Lesson: Household Energy Conservation and Efficiency

Contributed by: Office of Educational Partnerships, Clarkson University, Potsdam, NY

Two photos show a girl using a laptop computer on a sofa and two boys using hand-held controllers to play a game.
With new technology hitting the marketplace every day, home energy consumption continues to increase.
Copyright © (left) National Institutes of Health and (right) Health Information Technology, Agency for Healthcare Research and Quality, US Department of Health and Human Services http://www.noisyplanet.nidcd.nih.gov/parents/pages/athome.aspx http://healthit.ahrq.gov/images/apr10patientempowerment/Patient%20Empowerment%20508/images/image19.png


Students complete three different activities to evaluate the energy consumption in a household and explore potential ways to reduce that consumption. The focus is on conservation and energy efficient electrical devices and appliances.The lesson reinforces the relationship between power and energy and associated measurements and calculations required to evaluate energy consumption. The lesson provides students with more concrete information for completing their culminating unit assignment.

Engineering Connection

Evaluating energy consumption is the first step engineers must take when trying to reduce energy consumption. This step is part of the "understand the problem" and "gather information" steps in the problem solving spiral.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

  • Develop descriptions, explanations, predictions, and models using evidence. Students should base their explanation on what they observed, and as they develop cognitive skills, they should be able to differentiate explanation from description--providing causes for effects and establishing relationships based on evidence and logical argument. This standard requires a subject matter knowledge base so the students can effectively conduct investigations, because developing explanations establishes connections between the content of science and the contexts within which students develop new knowledge. (Grades 5 - 8) Details... View more aligned curriculum... Give feedback on this alignment...
  • Think critically and logically to make the relationships between evidence and explanations. Thinking critically about evidence includes deciding what evidence should be used and accounting for anomalous data. Specifically, students should be able to review data from a simple experiment, summarize the data, and form a logical argument about the cause-and-effect relationships in the experiment. Students should begin to state some explanations in terms of the relationship between two or more variables. (Grades 5 - 8) Details... View more aligned curriculum... Give feedback on this alignment...
  • Communicate scientific procedures and explanations. With practice, students should become competent at communicating experimental methods, following instructions, describing observations, summarizing the results of other groups, and telling other students about investigations and explanations. (Grades 5 - 8) Details... View more aligned curriculum... Give feedback on this alignment...
  • Use mathematics in all aspects of scientific inquiry. Mathematics is essential to asking and answering questions about the natural world. Mathematics can be used to ask questions; to gather, organize, and present data; and to structure convincing explanations. (Grades 5 - 8) Details... View more aligned curriculum... Give feedback on this alignment...
  • Mathematics is important in all aspects of scientific inquiry. (Grades 5 - 8) Details... View more aligned curriculum... Give feedback on this alignment...
  • Energy is a property of many substances and is associated with heat, light, electricity, mechanical motion, sound, nuclei, and the nature of a chemical. Energy is transferred in many ways. (Grades 5 - 8) Details... View more aligned curriculum... Give feedback on this alignment...
  • Electrical circuits provide a means of transferring electrical energy when heat, light, sound, and chemical changes are produced. (Grades 5 - 8) Details... View more aligned curriculum... Give feedback on this alignment...
  • Science influences society through its knowledge and world view. Scientific knowledge and the procedures used by scientists influence the way many individuals in society think about themselves, others, and the environment. The effect of science on society is neither entirely beneficial nor entirely detrimental. (Grades 5 - 8) Details... View more aligned curriculum... Give feedback on this alignment...
  • Technology influences society through its products and processes. Technology influences the quality of life and the ways people act and interact. Technological changes are often accompanied by social, political, and economic changes that can be beneficial or detrimental to individuals and to society. Social needs, attitudes, and values influence the direction of technological development. (Grades 5 - 8) Details... View more aligned curriculum... Give feedback on this alignment...
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Learning Objectives

After this lesson, students should be able to:

  • Calculate energy use and analyze how changing behaviors and appliances affects energy use.
  • Conduct an experiment and make comparisons based on experimental evidence.


How are your unit projects going? Have you come up with some good ideas about how you might reduce your energy consumption? In this lesson, we will explore more closely how we use energy in our homes and identify some ideas for conserving energy or using it more efficiently. Recall these terms:

  • Conservation – not using consumer energy products (for example, turning lights off, walking instead of driving)
  • Efficiency – benefiting from the value of using energy (for example, still being mobile), but consuming much less energy to meet same goal (for example, using an automobile with high miles per gallon)

Pie chart shows the relative amount of electricity consumed in a US household. Kitchen appliances consume the greatest percentage.
Household electricity use in the U.S.
Copyright © (data) US Department of Energy's Energy Information Agency

We use energy in our lives everyday. Our homes use energy in many ways. Home heating/cooling systems are the largest consumer of energy in most U.S. households. Heating water is also a large energy consumer.

