UNIT 4 – PHYSICAL WORLD Energy efficiency


The many electrical items in use in our homes means that the cost quickly adds up. Energy efficiency is the percentage of electrical energy that is converted to a useful form.


A household can take the following steps to use less electrical energy and become more energy efficient: • Turn off lights, appliances and devices when not in use. • Turn off appliances at the plug instead of leaving them on standby. • Fit a smart meter to monitor how much electricity is being used. • Use high wattage appliances such as dishwashers and tumble dryers less frequently. • Use CFL or LED bulbs rather than filament bulbs. • Buy energy-efficient appliances.


: Fig. 32.5 Energy labelling


Some electrical appliances sold in the EU, including fridges, dishwashers, washing machines, televisions and lamps, must display energy labels to show how efficient they are.


The energy rating scale goes from A to G, according to energy efficiency.


• Class A (green label) appliances use the least energy, making them the most efficient.


• Class G (red label) appliances use the most energy, making them the least efficient.


? TEST TUBE


3. List five simple steps you can take to reduce the amount of energy you use at home. 4. Research the following: • Which appliance uses the least electrical energy for cooking? • Does the volume of water boiled in a kettle affect its energy use?


• Does the amount of clothes being washed and the temperature used in a washing machine affect its energy use?


5. Identify two appliances in your home that display their energy labels and note their energy efficiency rating.


318 Elements of Science : Fig. 32.6 An EU energy label


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