market will be rated A+++ and you can see the average annual energy and water consumption on the label.