If a device has energy efficiency of 25%, what fraction of input energy is wasted, and how could efficiency be improved?

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Multiple Choice

If a device has energy efficiency of 25%, what fraction of input energy is wasted, and how could efficiency be improved?

Efficiency is about how much of the energy that goes into a device actually does useful work. If only 25% comes out as useful energy, the rest is wasted. So the wasted portion is 100% − 25% = 75% of the input energy, i.e., three-quarters. To improve efficiency, aim to increase the useful energy portion and cut losses. This can mean using a more efficient device or better components, reducing energy lost as heat, friction, or electrical resistance, keeping the device well maintained, and, where possible, recovering or reusing some of the wasted energy. For example, upgrading to a higher-efficiency motor or LED lighting, or adding insulation and proper lubrication to reduce heat and friction losses.

Efficiency is about how much of the energy that goes into a device actually does useful work. If only 25% comes out as useful energy, the rest is wasted. So the wasted portion is 100% − 25% = 75% of the input energy, i.e., three-quarters.

To improve efficiency, aim to increase the useful energy portion and cut losses. This can mean using a more efficient device or better components, reducing energy lost as heat, friction, or electrical resistance, keeping the device well maintained, and, where possible, recovering or reusing some of the wasted energy. For example, upgrading to a higher-efficiency motor or LED lighting, or adding insulation and proper lubrication to reduce heat and friction losses.

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