Grade Level: 9th–12th Grade | Duration: 50 minutes

This hands-on STEAM lesson engages high school students in real-world mathematical modeling as they calculate their household energy consumption and design an energy-efficient solar-powered home. Students work through formulas to determine annual energy costs for common appliances, then apply their findings to make informed decisions about appliance selection within the constraints of a 25-panel solar system. The activity integrates science, mathematics, and financial literacy while promoting critical thinking about renewable energy and sustainable living. The lesson addresses multiple Alabama College and Career Ready standards, including investigating renewable and nonrenewable energy sources, using mathematical modeling to solve real-world financial problems, and constructing evidence-based explanations about resource management and human sustainability.

Learning Objectives

Students will use a formula to calculate their annual household energy use and investigate how the type of appliances and amount of use affects the cost of energy. Students will analyze which household appliances are best for energy efficiency and design a solar-powered home according to their argument and findings.

Background & Context

We rarely think about the costs incurred each time we flip a light switch, toast bread, or open the garage door. Yet every time we “plug in,” we’re not only spending money but also consuming natural resources. Those utilizing solar panels are accessing renewable energy—energy that comes from resources naturally replenished on a human timescale, including wind, solar, geothermal, biofuel, and hydro. We consider solar energy a sustainable resource, and as this technology becomes more cost-efficient and popular, it has the potential to play an important role in reducing carbon emissions, mitigating climate change, and leading us toward a more sustainable future.

Many new appliances feature an “Energy Star” label with an “Energy Guide” indicating the amount of energy used and estimated yearly operating cost. Other appliances list wattage—the energy consumed in one hour. How we use appliances and which appliances we purchase directly affect our electricity costs and consumption. To “think sustainably,” we can consider upgrades to our homes and businesses while using electricity more efficiently and sensibly.

Activity Structure

Materials Included

The lesson PDF contains comprehensive student handouts:

“Estimating Your Annual Household Energy Consumption and Cost” (4 pages)

• Name, date, and class fields
• Pre-filled table with 30+ common household appliances including wattage data
• Appliances range from low-energy items (LED bulbs at 8W, phone chargers at 5W) to high-energy items (water heater at 5,000W, electric dryer at 3,500W)
• Formula columns for converting watts to kilowatts, calculating daily usage, and determining daily/annual costs
• Spaces for students to add custom “Other” appliances
• Reflection questions about highest-energy appliances and potential improvements
• Summary boxes for total daily and annual energy use and costs

“Designing a Solar-Powered Home” (2 pages)

• Name and date fields
• Scenario framing: “You just won a FREE SOLAR-POWERED HOME!” with constraint of 25 solar panels at 250 watts each
• Calculation question: “How many watts of energy will you be able to use per day?”
• Appliance selection area with instructions to list choices and calculate total wattage without exceeding the limit
• Reflection question about additional energy-efficient design features
• Full-page blank space for sketching the solar-powered home design with solar panels and selected appliances

Materials Required

For each student:

• “Estimating Household Energy” handout (can be replaced with Excel spreadsheet—see Extension)
• “Designing a Solar-Powered Home” handout (can be replaced with poster/3-D model project—see Extension)
• Calculator
• Colored pencils for home design sketch

For the teacher:

• Local utility rate information (available from power company or from the U.S. Department of Energy resource linked in the lesson)

Extension Activities

Digital Literacy Integration: Students can use a computer and Excel spreadsheet to create the “Estimating Your Annual Energy Use” table using appropriate formulas. This approach builds spreadsheet skills and allows for easier manipulation of variables to test different scenarios.

Arts & Engineering Integration: Students can design a more detailed poster or build a 3-D model of their solar-powered home design. This extension transforms the activity into a multi-day project incorporating visual arts, architecture, and engineering design principles while reinforcing the energy efficiency concepts.

Teacher Resources

The lesson includes links to two key resources:

• U.S. Department of Energy – Estimating Appliance and Home Electronic Energy Use: Provides methodology for calculating energy consumption and current utility rate information
• SunPower Solar Resources: Offers information on solar panel sizing, output factors, and how many panels are needed for different household energy requirements