Improving efficiency

Efficient devices use less fuel than less efficient devices.

They can operate at a lower power because less of the supplied energy store is wasted.

Efficiency can be improved by:

  • making devices and machines from materials which reduce unwanted energy transfer;
  • improving the technology used, for example modern LEDs are much more efficient than traditional filament bulbs;
  • using insulation to prevent heat energy losses to the surroundings.

Electrical appliances

Many electrical appliances used in the home transfer electrical energy to other useful forms.

ApplianceUseful energyWasted energy
Electric kettleEnergy that heats the water.Heat energy store heating the kettle. Infrared radiation transferred to the surroundings.
HairdryerHeat energy store heating the air. Kinetic energy of the fan that blows the air. Sound radiation. Heat energy store heating the hairdryer. Infrared radiation transferred to the surroundings.
Light bulbLight radiation given out by the hot filament.Infrared radiation transferred to the surroundings.
TVLight radiation that creates images for the user. Sound radiation that creates audio for the user. Heat energy store heating the TV set. Infrared radiation transferred to the surroundings.