Watt Watchers of Texas: Texas is Too Good To Waste™

How Much Energy Do You Use?

Grade Level: , , ,

Lesson Overview: This lesson expands upon the awareness of a student’s energy usage learned in the Energy Home Survey lesson. The students will add math to their information to determine which appliances are energy eaters. They will work on utility math problems and a comparison of the results.

Time: 15 minute preparation, one day’s homework, one class

Materials: What is the Cost worksheet, calculators

 What is the Cost

Vocabulary: periodic appliance, incandescent and fluorescent lights

Background Information:

U.S. residents use more energy now than we ever have in the past. There are many reasons for this. As more people populate the country, energy needs rise. Technology advances, such as industrial processes, sophisticated machinery and computers also require increased energy. Our everyday lives are filled with electrical appliances that our grandparents never used.

This activity gives your students a chance to work on some real-life math problems. This activity bases its numbers on cost figures from one utility. Energy figures in your area may be different. Your local energy utility can give you figures that show the average expenditure per household in your community.

Setting the Stage:

Start by asking your students if they have ever heard their parents complain about the cost of energy. Explain that the monthly utility bill is directly related to the amount of energy the household uses, and that this activity will help them find the “energy-eaters” in the house. Show them a sample electricity bill from a local utility company.

Activity 1: What is the Cost?

Distribute the What is the Cost worksheet. Have students fill out the second and third columns (# on am, # on pm) on the front side at home, and the first column of the periodic appliance use chart. The next day, assist them in a few of the math problems and have them complete the charts and questions.

Part two includes appliances that are run periodically. Students fill out information relating to the number of loads they do each week. After reading the second chart, have the students estimate their energy bill. Compare with actual or sample bills.


After they have found out how much it costs to run appliances each day ask them if they found any they could live without (such as an electric can opener), or if there were any they could use less (shutting off lights and stereo when leaving the room). If students are having difficulty with calculations or want to expedite the process of calculating use and cost, consider referring them to an online calculator such as the Energy Use Calculator.

Light bulbs are the most omnipresent energy consumers in a home or school environment. Some light fixtures and ceilings fans have more than 1 bulb. Using what students know from the calculations on the worksheet, ask them to calculate how much they can save if they use only 1 bulb in those fixtures. Is that feasible? How much is the savings?


Bring in a speaker from your local utility to talk about ways to change habits to lower home energy costs, or have your school energy manager speak about energy saving techniques in the school.

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