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 LEDLight-Emitting Diode. LEDs glow when current passes through them. are much more efficient than traditional filamentA thin, high resistance wire that gets hot and glows when a current flows through it causing it to emit heat and light. Filaments are used in some types of bulb and electrical heaters. bulbs;
- using insulationThings which protect by preventing a loss of heat. to prevent heat energy losses to the surroundings.
Electrical appliances
Many electrical appliances used in the home transfer electrical energy to other non-useful forms.
| Appliance | Useful energy | Wasted energy |
| Electric kettle | Energy that heats the water. | Heat energy store heating the kettle. Heat energy lost to the surroundings. |
| Hairdryer | Heat 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 bulb | Light radiation given out by the hot filament. | Infrared radiation transferred to the surroundings. |
| TV | Light 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. |
| Appliance | Electric kettle |
|---|---|
| Useful energy | Energy that heats the water. |
| Wasted energy | Heat energy store heating the kettle. Heat energy lost to the surroundings. |
| Appliance | Hairdryer |
|---|---|
| Useful energy | Heat energy store heating the air. Kinetic energy of the fan that blows the air. |
| Wasted energy | Sound radiation. Heat energy store heating the hairdryer. Infrared radiation transferred to the surroundings. |
| Appliance | Light bulb |
|---|---|
| Useful energy | Light radiation given out by the hot filament. |
| Wasted energy | Infrared radiation transferred to the surroundings. |
| Appliance | TV |
|---|---|
| Useful energy | Light radiation that creates images for the user. Sound radiation that creates audio for the user. |
| Wasted energy | Heat energy store heating the TV set. Infrared radiation transferred to the surroundings. |