Student worksheet + teacher guide
A two-page PDF with a five-appliance table, discussion prompts, formulas, and teacher notes.
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Home Appliance Energy Audit
Help students turn appliance watts and daily use into annual kWh and cost. This ready-to-run activity includes a printable worksheet, teacher guide, editable calculator, and open dataset—without accounts, ads, or email collection.
- 30–45 minutes
- Middle school through adult learning
- CC BY 4.0
Everything in one place
Choose the resources your class needs
Each file works independently, or use all four for the complete activity.
Interactive cost calculator
Students replace assumptions with measured watts, hours per day, and a local electricity rate.
Open calculatorOpen appliance dataset
Download 38 household examples with typical watts, assumed use, annual kWh, and estimated cost.
Download CSVFree calculator embed
Keep students on your lesson page with a copy-and-paste iframe and visible HowMuchWatts attribution.
Get embed code Teacher-ready sequence
30-minute lesson plan
- 5 min Introduce power and energy.
Watts describe the rate of using energy; kilowatt-hours describe the amount used over time. Compare the fixed kWh-to-Wh conversion with the time-based kWh-to-watts calculation.
- 10 min Collect five examples.
Use appliance labels, a plug-in meter, or rows from the open dataset. Estimate realistic daily hours.
- 10 min Calculate and check.
Students calculate annual kWh and cost by hand, then compare their result with the interactive calculator.
- 5 min Discuss assumptions.
Identify the largest cost, the weakest assumption, and one realistic change that could reduce energy use.
Worked example
From a 60 W fan to annual cost
A 60 W fan used for 8 hours per day consumes 175.2 kWh per year. At an example rate of USD $0.17/kWh, the estimated annual cost is USD $29.78.
This is an estimate. Real use changes with speed settings, cycling, standby power, schedule, and the all-in electricity rate.
annual kWh = watts ÷ 1,000 × hours/day × 365 annual cost = annual kWh × electricity rate Open and adaptable
Use it in your own course
The worksheet and dataset are licensed under CC BY 4.0. You may copy, translate, adapt, and republish them with attribution to HowMuchWatts and a link to this page.
The activity is keyboard accessible, the PDF has selectable text, and the calculator works in a browser without registration. Review the calculation methodology or the full source and assumption notes before adapting the data.