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Unit 1Lesson 5 3 min read

Energy Efficiency and Conservation

5/18

Learning Objectives

Distinguish between energy efficiency and energy conservation.
Explain why no energy transformation is 100% efficient due to the production of waste heat.
Identify practical ways to conserve energy in daily life.
Provide examples of energy-efficient technologies.

Using Energy Wisely

We rely on energy for almost everything we do, but the energy resources we use are not unlimited. It's important to use energy wisely. There are two main approaches to this: energy efficiency and energy conservation. While they sound similar, they mean different things.

Energy Conservation

Energy conservation means using less energy. It's about changing your habits and behaviors to reduce your overall energy consumption. Conservation is about the choice to use less.

Examples of Energy Conservation:

Turning off the lights when you leave a room.
Walking, biking, or taking public transit instead of driving a car.
Taking shorter showers to use less hot water.
Unplugging electronics when they are not in use (to avoid 'phantom load').
Putting on a sweater instead of turning up the thermostat in the winter.

Energy Efficiency

Energy efficiency means getting the same amount of work done while using less energy. It's not about changing your behavior, but about using better technology that doesn't waste as much energy.

Examples of Energy-Efficient Technologies:

Replacing an old incandescent light bulb with a new LED light bulb. Both produce the same amount of light, but the LED uses up to 80% less electricity.
Using a new, ENERGY STAR-rated refrigerator instead of an old one.
Driving a hybrid or electric car that gets more miles per gallon (or kilowatt-hour) than a standard gasoline car.

Why Nothing is 100% Efficient

Whenever energy is transformed from one form to another, some of that energy is always 'lost' as a less useful form, usually heat (thermal energy). This is a consequence of the Second Law of Thermodynamics.

Think about an old incandescent light bulb. Its purpose is to create light (radiant energy). However, it gets very hot to the touch. In fact, about 90% of the electrical energy it uses is converted into waste heat, and only 10% is converted into visible light! This makes it very inefficient.

An LED bulb is much more efficient because it converts a much larger percentage of its electrical energy into light and wastes very little as heat. However, even the LED is not 100% efficient; it still produces a small amount of waste heat. No device can ever be 100% efficient at converting energy into useful work.

By combining both energy conservation (good habits) and energy efficiency (good technology), we can significantly reduce our impact on the environment and save money on our energy bills.

Key Terms

**Energy Conservation
The practice of reducing energy consumption through behavioral changes.
**Energy Efficiency
The use of technology that requires less energy to perform the same function.
**Waste Heat
Thermal energy that is produced by a machine or other process as a byproduct and which is not useful for the intended purpose of the system.
**Incandescent Light Bulb
An electric light which produces light with a wire filament heated to a high temperature by an electric current. It is very inefficient.
**LED (Light-Emitting Diode)
A semiconductor light source that is highly energy-efficient.

Check Your Understanding

1

Replacing your old, single-pane windows with new, double-pane windows that reduce heat loss is an example of ________.

2

What form of energy is almost always produced as a 'waste' product during an energy transformation?

3

Turning off the television when you are finished watching it is an example of energy ________.