Another large energy consumer category is electric lighting and appliances. (Refer to data in the Excel graphing activity, lesson 1, for specific information.) Our homes are filled with appliances that use electrical energy to work for us. Toasters, microwave ovens, televisions and computers are examples of the appliances we use everyday. We compare electrical energy use in units called watt-hours or kilowatt-hours. Lighting accounts for 20-25% of all the electricity used in the U.S. On average, a household uses 5-10% of its energy for lighting. A commercial industry on the other hand consumes 20-30% of its energy in lighting alone; 50% or more of the energy used is wasted by obsolete equipment, inadequate maintenance, or inefficient use.

Consumer demand for appliances that turn on quickly and LED lights that stay on all the time creates a constant "stand by" power requirement that can be very substantial. This power is sometimes called "leaking electricity." Unplugging these appliances is the only way to reduce the stand by power load. (Show some examples on computer, TV, other appliances that might be in the classroom.)

Energy savings for lighting will require either reduction in use or more efficient usage. New technologies have provided significant reductions in the power needed for lighting.

Lesson Background and Concepts for Teachers

The use of electricity in the home was addressed in the graphing activity of lesson 1. Many of the concepts covered here were introduced (superficially) in that lesson. The general concepts of this lesson include:

  1. Energy conservation can be defined as the protection, preservation, management, or restoration of our energy resources.
  2. Conservation is one of the ways we can reduce energy use, thus reducing the amount of pollutants put into our atmosphere from the burning of fossil fuels and reducing the negative effects resulting from the combustion of these fuels.
  3. Conservation methods include modifications to our daily behaviors to reduce energy consumption (for example, turning off lights).
  4. Efficiency can be achieved by choosing energy-efficient products. These products still provide work, light or heat, but do so with less energy consumption than less-efficient products.

Light Bulb Options

75W incandescent equivalent bulbs

Compact fluorescent light bulbs (CFLs)

See photo and product description at EarthEasy's website: http://eartheasy.com/live_energyeff_lighting.htm

  • Wattage: 18 W (76% energy savings)
  • Lasts: 8,000 hours
  • Cost: $22 per pack
  • Requires special bulb recycling to collect and contain mercury

Cold cathode fluorescents (CCFLs)

18 watts = 75 watt incandescent equivalent

See photo and product description at BetterBulb at: http://ww31.betterbulb.com/

  • Wattage: 18 W (76% energy savings)
  • Lasts: 25,000 hours
  • Low energy costs; less mercury then CFLs

Light Emitting Diode (LED)

The 5 Watt LED light:

  • is efficient and cost effective
  • is the most powerful direct replacement bulb
  • fits standard sockets

See photo and product description at EarthTechProducts at: http://www.earthtechproducts.com/energy-saving-led-light-bulbs.html

  • Wattage: 5 W (93% energy savings)
  • Cost: $60
  • No mercury; expensive


compact fluorescent lamp : (CFL) A modern light bulb that converts electricity into light through the excitation of

energy audit: A study of energy use and losses in a home, business or other system.

incandescent bulb: Traditional light bulb that converts electricity to light by heating a thin wire until it glows.

LED: A light emitting diode is a solid-state semiconductor device that converts electrical energy directly into light. The process of an electron moving in the semi-conductor releases energy and produces photons with visible wavelengths.

life cycle cost analysis: Analysis of the total capital and operating cost of a product.

Associated Activities

  • Watt Meters to Measure Energy Consumption - (Day 1) Students use watt meters to measure the power required and calculate energy used from various electrical devices and household appliances.
  • Household Energy Audit - (Assign Day 1, Day2) Students review the electrical appliances used at home and estimate the energy used for each. The results can help to show the energy hogs that could benefit from conservation or improved efficiency. Combination in-class and homework activity.
  • Light vs. Heat Bulbs - (Day 3) Students measure the light output and temperature (as a measure of heat output) for three types of light bulbs to identify why some light bulbs are more efficient (more light with less energy) than others.



Worksheet & Homework: Assign students the Light Bulbs Activity Worksheet and Homework. The homework may be redundant if a thorough home energy audit is also done.

Homework & Activity Sheets: Assign students the home energy audit homework/activity sheets.


Energy Star. Compact Fluorescent Light Bulbs, U.S. EPA and U.S. Department of Energy. Accessed December 30, 2008. http://www.energystar.gov/index.cfm?c=cfls.pr_cfls

Other Related Information

This lesson was originally published by the Clarkson University K-12 Project Based Learning Partnership Program and may be accessed at http://www.clarkson.edu/highschool/k12/project/energysystems.html.


Jan DeWaters; Susan Powers; and a number of Clarkson and St. Lawrence University students in the K-12 Project Based Learning Partnership Program


© 2013 by Regents of the University of Colorado; original © 2008 Clarkson University

Supporting Program

Office of Educational Partnerships, Clarkson University, Potsdam, NY


This lesson was developed under National Science Foundation grant nos. DUE 0428127 and DGE 0338216. However, these contents do not necessarily represent the policies of the National Science Foundation, and you should not assume endorsement by the federal government.